Our partner in podcasting, The Gravel Ride Podcast, sits down this week with bicycle industry pioneer, Craig Calfee. Craig has been an industry leader for decades with his work on the Calfee brand and many other collaborations throughout the industry. You cannot find someone more knowledgeable about carbon (or bamboo) as a frame material.
Calfee Design Website – Calfee Design Factory Tour – Calfee Tetra Adventure Bike Review
Automatic Transcription by The Gravel Ride (please excuse all errors)
[00:00:04] Randall: Welcome to the gravel ride podcast. I’m your host Randall Jacobs and our guest today is Craig Calfee. Craig is the founder of Calfee Design, the innovator behind the first full carbon frames to race in the tour de France, the originator of numerous technologies adopted throughout the cycling industry, and on a personal note has been a generous and consistent supporter of my own entrepreneurial journey. I am grateful to have him as a friend, and I’ve been looking forward to this conversation for some time. So with that, Craig, Calfee welcome to the podcast.
[00:00:32] Craig Calfee: Oh, thank you. Nice to be here.
[00:00:34] Randall: So, let’s start with, what’s your background, give your own story in your own words.
[00:00:40] Craig Calfee: Well, I’ve always written bikes. I mean, as a kid, that’s how I got around. And that’s, as you become an older child, you, uh, find your independence with moving about the world. And a bicycle of course, is the most efficient way to do that. And later on, I was a bike messenger in New York when I went to college and that kind of got me into bike design as much for the, uh, desire to make a bike that can withstand a lot of abuse. And later on, I used a bike for commuting to work at a job, building carbon fiber racing boats. And during that time I crashed my bike and needed a new frame. So I thought I’d make a frame at a carbon fiber, uh, tubing that I had been making at my.
[00:01:29] Randall: my job
[00:01:30] Craig Calfee: So this is back in 1987, by the way. So there wasn’t a, there were no YouTube videos on how to make your own carbon bike. So I pretty much had to invent a way to build the bike out of this tubing. And at the time there were aluminum lugged bikes, and I just, I knew already aluminum and carbon fiber don’t get along very well. So you have to really do a lot of things to, to accommodate that. And the existing bikes at the time were, uh, I would say experimental in the fact that they were just trying to glue aluminum to carbon and it really wasn’t working.
[00:02:05] So I came up with my own way and built my first bike and it turned out really well. And a lot of friends and, and bike racers who checked out the bikes that I I really should keep going with it. So I felt like I discovered carbon fiber as a, as the perfect bicycle material before anyone else. Uh, and actually, uh, right at that time, Kestrel came out with their first bike, uh, the K 1000 or something. Um, anyway that was uh, that was in 87, 88. And, uh, I felt like I should really, you know give it a go. So I moved out to California and started a bike company.
[00:02:48] Randall: So just to be clear, you were actually making the tubes, you weren’t buying tubes. So you’re making the tubes out of the raw carbon or some pre-printed carbon. then you came up with your own way of, uh, joining those tubes.
[00:03:01] Craig Calfee: Yeah. I worked on a braiding machine, so it was actually a a hundred year old, uh, shoelace braider, uh, from back in Massachusetts. There’s a lot of old textile machinery braiding is, uh, you know, your braided socks and, you know, nylon rope is braided. So this is a 72 carrier braider, which means 72 spools of carbon fiber.
[00:03:25] Are winding in and out braiding this tube and you just run it back and forth through this braider a few times. And now you have a thick enough wall to, uh, I developed a and tape wrapping method at that job and came up with a pretty decent way to make a bicycle tube. So that was kind of the beginning of that.
[00:03:47] Uh, and since then I’ve explored all kinds of methods for making tubing, mainly through subcontractors who specialize in things like filament winding and roll wrapping. And, uh, pultrusion, you know, all kinds of ways to make tubing. And that does relate to kind of an inspiration for me, where I realized that, uh, carbon fiber, you know, high performance composites are relatively young and new in the world of technology where metals are, you know, the metals have been around since the bronze age.
[00:04:21] I mean, literally 5,000 years of development happened with metals, carbon fiber, uh, high-performance composites have only really been around since world war two. So that’s a huge gap in development that hasn’t happened with composites. So that to me felt like, oh, there’s some job security for a guy who likes to invent things. So that was my, a kind of full force to get me to really focus on composite materials.
[00:04:51] Randall: Were you that insightful in terms of the historical context at the time, or is that kind of a retro or retrospective reflection?
[00:04:58] Craig Calfee: I think, I don’t know. I think I may have read about that. Um, I a friend who had a library card at MIT and I pretty much lived there for a few weeks every, uh, master’s thesis and PhD thesis on bicycles that they had in their library. And I think somewhere in there was a, uh, a topic on composites and comparing the technology of composites.
[00:05:23] So. I probably that from some reading I did, or maybe I did invent that out of thin air. I don’t remember, uh, nonetheless, uh, the fact of it is, you know, not, not a whole lot of mental energy has been put into coming up with ways of processing fiber and resin compared to metal. So to me that just opens up a wide world of, of innovation.
[00:05:49] Randall: Um, and so the first frame was that, um, you’re creating essentially uniform tubes and then mitering them, joining them, wrapping them as you do with your current bamboo frames or what was happening there.
[00:06:02] Craig Calfee: Uh, it’s more like the, uh, our, our carbon fiber frames were laminating carbon fabric in metal dyes, and those are not mitered tubes fitting into the dyes. And that’s, that’s a process. I got my first patent on. And it, uh, so in the process of compressing the carbon fabric against the tubes, you’re you end up with these gussets in what is traditionally the parting line of a mold and rather than trim them off completely.
[00:06:31] I, I use them as reinforcing ribs.
[00:06:35] Randall: Yep. Okay. So that explains the, the, that distinctive element that continues with your, um, some of your, uh, to tube, uh, currently
[00:06:48] Craig Calfee: them
[00:06:49] the hand wrapping technique from that you currently see on the bamboo bikes came from developing a tandem frame, or basically a frame whose production numbers don’t justify the tooling costs. Um, so that’s hand wrapped. That’s just literally lashed to. Yeah. And a point of note, there is I was a boy scout growing up and, uh, there’s this merit badge called pioneering merit badge.
[00:07:16] And I really enjoyed pioneering merit badge because it involved lashing row, uh, poles together with rope and the pro you had to do with this one project. And I did a tower and it was this enormous structure that went just straight up like a flagpole, but it was it involved a bunch of tetrahedrons, uh, stacked on top of each other and lashed together.
[00:07:41] you know, culminating in a pole that went up. I don’t remember how tall it was, but it was, it was really impressive. And everybody, you know, thought, wow, this is incredible of poles and some rope. And here we have this massive tower. So anyway, I was into things together since a young age.
[00:08:00] And so I immediately came up with the, uh, the last tube concept. Which is where the, now the bamboo bikes are. course there’s a specific pattern to the wrapping, but, um, the concept is basically using fiber to lash stuff together,
[00:08:16] Randall: When it immediately brings to mind, what’s possible with current generation of additive production techniques. Uh, whereas before you could make small components and then lash them together to create structures that otherwise aren’t manufacturable.
[00:08:31] Now you’d be able to say, print it out though. Those, you know, those printed out materials don’t have the performance characteristics of a, you know, a uni directional carbon of the sword that you’re working with currently.
[00:08:42] Craig Calfee: right?
[00:08:43] Randall: Um, so we’ve gone deep nerd here. We’re going to, I’m going to pull us out and say, okay, uh, lots of time for this.
[00:08:49] This is going to be a double episode. Uh, so next up, let’s talk about those frames, uh, saw their big debut.
[00:08:59] Craig Calfee: Yeah. So, um, we started making custom geometry for a. In 1989 and selling them and so big and tall, and that the idea of custom geometry frames was, uh, you know, pretty esoteric. And the pro racers were, we’re using a lot of custom frames. So Greg Lamond, uh, was in search of a carbon fiber, uh, custom frame builder in, uh, 1990.
[00:09:31] And, uh, no one really was doing it. We were literally the only company making custom carbon frame bikes. So he, uh, found out about us, uh, effectively discovered us, shall we say? And, uh, it didn’t take long for him to order up 18 of them for his, his, uh, team Z, uh, teammates. He was sponsoring his own team with a Lamont brand.
[00:09:56] So we didn’t have to sponsor him. He basically paid for the frame. Put his name on them. And, and, uh, now we’re now we’re on the defending champions, a tour de France team. So that was a huge break obviously. And it was really a pleasure working with Greg and getting to know the demands of the pro Peloton, uh, you know, that really launched us.
[00:10:21] So that was, uh, quite a splash. And, you know, it always is a great answer to the question. Oh, so who rides your bike kind of thing. you know, you have the, the full-on best one in the world at the time. So, so that was a fun thing.
[00:10:39] Randall: And the name of the company at the time was,
[00:10:41] Craig Calfee: Uh, carbon frames.
[00:10:42] Randall: yeah. So anyone wanting
[00:10:45] dig up the historical record,
[00:10:47] Craig Calfee: is this too generic? You know, the other to what you’re talking about, the adventure bikes. Yeah, we had to stop. I mean, carbon frames is a terrible name because everyone started talking about all carbon fiber frames as carbon frames. So we thought that was cool, you know, like Kleenex, you know, uh, and then we came up with the adventure bike, you know, with very early, uh, adventure bike.
[00:11:11] And it was just, we called it the adventure bike. And now there’s a classification called adventure bikes that, you know, so, um, I think we, we, we went too generic on how we named our models.
[00:11:26] Randall: I’ve drawn from the rich tradition, a tradition of Greek, you know, uh, philosophy for naming my own companies in the like,
[00:11:35] Craig Calfee: Yeah.
[00:11:36] Randall: uh, um, and then next up, uh, so you’ve worked with Greg Lamond on those frames. Carbon frames is up and running and you’re, you’re producing custom geo frames and you’re starting to get at some scale at this point and some notoriety.
[00:11:52] next up you were working on your bamboo bikes. When we talk about that
[00:11:57] Craig Calfee: Yeah, that was say, I’m kind of at the, at the time, it was just a way to get publicity. So at the Interbike trade show, you’d have a few creative people making some wacky bikes out of beer cans or, or other just weird things just to get attention, just, just to send the media over to your booth, to take a picture of some wacky thing that you’re doing.
[00:12:20] yeah, we got to do something like that to get, get some attention. And the, uh, so I was looking around for some PVC pipe. Maybe I was going to do a PVC pipe bike, and I wasn’t really sure, but I knew that we could just wrap any tube. Make a bike out of literally anything. So, um, my dog was playing with some bamboo behind the shop.
[00:12:42] Uh, she was a stick dog, so she loved to clamp onto a stick and you could swing her around by the, by the sticks. She’s a pit bull and lab mix. Anyway, we ran out of sticks. Uh, cause we only had one little tree in the back, but we did have some bamboos. So she came up with a piece of bamboo and I was her around by it, expecting it to break off in her mouth because I just wasn’t aware of how strong bamboo was, but it turned out it was really quite strong.
[00:13:12] And I said, oh, let’s make a bike out of this stuff. And sure enough, uh, the bike was, uh, quite a attention getter. It got the quarter page and bicycling magazine so that, you know mission accomplished on that front. And, but the bike itself rode really well.
[00:13:29] Randall: well
[00:13:30] Craig Calfee: Um, when I wrote my first carbon bike, uh, the very first ride on my very first carbon bike, I was struck by how smooth it was.
[00:13:38] It had this vibration damping that was, you know, just super noticeable and, and that really kind of lit a fire under my butt thinking, wow, this is really cool. When I built my first bamboo bike, I had that same feeling again, how smooth It was It was amazing for its vibration damping. So, uh, I knew I was onto something at that point.
[00:14:02] Uh, that first bike was a little too flexy, but, uh, the second bike I built was significantly stiffer and was an actual, real rideable bike. So, uh, from that point, uh, we just started building a few here and there and it was still a novelty item until about, uh, 1999, 2000. When a few people who had been riding them, or like, I want another one, I I want to know mountain bike this time.
[00:14:29] So as it was just starting to get known and, uh, we started selling them through dealers. And I mean there’s a lot of stories I can tell on how that evolved and how people started actually believing that a bamboo bike could actually exist in the world. So it took a while though.
[00:14:49] Randall: I think there’s a whole thread that we could tug on maybe in a subsequent episode where we focus just on the bamboo bike revolution.
[00:14:57] Craig Calfee: Yeah. Yeah. That’s um, there’s a lot of, lot of stuff going on there. I’m actually writing my second book on history of the bamboo bike, because there’s so many interesting angles to it, particularly in the.
[00:15:10] Randall: in Africa
[00:15:12] I’m struck by the juxtaposition of this bleeding edge. Uh, you know, high-tech material that you pioneered and then this going back to one of the most basic building materials, uh, that we have building bikes out of that. And in fact, um, on the one hand, there’s this, this extreme, know, difference in terms of the technology ization of each material.
[00:15:34] But on the other hand, there’s a parallel the sense that like carbon, in tubes is best, uh, you know, generally, uh, when it’s you need to write. Yeah, with maybe some cross fibers in order to prevent, prevent it from separating. And bamboo also has that characteristic of having, you know, you need directional fibers that are bonded together by some, uh, you know, some other material in, in the, in the bamboo
[00:15:58] Craig Calfee: Yeah. Yeah, it’s very, there’s a lot of similarities. I mean, bamboo is amazing just because it grows out of the ground and tubular for. And it grows a new, huge variety of diameters and wealth thicknesses. So if you’re looking for tubing, I mean, you don’t have to go much further. It’s amazing that it literally grows out of the ground that way.
[00:16:20] Randall: paint
[00:16:21] a picture for folks to, um, most of our listeners I’m guessing are in north America or, you know, other, uh, English-speaking parts of the world. I lived in China and as you’ve been, you see huge scaffolding, multi-story, you know, big buildings and the scaffolding isn’t made out of metal.
[00:16:37] It’s made out of bamboo lashed together with zip ties and pieces of wire. So it really speaks to the, the structural, uh, strength of the material and reliability of the material. and you know, should instill confidence when descending down a mountain.
[00:16:54] Craig Calfee: Oh yeah. No, it’s, I, I remember seeing bamboo and scaffolding many, many years. And I thought, well, of course, and the other reason they use it in scaffolding is when a typhoon hits and it, it kind of messes up the scaffolding of a construction site. Um, it’s, they’re back to work on the bamboo construction sites, much faster than the metal scaffolding sites, they have to deal with bent and distorted metal scaffolding, um, to replace those and fix that takes a lot longer where bamboo, they just bend it back and lash it back together.
[00:17:32] It’s it’s so much easier.
[00:17:35] Randall: there’s one more thing on this theme that I want to, uh, pull out before we move on, which is talk to me about the, the sustainability components of it. Um, starting with how it was done initially.
[00:17:47] And then now with say like, uh, biodegradable resins or, or other materials I can, this frame can be current.
[00:17:55] Craig Calfee: Uh, the short answer is yes, the frame can be composted. And the other cool thing is if you take care of it, it it’ll never compost, meaning you can prevent it from being composted naturally. if you really want to, you know, uh, dispose of the frame, um, it will biodegrade much faster than any other material that bicycle frames are made of.
[00:18:22] So yeah, the, the renewable aspect, the low energy content of it, it’s, it’s utterly the best you can imagine. And we’re kind of waiting for the world to finally get serious about global warming and start to have some economic incentives for buying products that are in fact, uh, good for the environment. Uh, we haven’t seen that yet, but we’re kind of holding out and hoping that happens.
[00:18:49] And then we’ll see probably some significant growth in the bamboo adoption in the bicycling world.
[00:18:57] Randall: I want to plant a seed that, that, uh, to germinate in my head, which is this idea of bamboos being the ideal material for kind of more mainstream, uh, utility bicycles and recreational bicycles. really it’s a matter of the unit economics in economies of scale and consistency of material, which you could make uniform by having, uh, having controlled grow conditions and things like that.
[00:19:23] Um, but it could be a very localized industry to anywhere where bamboo grows. this could be produced, which reduces transportation costs reduces, you know, issues of inventory carrying and all these things. Um, so let’s, let’s park that I want to ask you more about those, about the economics of bamboo in a side conversation to see if there’s, you know, explore there.
[00:19:45] Craig Calfee: well, there is. I mean, that’s, that’s what we did in Africa. Same concept is as why, why would bamboo work in Africa better than the imported bikes from China? So that was, that was the whole thing around that.
[00:19:59] Randall: Ah, I love it. All right. So though, there will be a bamboo episode folks. Uh, we’re going to, going to continue cause there’s a lot of ground to cover here. so next steps you’ve done done the first carbon frame and the tour de France, uh, carbon frames is up and running. You’ve started getting into bamboo, what was next,
[00:20:18] Craig Calfee: Um, then lots of smaller developments, which become really important to us from a business perspective, uh, fiber tandem, we built the first one of those. And then we went to a lateral list, tandem design, and it’s pretty optimized at this point. So we’re, I would say we are the leader in the tandem world in terms of the highest performance, tandem bikes, uh, and then re repairing of carbon frames.
[00:20:47] That was a big one, uh, which we were kind of pushed into by customers. And other folks who heard that we could repair the Cathy frames and they would set a call up. And literally we had a, an in one inquiry per week, if not more, more often about like a colonoscopy that this guy wanted to repair and he heard we could do it on ours.
[00:21:10] And we’re like, well, by a Calfee don’t, you know, I’m sorry, but we can’t repair somebody else’s frame. You’ll have to buy one of ours. And then you’ll know that you crash it, we can repair it for, he was trying to make that a, a a advantage for our brand, but we couldn’t really, you know, do that. So, uh, we said, well, if we can’t beat them, we’ll repair them.
[00:21:32] And we repaired a first and then some specialized, I think, after that. So we, we accepted repair jobs and pretty soon it became about a third of our, our business. And it’s, uh, of course now lots of other people repair frames, but, uh, we started doing that in 2001 or something and, and we’ve been doing it ever since.
[00:21:58] And it’s, that part has been really interesting to see, because we get to literally see the inside of everyone else’s frames and look at the weak points. You know, they often show up on, on people’s frames and get asked to fix them or even redesign them at that point. So that’s been really interesting to, to me as a technician,
[00:22:21] Randall: and want to come back to this in a second, but before we lose it, what is a lateralis tandem design?
[00:22:27] Craig Calfee: uh, that, so traditional tandems had a, a tube that went the head tube, usually straight back down towards the dropouts or or bottom bottom bracket. And it’s, it’s a way to stiffen up a frame. That’s inherently not very stiffened torsion. But, uh, with composites, you can orient the fiber, uh, in torsion to make a tube significantly stiffer and torsion than say a metal tube of similar weight.
[00:22:57] So we were able to go a little bit bigger diameter and more fiber in the helical angled orientation and make a tandem, uh, stiff enough and torsion and get rid of that tube. And for a carbon fiber frame, that it was really important because number of times you have to join the tube, the more expensive it is or the more labor content there is. So we were able to reduce our labor content, make the frame lighter and make it stiffer all at, in one design change. So that was a big, a big revelation. And now I most of them have copied that design. So it’s, uh, it’s, that’s another time where we, we did something that, that, uh, now became the standard.
[00:23:43] Randall: Yeah. One of many from what I’ve observed in a written the history. Uh, so around this time, or shortly after you started the repair business, you started doing some pretty, pretty wild frames in terms of pushing the limits of what was possible when we talk about that.
[00:24:01] Craig Calfee: Yeah. Yeah, we did. We’ve done a lot of different types of frames, uh, mostly for show, but, um, like the north American handmade bike show is a great venue for just doing something way out of left field. Um, we did, uh, a bamboo bike made all out of small diameter, bamboo. Um, it’s I only made one because it was a total pain in the ass to make.
[00:24:26] Uh, and it was also kind of inspired by the, a request from a guy who was not only a fan of bamboo, but he was a fan of molten style bikes. Those are the trust style frames with small wheels. So we built one of those and. With the only small diameter bamboo, and we built another one that was, uh, a real art piece.
[00:24:49] So just having fun with that from a, you know, completely artistic direction is a lot of fun for me because that’s my formal training. I went to art school and learned about different materials and, and art and composition. Uh, and I was into the structure of materials and how they, they relate to each other.
[00:25:12] And my art was more of a forum file form follows function, kind of inspiration. And, uh, so some bikes that I’ve made were, are not terribly practical, but just explore the, the limits of structure. So another bike I made, uh, we call it the spider web bike, which was literally a, a bike made of just carbon fiber strands.
[00:25:36] No tubes. And it, it was kind of wild looking and a collector ended up buying it, which is really cool. But you look at this thing and you just couldn’t imagine that it, it, you could actually ride it, but, uh, it actually does ride fairly well. It’s a bit fragile if you crash it, it would be kind of dangerous, but you know, stuff like that.
[00:25:55] I like to do that occasionally.
[00:25:59] Randall: I think of, uh, like biomorphic design or like hyper optimized design that maybe doesn’t have the resiliency, but very strict parameters will perform higher than anything else that you could, you could create.
[00:26:12] Craig Calfee: absolutely. Yeah. Those are really fun. I’m really inspired by natural forms and, uh, you know, the, the, some of the new computer aided techniques we’re designing are, uh, rattled in those lines. so, yeah, I follow that pretty closely.
[00:26:28] Randall: a little sidebar. Um, I don’t know if you’ve, uh, no of, uh, Nick Taylor, the guy who created the, Ibis Maximus in front of the mountain bike hall of fame.
[00:26:40] Craig Calfee: Um, no, I don’t think so.
[00:26:43] Randall: I’ll introduce you to his work at some point, but he’s another one of these people who, very avid cyclist is not in the bike industry, but is. There’s a lot of trail building and alike and isn’t is a sculptor really focused on, the form of, uh, you know, biological shapes and materials and, and things of this sort.
[00:27:02] Uh, I think that there’s a lot, uh, I’m actually curious more into your, your non bike artistic work for a moment. Uh, and, and how that got infused into your work with the bike.
[00:27:18] Craig Calfee: yeah, so I haven’t done a lot of, you know, just pure, fine art sculpture in a long time. But when I was doing that, it was. a lot of things that would fool the eye or, um, some material and, and push it to its limit. So I was doing stuff that was, um, uh, you know, trying to create a, almost like a physical illusion, not just an optical illusion, but a, but a physical illusion or like, how could you possibly do that kind of thing?
[00:27:54] And that was a theme of my sculpture shortly after Pratt. So for example, just take one example of a sculpture that I got a lot of credit for in classes at Pratt, it was a, a big block of Oak. It was a cutoff from a woodworking shop. It’s about a foot in, let’s say a foot cube of Oak. And I would, um, so I, I, uh, raised the grain on it with a wire brush and then I blocked printed on Oak tag page.
[00:28:26] Um, some black ink on rolled onto the Oak block and made a river, basically a print off of each face of the, of the block. And then I carefully taped that paper together to simulate a paper block of the Oak chunk that I I had. now I had a super light paper version of the Oak block. And then I hung them on a balance beam, which I forged at a steel, but the hanging point was way close to the piece.
[00:28:57] And if you looked at it from three feet away, just, your brain would, just hurting because you couldn’t figure out how is this even possible? And because it really looked amazing, super hyper real. Anyway, it just looked amazing and it was fun to get the effect of how the hell did that. Did he do that?
[00:29:18] What’s what’s the trick here. There’s something going on. That’s not real. Or it’s. Uh it’s not physically possible. And I kind of got that feeling with the carbon fiber bike. When we, when we built the first bike, everyone would pick it up and go, oh, that’s just too light. It’s not even a bike. It’s a plastic bike it’s going to break instantly.
[00:29:39] So that was sort of a relation from, from those days to the, to the bike.
[00:29:44] Randall: You ever come across Douglas Hofstadter’s book, Godel, Escher Bach.
[00:29:49] Craig Calfee: No, but I’d be interested to read it.
[00:29:51] Randall: Definite short Lister. Um, uh, you’ve come across MC Escher, of Yeah. And are there any parallels or any inspiration there?
[00:30:01] Craig Calfee: Um, not very direct, I’d say. Um,
[00:30:08] Who
[00:30:08] Randall: your, who your inspirations or what, what would you say your creative energy is most similar to?
[00:30:14] Craig Calfee: I’d probably, I’d say say Buckminster fuller.
[00:30:17] Randall: Mm,
[00:30:17] Craig Calfee: Yeah. I mean, I studied his work in depth, you know, not only the geodesic dome stuff, but also his vehicles, the dime on vehicle the, yeah. So there’s, there’s a bunch of stuff that he was involved with that I’d say, I’m parallel with as far as my interest goes,
[00:30:37] Randall: what books should I read?
[00:30:39] Craig Calfee: all of them.
[00:30:42] Randall: Where do I start? If I have limited
[00:30:44] time
[00:30:45] Craig Calfee: Yeah. It’s a tough one. He’s actually really difficult to read too. His writing is not that great. I pretty much look at his, uh, his design work more than His writing
[00:30:56] Randall: Okay. So who’s book whose book about Buckminster fuller. Should I read?
[00:31:01] Craig Calfee: good question. I’ll, I’ll catch up with you on that later because there’s few of them that they’re worth. It’s worth a look.
[00:31:07] Randall: awesome. Awesome. Awesome. Um, let’s talk about 2001. you’re a dragon fly.
[00:31:15] Craig Calfee: Yeah, the dragon fly was an interesting project. It was so Greg Lamanda had asked me, like, I want an even lighter bike. He was constantly pushing on the technology. And I said, well, there are some really expensive fibers that are starting to become available, but, um, you know, this would be a $10,000 bike frame and, you know, it’s only going to be a half a pound lighter.
[00:31:40] And he said, well, I don’t care. I just, you know, I w I need it for racing. I mean, um, you know, when, when I’m climbing Alpe d’Huez with Miguel Indurain and if he’s got a lighter bike than I do, then I’m just going to give up, you know, in terms of the effort. So he needs to have that technical advantage, or at least be on the same plane.
[00:32:02] So the reason why he’d spend, you know, $5,000 for a half a pound, a weight savings was pretty, pretty real. So, but it took until about 2000, 2001 after he had long retired to, um, really make that happen. So the fibers I was talking about are really high modulus fiber that was very fragile, too brittle, really for any use.
[00:32:29] So we came up with a way to integrate it with, um, boron fiber. Uh, it actually was a material we found, uh, special specialty composites out of, uh, out of Rhode Island. Uh, they, uh, do this co-mingled boron and carbon fiber, uh, hybrid material, which was, um, they were looking for a use cases for it and the bicycle was one of them.
[00:32:58] So, uh, we built a prototype with their material and it turned out. To be not only really light and really strong, the, the boron made it really tough. So carbon fiber has, uh, the highest stiffness to weight ratio, intention of any material you can use. boron is the highest stiffness to weight ratio in compression as a, as a fibrous material that you can integrate into a composite. So when you mix them, you now have a combination of materials, that are unbeatable.
[00:33:35] Randall: Like a concrete and rebar almost, or, quite.
[00:33:40] Craig Calfee: I’d say that’s a good, um, for composites in general, but now we’re talking about the extreme edge of, of performance, where, um, looking at the, most high performance material certain conditions, versus tension. These, these are conditions that are existing in a bicycle tube all the time.
[00:34:07] So one side of the tube is compressing while the other side is intention as you twist the bike, uh, and then it reverses on the, on the pedal stroke. So it has to do both now. Carbon fiber is quite good at that, but compression it suffers. And that’s why you can’t go very thin wall and make it, um, withstand any kind of impact because it’s, it’s got a weakness in it’s, um, compressive. So, uh, it’s, uh, it doesn’t take a break very well either. So boron on, the other hand does take a break very well, and it’s incredibly high compressive strength to weight ratio and compressive stiffness to weight ratio. are two different things by the way. So when you combine those into a tube, it’s pretty amazing.
[00:34:57] Uh, they’re just really quite expensive. So we came up with the dragon fly, um, in 2001 and it was at the time the lightest production bike yet it also had the toughness of a normal frame. And that’s that’s right around when the Scott came out, which was a super thin wall, large diameter, uh, carbon frame that was really fragile.
[00:35:23] Um, so that was sort of a similar weight, but not nearly as tough as, uh, the dragon fly.
[00:35:34] Randall: For well, to go a little bit deeper on this. So what is the nature like? What is the nature of the boron? Is it a, like, is it a molecule? Is it a filament? So you have, you have carbon filaments is the boron, um, you know, is that, are you putting it into the resin? How is it? Co-mingled.
[00:35:51] Craig Calfee: It’s a, it’s a filament, basically a super thin wire.
[00:35:56] Randall: You’re essentially co-mingling it in when you’re creating the tubes and then using the same resin to bond the entire structure together.
[00:36:04] Craig Calfee: That’s right.
[00:36:05] Randall: Got it. And this, so then this is, uh, if you were to add then say like to the resin separately, it would be a compounding effect. Um, I don’t know if you have, uh, mean, I assume you’ve done some stuff with graphene.
[00:36:19] Craig Calfee: Yeah. Graphing graphing is a really great material. It does improve the toughness of composites. Uh, it’s again, also very expensive to use, uh, in a whole two. Usually it’s used in smaller components, uh, not so much on the whole frame, uh, and it, and it’s, um, it’s best, uh, uses in preventing the of cracking.
[00:36:46] So it stops the micro cracking that starts with a failure mode. And that that’s a great, thing. But if your laminate is too thin to begin with that, all the graphing in the world, isn’t going to help you. So for really minor wax it’ll help, but for anything substantial, it’s going to break anyway.
[00:37:08] So you have to start out with a thick enough laminate get the toughness that you’re looking for. Uh, graphene is really great for highly stressed areas, which might start cracking from, uh, fatigue or just the design flaw of a stress concentration. So it’s got a number of purposes. Uh, it’s great for, uh, like pinch clamp areas, you know, places where the mechanical, uh, stress is so high on a, on a very localized area.
[00:37:37] Um, so yeah, graphene is wonderful. We didn’t get into it too much because, um, it’s just, it would just, wasn’t practical for our applications and how we make the frames, but, uh, some companies have started using graphene and it’s, it’s pretty interesting stuff.
[00:37:52] Randall: We did some experimentation with it early on in our looking at it for the future. my understanding is. You know, I haven’t gone too deep into like the intermolecular physics, but it’s essentially like you have a piece of paper and if you start tearing the paper that tear will propagate very easily.
[00:38:09] then the graphene is almost like little tiny pieces of tape. Randomly distributed, evenly distributed across the material that makes it so that that fracture can no longer propagate in that direction. And it has to change direction where it bumps into another graphene molecule and the graphing, essentially when we tested it was doubling the bond strength of the resin.
[00:38:30] So in terms of pulling apart different layers of laminate, then, um, increasing the toughness of say, uh, a rim made with the exact same laminate in the exact same resin with, 1% graphene per mass of resin increasing the toughness of that rim structure by 20%.
[00:38:50] Which is pretty
[00:38:50] Craig Calfee: That’s correct.
[00:38:51] Randall: The challenges that is that it lowers the temperature, uh, the, the glass suffocation points resin. so, you know, a rim is like, you know, there are, if you’re gonna put it on the back of your car, you know, that’s not a normal use case when you’re riding, but, you know, it’s, it’s something that just makes it less resilient to those towards sorts of, you know, people put on the back of the car too close to the exhaust and they melt the rim.
[00:39:17] So we’re having to experiment with some high temperature residents that have other issues.
[00:39:22] Craig Calfee: Oh, yeah. Yeah. That’s rims are a great place for graphing, just cause they’re in a a place where you’ll have some impacts, but yeah. Temperature management is an issue. Um, yeah, that’s the high temperature residents are, are another area that, that, uh, we’re experimenting in, uh, wrapping electric motor, uh, rotors with, with a high temperature resonant carbon wrap.
[00:39:46] that’s a whole nother area, but I’m familiar with that stuff.
[00:39:49] Randall: Which we’ll get into in a second, park park, that one. Cause that’s a fun theme. yeah. And I’m just thinking about a rim structure. It seems like boron on the inside graphing on the outside, um, deal with high compressive forces between the spokes and then the high impact forces on the external, will
[00:40:07] Craig Calfee: the material we use is called high bore. You can look that up. H Y B O R and there they’re actually coming back with new marketing efforts there. They, I think the company got sold and then, um, the new buyers are, are re revisiting how to, to spread the use of it. So might be real interested in supporting a rim project.
[00:40:30] Randall: mm. Uh, to be continued offline. Um, all right. So then we’ve got your carbon fiber repair surface. We talked about the dragon fly. Um, it’s a great segue into engineering and design philosophy. let’s talk about that
[00:40:47] Craig Calfee: Yeah. Um, well it’s, to me, it’s all about form follows function and, uh, when something works so well, functionally, it’s gonna look good. That’s uh, that’s why trees look great just by themselves, uh, that that’s, you know, coming back to the natural world, you know, that’s why we have a Nautilus shell for, uh, for our logo.
[00:41:12] It’s the form follows function. Aspect of that just makes it look beautiful. For some reason, you look at something from nature, you don’t really know why is it beautiful? Well, the reason is the way it’s structured, the way it’s evolved over millions of years. Has resulted in the optimum structure. So for me, as a, as a human being artificially trying to recreate stuff, that’s been evolved in nature.
[00:41:39] Um, I look closely at how nature does it first and then I’ll apply it to whatever I’m dealing with at the moment. And so that’s how I, that’s how I design stuff.
[00:41:50] Randall: there’s a, the Nautilus shell example, like, you know, the golden ratio and the way that, really complex systems tend to evolve towards very simple, fundamental, primitives of all design
[00:42:04] Craig Calfee: Yeah. Yep. Yeah. There’s some basic stuff that, that seemed to apply everywhere.
[00:42:10] Randall: So with your carbon fiber repair service, so you started to see some of the problems with that were emerging with these, um, large tube thin wall designs that were being used to achieve a high strength or sorry, a high stiffness to weight, but then compromising in other areas.
[00:42:28] So let’s talk about that.
[00:42:30] Craig Calfee: Yeah, it’s um, you know, designing a carbon fiber bike is actually really quite difficult. There’s so much going on. There’s so many, uh, things you have to deal with high stress areas that you can’t really get around. there’s a lot of constraints to designing a good bicycle frame. Um, and then you’re dealing with the tradition of, of how people clamp things on bikes, you know, stem, clamps, and seed post clamps, and, uh, you know, th that type of mentality.
[00:43:04] It’s still with us with the carbon, which is carbon doesn’t do well with. So a lot of companies struggle with that and they’ll come up with something on paper or in their CAD model. And their finite element analysis sort of works, but, and then they go into the real world and they have to deal with real situations that they couldn’t predict in the, the computer.
[00:43:29] And they get a problem with, uh, you know, a minor handlebar whacking, the top tube situation, which shouldn’t really cause your bike to become dangerous. But in fact, that’s what happens. So you’ve got, um, you know, uh, weak points or vulnerabilities in these really light frame. And if you’re not expected to know what the vulnerability is as an end-user and you don’t know that if you wack part of the bike and in a minor way that you normally wouldn’t expect to cause the frame to become a weak, then the whole design is a question. So you have to consider all these things when you decide to bike. And a lot of companies have just depended on the computer and they are finite element analysis too, to come up with shapes and designs that, uh, are inherently weak. And, um, people get pretty disappointed when they’re, when the minor is to of incidents causes a crack in the frame.
[00:44:37] And if they keep riding the bike, the crack gets bigger. And then one day, you know, I mean, most people decide to have it fixed before it gets to be a catastrophic but, uh, you know, it gets expensive and, uh, You know, it’s, sad. Actually, another motivation for getting into the repair business was to save the reputation of carbon fiber as a frame material.
[00:45:03] You know, these types of things don’t happen to thin wall titanium frames. You know, a thin wall titanium frame will actually withstand a whole lot more abuse than a thin wall carbon frame. So it’s just hard to make diameter thin wall titanium frames that are stiff enough and not without problems of welding, you know, the heat affected zones.
[00:45:26] So carbon fiber is, is a better material because it’s so much easier to join and to, to mold. But if you, you have to design it properly to, to withstand normal abuse. And if you’re not going to do that, then there should at least be a repair service available to keep those bikes from going to the landfill.
[00:45:45] So frequent. And so that’s what we do we, we offer that and we even train people how to carbon repair service. So that’s, um, that’s something we’ve done in order to keep bikes from just getting thrown away.
[00:46:01] Randall: uh, I think I’ve shared with you, I’m in the midst of, uh, doing, uh, uh, a pretty radical ground up design, which is way off in the future. So I’ll be picking your brain on that, but it immediately makes me think of the inherent. Compromises of current frame design and manufacturing techniques, including on our frame.
[00:46:20] And in our case, the way we’ve addressed that is through not going with lower modulates carbon, you know, S T 700, maybe some T 800 in the frame, then overbuilding it order to have resiliency against impacts. But then also these sorts of, um, micro voids in other imperfections that are in inherent process of any, uh, manufacturing, uh, system that involves handling of materials in a complex, you know, eight, uh, sorry, 250 a piece, you know, layup like there’s, this there’s even that like human elements that you have to design a whole bunch of fudge factor into to make sure that when mistakes are made, not if, but when mistakes are made, that there’s so much, uh, overbuilding that they don’t end up in a catastrophic failure.
[00:47:10] Craig Calfee: that’s right. Yeah. Yeah. You have to have some safety margin.
[00:47:15] Randall: And the Manderal spinning process that you were describing essentially eliminates a lot of that in you’re starting to see, I mean, with rims, that’s the direction that rims are going in, everything is going to be automated, is going to be knit like a sock and frames are a much more complex shape. Um, but you’re starting to see, uh, actually probably know a lot more about the, the automation of frame design than I do.
[00:47:35] Um, what do you see? Like as the, as the end point, at least with regards to the, um, like filament based carbon fiber material and frames, like where could it go with technology?
[00:47:50] Craig Calfee: the, the, um, robotics are getting super advanced now and there’s this technique called, um, uh, they just call it fiber placements or automated fiber placement, which is a fancy word for a robot arm, winding fiber, you know, on a mandrel or shape, uh, and then compressing that and, uh, know, molding that.
[00:48:14] So it’s, it’s where your, a robot will orient a single filament of carbon fiber. Uh, continuously all around the, uh, the shape that you’re trying to make. They do that in aerospace now for a really expensive rockets and satellite parts, but the technology is getting more accessible and, uh, so robotic trimmers are another one.
[00:48:42] So we’re, in fact, we’re getting ready to build our own robotic arm tremor for a resin transfer, molded parts. That’s where the edge of the part that you mold gets trimmed very carefully with a router. And, but imagine instead of just a router trimming an edge, you’ve got a robot arm with a spool of fiber on it, wrapping the fiber individually around the whole structure of the frame.
[00:49:10] Uh, no, no people involved just, you know, someone to turn the machine on and then turn it off again. So that’s kind of coming that that is a future. Uh, it hasn’t arrived yet, certainly, maybe for simpler parts, but a frame is a very complex shape. So it’ll take a while before they can get to that point.
[00:49:30] Randall: It having to, yeah. Being able to Uh, spin a frame in one piece is, seems to be the ultimate end game.
[00:49:43] Craig Calfee: Yeah. I think we need to, I think the, the, uh, genetically modified spiders would be a better way to
[00:49:50] go
[00:49:50] Randall: Yeah, they might, they might help us the design process.
[00:49:56] Craig Calfee: Yeah. Yeah. Just give them some good incentives and they’ll, they’ll make you set a really incredibly strong, you know, spider wound.
[00:50:05] Randall: Well, it does. It speaks to the, the, the biggest challenge I see with that, which is you have to go around shape. so if you’re going through a frame, like it’s essentially the triangle. And so you need some way to like hand off the, the S the filament carrier from one side to the other constantly.
[00:50:27] you’d just be able to spin it. You know, it would be pretty straightforward. So maybe the frame comes in a couple of different sections that get bonded, but then those don’t form a ring. And so you can, you know, you can move them around instead of the machine order
[00:50:41] Craig Calfee: Well, there’s these things called grippers. So the robot grip sit and then another arm grip know let’s go and the other arm picks it up. And then there’s like in weaving, there’s this thing called the flying shuttle, which invented. That’s where the shuttle that, the war
[00:50:59] Randall: Your ancestors were involved with flying shuttle.
[00:51:02] Craig Calfee: Yeah.
[00:51:02] Randall: That’s one of the, uh, all right. That’s, that’s a whole other conversation.
[00:51:07] Craig Calfee: Yeah, a really interesting, I mean, it’s the Draper corporation. If you want to look it up,
[00:51:13] um
[00:51:13] Randall: I
[00:51:13] Craig Calfee: know
[00:51:14] they were the manufacturing made the looms back in the industrial revolution in the Northeast
[00:51:21] Randall: I’m sitting currently in Waltham, which was one of the first mill cities, um, not from Lowell.
[00:51:28] Craig Calfee: Yeah. So all those mills were where our customers and they would buy the Draper looms. Um, and they were automated looms with a flying shuttle was a big deal Uh back then. And so they, they made a lot of, of those looms and, and that’s basically what sent me to college with a trust fund. So
[00:51:49] Randall: You’re a trust fund, baby.
[00:51:51] Craig Calfee: Yep.
[00:51:51] Yep
[00:51:53] From vendors.
[00:51:55] Uh
[00:51:56] but that’s yeah, that’s the world I, I came out of. And, so the, the idea of taking a spool of material and handing it off as you wrap around something is really not that difficult.
[00:52:08] Randall: Okay. So then you can do it in a way that is resilient to probably 10,000 handoffs over the course of weaving a frame and you can expect that it’s not going to fail once.
[00:52:19] Craig Calfee: That’s right Yeah
[00:52:20] It
[00:52:20] Randall: All then that, that’s
[00:52:22] Craig Calfee: the hard part, the hard part is dealing with the resin and the, and the, uh, forming and the getting a nice surface finish. That was where the harder.
[00:52:31] Randall: Yeah. And, uh, uh, I’m thinking about, uh, space X’s attempts to create a giant, uh, carbon fiber, uh, fuel tank. And they actually had to do the, um, the heating the resin at the point of, uh, depositing of the filaments.
[00:52:52] And
[00:52:52] you know, that’s a really challenging process because you can’t build an autoclave big enough to contain a fuel tank for a giant rocket bicycles don’t have that issue, but
[00:53:01] Craig Calfee: right. Yeah. The filament winding technique, which is how all those tanks are made is, is pretty amazing in the large scale of those, those big rockets is phenomenal. I mean, a couple of places in Utah that make those, and it’s just seeing such a large things spinning and, uh, wrapping around it rapidly is quite inspiring.
[00:53:26] Randall: Yeah. It’s very, very cool stuff. And that’s, again, a whole another thread about the, uh, the Utah based, uh, composites industry that got its start in aerospace, you know, advanced aerospace applications, which NV and others came out of. They used to be edge which you worked with. NBU designed their tubes early on.
[00:53:43] Right.
[00:53:44] Craig Calfee: W well, yeah, the poles history behind envy and quality composites back in late eighties, literally, uh, when I first came out to, uh, actually I was still, think I ordered them in Massachusetts and took delivery in California, but it was a quality composites and out of Utah, uh, Nancy Polish was the owner of that.
[00:54:06] Also an MIT graduate who, um, who started a roll wrapping carbon fiber in tubular forum. And I’m pretty sure we were the first roll wrapped carbon tubes, uh, for bicycles that she made. And, um Uh, evolved to, uh, edge composites. So they, so quality composites became McClain quality composites, and then McLean, the guys who broke away from that went to start envy or edge, I guess, which became envy.
[00:54:40] So yeah, those same guys brought that technology and we’ve been the customer ever since. And now there’s yet another spinoff. The guys who were making the tubes at envy spun off and started their own company, uh, in a cooperative venture with envy. So let them go basically. And, uh, we’re working with those guys.
[00:55:01] So it’s just following the, the top level of expertise.
[00:55:06] Randall: very interesting stuff. Um, so, so where else do we go in terms of the, I mean, this is about as deep a composite deep nerdery, as we can get in, into composites and so on. And, uh, given that we’re already here, we might as just, you know, dig ourselves deeper.
[00:55:25] Craig Calfee: Yeah. Um, sir, just on the roll wrapping, the thing that, um, I remember one of the cool innovations that Nancy came up with was the double D section, um, tube where she would roll wrap two D shaped tubes, stick them together and do an outer wrap on the outside. So it was a efficient way to do a ribbed tube or a single ribs through the middle. She pretty much invented.
[00:55:53] Uh, we started doing something with that, um, change days, uh, to get more stiffness out of a change day. But, um, I just, some reason that image flashed in my mind about some of the innovative stuff that been going on that people don’t really see it’s. And that’s what I’m saying before where the, uh, technology of composites has, um it’s got a long way to go and it’s, there’s all kinds of stuff going on that are, are, is brand new.
[00:56:23] Uh, most people people don’t see it cause it’s all process oriented more than product oriented. But for guys like me, it’s really fast.
[00:56:34] Randall: Yeah, it reminds me of, um, a technology owned by a Taiwanese carbon frame manufacturing, pretty large-scale tier one that I’d spoken to where they’re doing, uh, that bracing inside of the forks. don’t think they’re doing anything especially advanced in terms of how it’s manufactured.
[00:56:54] I think they just have a, uh, the, the inner, um, you know, whether it’s a bag or it’s a, you know, EPS insert. And then they’re just bridging, uh, between the two walls of the, uh, of the tube of the, the fork leg, uh, with another piece of carbon that gives it more lateral structure zero, uh, impact on the, um, for AFT compliance, which is a really technique.
[00:57:21] Craig Calfee: that sounds like Steve Lee at
[00:57:24] Randall: Uh, this was YMA.
[00:57:27] Craig Calfee: Oh, okay.
[00:57:28] Randall: Yeah, the gigantic folks. I haven’t, I don’t know if I’ve interacted with them yet, but, um, but yeah, well,
[00:57:35] Craig Calfee: Yeah, some amazing innovation coming out of Taiwan. They’re there. They’re so deep into it. It’s, it’s a fun place to go and, and see what they’re up to.
[00:57:47] Randall: this actually brings me back to, um, I, I did had a conversation with over with Russ at path, less pedaled, and was asking like, you know, tell me about the quality of stuff made, made over in Asia. And I was like, well, you know, it’s generally best to work with their production engineers because they’re so close to the actual manufacturing techniques and they’re the ones innovating on those techniques.
[00:58:10] And in fact, um, you know, even specialized up until recently did not do carbon fiber in. outsource that, you know, they, they do some of the work in house, but then the actual design for manufacture and all that is being done by the factories and rightfully so the factories know it better, being close to the ground though, dealing with someone with yourself, you’re someone who could go into a factory and be like, okay, let’s, let’s innovate on this.
[00:58:35] Craig Calfee: Yeah.
[00:58:36] Yeah.
[00:58:37] Randall: so then 2011, um, first production, gravel bike.
[00:58:45] Craig Calfee: Uh, yeah. Yeah. We came up with the, uh, adventure bike, we call it, um, it was also the first one that did the, uh, six 50 B uh, tire size that can be used with a 700 by 42 or So mixing, know, going bigger tire on a slightly smaller rim on the same bike as you’d run a 700 C and, uh, 35 or 40 millimeter tire. Um, yeah, so the adventure bike has been. Uh, a real fun area for us as far as, uh, just developing a, do everything. Be everything, bike
[00:59:24] Randall: it’s. And the geometry of that was kind of an endurance road geometry, right
[00:59:28] Craig Calfee: that’s
[00:59:29] right. It’s a road bike effectively, but with a few, a few, uh, tweaks for riding off road.
[00:59:36] Randall: So then this, this word, gravel bike is kind of muddled.
[00:59:39] Um, I never liked it, frankly. Uh, it’s a marketing term. I remember it specialized when we were doing the, the diverse, um, you know, it was still kind of honing in on what these bikes were. Uh, but you could argue that like, you know, you know, everyone’s road bike was a gravel bike. When you just put the biggest tires that would fit and write it on dirt.
[00:59:57] But this concept of a one bike, it seems to be what you’ve planted. But you can have a single bike that will be your road, bike, perform handle, give you that, that experience when you put road wheels on, but then you can put these big six fifties on there and have a, you know, an off-road crit machine that is highly competent in, in rough terrain.
[01:00:16] And so, so yeah, that, and that’s very much my design philosophy as you know, as well, you know, fewer bikes that do more things.
[01:00:24] Craig Calfee: Yeah. We have this. Kind of a marketing phrase for, you know, how the end plus one concept where, you know, how many bikes do you even need? Well, one more than what you’ve got. Well, we do the N minus one concept with our mountain bike, which can also be a gravel by ache or a bike, but it’s, uh, it allows you to change the head tube angle and, and use different, uh, fork travel suspension forks on, on the same frame.
[01:00:55] Uh, and of course, swapping wheels out is, is always a thing. So yeah, the end minus one concept where we just need less stuff, you know,
[01:01:04] Randall: So I reinvented that when I started thesis, he used to say like, and, minus three, it replaces road, bike, your gravel bike, your road, bike, your cross bike, your, um, light duty cross country bike, uh, your adventure bike actually as well, you know, load these things up. yeah, very much a philosophy that, uh, I think it’s so good that the, its efforts to come up with new, subcategories, for example, by having gravel bikes now run oversize 700 wheels and extending the geo and going with these really slack head angles in order to accommodate that wheel size.
[01:01:40] I actually think that the form, the form that things want to evolve towards is actually what you created in the first place, which is the one bike that does all the things and does them well. And depending on the wheels you put on them, um, we’ll do we’ll, we’ll transform. Uh, and you know, we’ve, we’ve talked a little bit about geo changing, um, You know, and things like this, which you have a bike that, that does that.
[01:02:03] And why don’t we talk a bit about that in the technology behind it?
[01:02:08] Craig Calfee: The SFL, you mean we use the geometry of the head tube and the bottom bracket to, uh, to accommodate what you’re using it for? Yeah, the concept there is to, if you’re on a long ride to be able to change the geometry of your bike mid ride. So with an Allen wrench, you, uh, basically swap these flip plates out on your head to varia.
[01:02:32] And so you climb, you can climb with one geometry with another. And to me, that’s, that’s really fun because the climbing, you, if you’re climbing up a a long steep climb on a bike that you’re going to descend back down on, uh, you really don’t want the same geometry it’s, you’re compromising and one or the other, either climate.
[01:02:55] Or it descends great. It’s rarely both, or really can’t possibly be both. Cause they’re just doing two different things. So if you can swap out these flip plates and change the head tube angle, which is really all you need at that point, um, you have a bike that climbs great and descends. Great. So for me, that was the goal of, uh, just making a better mountain bike. Um, you know, the fact that it can be converted into other bikes for different disciplines is a whole nother angle. Uh, and you can even do that perhaps you wouldn’t do it the trail, but let’s say you show up, say you’re on a trip, an adventure, uh, maybe out to Utah, for example, where you’re riding slick rock, but you’re also going to go up, you know, into the mountains.
[01:03:45] Um, you’ll have you, you might want to have. Different fork travels or different for, uh, options. So you can bring a couple of different forks and swap out a fork, change your flip plates and have a bike. That’s awesome for slick rock. And then another one that’s awesome for, for the bike parks. So, you know, to me it would, but it’s only one bike and you know, you don’t need, you know, three bikes. So that, that just, uh, that’s the design result of a bike where you can change the head tube angle on,
[01:04:21] Randall: and the, in really how much head tube angle adjustment is there on there.
[01:04:25] Craig Calfee: uh, it’s a or minus four degrees
[01:04:28] Randall: that’s, that’s substantial.
[01:04:30] Craig Calfee: that’s a lot.
[01:04:31] Randall: Yeah.
[01:04:31] I mean, that’s transformative really. I work in increments of, you know, half a degree.
[01:04:36] Craig Calfee: Yeah. These are half degree increments, um, right now, uh, one degree, but we can easily do half degree increments. find that one degree is, is really. Um, especially when you have the option of, of tweaking the same bike. So reason we focus on these half degree increments on a production bike is to dial in the best compromise between two, two ways that it’s going to be used when you don’t need to compromise, you can go a full degree in the other direction and not worry about fact that it’s not going to perform as well, know, in super steep terrain because that flipped chip is not, uh, the right one for the super steep scenario.
[01:05:22] Just change it out or flip it over a T when you approach the really steep stuff. So yeah.
[01:05:29] Randall: applicable for mountain bikes, particularly because the, I mean, the slack, the long slack that, that have emerged in recent years make a ton of sense for mountain biking, especially descending, but when you’re ascending, it ends up being so slack that you get wheel flop, you get the front end, lifting the bike naturally wants to tilt back.
[01:05:49] You don’t have that on a gravel bike currently. And if you don’t, if you’re not adding a huge suspension fork, you’re never going to be descending terrain that is so technical that you need those slacked out angles. So it sounds like something that’s very much could be applied to gravel bikes, but that, you know, for the mountain bike application is actually pretty game-changing.
[01:06:06] Craig Calfee: Yeah, well on gravel bikes or adventure bikes, um, uh, it’s actually helpful if you’re, if you’re, let’s say you’re a roadie and you’re starting to go off road. And so you’re driving these gravel trails and then you’re starting to get into more interesting off-road excursions with that same bike, but your experience on steep terrain is limited because you’re, you know, you’re a roadie, you’ve your, all your muscle memory and all your bike handling memory comes from the road and a little bit of dirt road stuff.
[01:06:39] Now you’re kind of getting into serious off-road stuff and you want to try. a Uh, shortcut dissent, uh, you know, down something kind of crazy. Uh, let’s say, uh, you’re not very good at it in the beginning and you take your time and you, you don’t have a bike that can go that fast down, such a trail, then you change it out.
[01:07:00] As you get better at it, as you increase your skill level and your confidence level, might want to go a little faster. So you a bike that can go a little faster safely and go for that slack head angle, which is designed to get higher speed. So it’s great for evolving skills and evolving terrain as you start exploring more radical stuff.
[01:07:27] So that’s the other reason to do it.
[01:07:29] Randall: Yeah, that makes, that makes a lot of sense. And in fact, any, you know, what I’m working on going forward very much as a, uh, one of the core, you know, is, uh, being able to tailor the geometry, um, as close to on the fly as possible. Uh, you know, if you want it to be on the fly, you’re going to add a huge amount of added structure and complexity and weight, but having it be when you swap the wheels, there’s very little to do, you know, this sort of thing.
[01:07:57] Craig Calfee: Yeah. So yeah, the whole idea is to, is to be able to go and have really fun adventures after all I wrote the book on adventures, see, here’s, uh, this is a, this is the commercial part of our, our, uh,
[01:08:10] plug
[01:08:12] is, uh, this book I wrote about a trip. I took back in the, in the mid early eighties. Uh it’s it’s a kind of a.
[01:08:20] Randall: of a
[01:08:21] Craig Calfee: It has nothing to do with bikes, except that there is a section in there where I made a canteen out of bamboo in the Congo, but it’s a pretty crazy trip. And, uh, and I just called it adventures. It’s on amp. anyone wants to buy it.
[01:08:37] Randall: I will get a coffee.
[01:08:39] Craig Calfee: Yeah.
[01:08:42] Randall: Um, very, very cool. Um, we skipped over one, which is the manta, which is another interesting innovation
[01:08:51] Craig Calfee: Yeah. Suspension on a road bike. I mean, that’s a, I keep saying that’s going to be the future and it hasn’t happened yet, but I, I still believe that road bikes will be the main type of bike being written in the highest levels of racing.
[01:09:08] interesting
[01:09:08] Randall: So you think suspension versus say. Um, wide tubeless, aerodynamic, the optimized rims with a 30 mil tire run at lower pressures. You think the suspension has a sufficient benefit relative to that, to offset say the structural complexity or weight?
[01:09:25] Craig Calfee: Yes. So, uh, the big tire thing, trend towards bigger tires is really a trend towards suspension. It’s pneumatic suspension rather than mechanical suspension.
[01:09:39] Randall: Well, as our regular listeners know, this is a topic that’s very much near and dear to my heart. I talk often about the benefits of pneumatic suspension, so this will be an interesting place for us to stop and really dive in when we follow up in part two of this conversation which Craig and I will be recording on the Thursday after this episode is published. So if you’d like to participate in the conversation, please tag us in the ridership, direct your questions and comments our way, and we will try to incorporate them into part two. And of course, if you haven’t already come join us in the ridership, we’d love to have you and there’s a lot of innovation that will be happening there in terms of how we use new digital tools in order to facilitate the community that we want for offline connection exchange and experience.
[01:10:21] So with that until next time. It’s Craig would say here’s to getting some dirt under your wheels.