Cduro Epona: Innovative Carbon Fibre Mountain Bike | Bespoked Interview
Humphrey and Martin brought this wound carbon fibre Cduro Bike to Bespoked, Manchester, all the way from the Czech Republic. As the more confident English speaker of the two, Humphrey talked us through what gives this bike its unique look.
How do you say this brand name?
See-duro. Cduro Bikes.
How long has Cduro Bikes been going and where is it based?
So it’s based in Czech Republic. It’s the offspring of a composite engineering company that we work for. And so that company is called Compotech. Cduro, it’s probably been a brand for about three years, maybe four years, but this bike has sort of been slowly, slowly developed and now this year we are actively marketing it to be purchased.
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Does it have a name?
It does, it’s called the Epona. That is the name of a trail in the nearby mountains, near Sušice in the Šumava Mountains. The trail was named after the Celtic god, Epona, which is the god of travel and dreams and horses, apparently.
Oh, so we might refer to this as a ‘steed’, although that’s banned in the style guide! Tell us about the travel and geometry on this.
It’s a 160 rear travel, 170 on the front. [Hands over geometry chart]
Medium reach is 475mm or 500mm in a large, going all the way up to an XL at 535mm reach. Chainstay stays the same length. So basically the same rear triangle for all sizes. 450mm chainstays. Seat tube angle of 78 degree, apart from in the small, which is a 79 degree. And the head tube angle is a 64 degree throughout.
What’s the goal behind this? What kind of riding, or what are you hoping to bring to the mountain bike world through this bike?
So it came out firstly as a long, slack enduro star bike for the guys that we work with to ride the local trails, but also to race them. We have a small race team, who are the guys who build and work on production, and work in the office. And that was the original thing, but it’s become, let’s say, less slack and long to the geometry we have today, but it’s still pretty big, I’d say.
It’s aimed at long enduro days or long, let’s say, rough trail rides. And even, yeah, long travel trail bikes. Martin’s more of a downhiller, let’s say! So it’s quite broad, but we’re aiming more sort of not extreme enduro, let’s say. I mean, you can get 180mm travel on an enduro bikes these days! But the pedaling and the efficiency is pretty good. I would say very good. That’s due to the light weight and also stiffness that we have in the frame.
And so talk a bit about the construction and some of the kind of layups or whatever that you’ve done in order to achieve different characteristics at different points.
Compotech is a composite engineering company and composite technology company. So we’ve come from that direction and we are winding and placing fibres and we are able to optimise each tube to be the optimal bending and torsional stiffness. And then we take that step further with laying true axial fibres with our winding technology, which increases the stiffness to weight ratio over, let’s say, a standard wound design.
We’re getting quite technical now…. Most winding companies will do a cool axial wound fibres axial, but they’re actually about 6 to 10 degrees. And being able to actually place true zero degrees, you get an increase in stiffness compared to that.
I can see that there’s quite an unusual junction going on at these tubes so tell us about those?
That’s the next point is we’re winding the fibre in the first place. So let’s take that into the next step. We’ve developed this technology called ILT, which is Integrated Loop Technology. And that makes a continuous loop of fibre to create a junction between the connecting tubes. So the head tube and the seat tube can be fitted into this loop. And that means multiple things. Firstly, we are using a minimum amount of fibre for a connection, and it’s designed and optimised with FEA and everything to be the optimised amount of fibre we can use. And then minimal amount of hand labour to actually butt the tubes together and over laminate. So we’re not using manual labour to do that. It’s an automated process basically to create these loops. Obviously to bond them together it’s hand labour, but we’re not having to grind them by hand and then over laminate by hand and then sand that back by hand.
So you just make these sort of Spiderman web loop things and then stick the tubes in and a bit of adhesive to bond it all together?
Yeah, basically. And that is a process that we’ve developed as part of Compotech and CDuro is pushing that as a bike frame structure.
And I can see quite a lot of different patterns in the layout. There’s a sort of crisscross thing, there’s the more standard fibre crisscross, like standard version, and it almost looks like a viper on the top in there. So are those a product of the way you make it in order to deliver the functionality, or are they decorative?
No, nothing’s decorative in this. It looks nice, but it’s all functional basically. So the pattern of the fibre is based on the fibre optimised angles that we’ve used and so on the top tube here you can see the plus and minus, what are we saying, that is maybe 30 degrees. But either side of it is the axial fibre which is placed on the outside, which is the continual loop fibres. And then what we do is on each end we will do some loop fibres or hoop fibres which are 90 degree fibres and that is compressing and tensioning all those fibres. And then the finish is a tape so when you touch the surface you can feel that there’s been a tape wound around it, that’s just to consolidate and to remove any excess resin.
So in the end you don’t have a female mould for this part. There’s certain areas where we have used more traditional fabric hand lay-up parts like in the rear triangle, because we are winding tubes and generally when you do that they need to be straight tubes. We have to design everything around that process.
So in around the yoke and stuff, is that, that’s all still carbon fibre and there’s no metal buried in there or anything like that?
No, that’s all carbon fibre but we’ve created a junction there and that is hand laminated and we have to do that. There’s certain areas where we have to use a different process and this part here for joining the frame to the shock is a moulded component that we produce.
OK, so that shock mount there, that’s carbon fibre?
Yeah.
And then these joints here, that’s metal?
They’re all lugged aluminium. They’re machined outside and bought. So we’ve done various different things. I’d say one day we will produce it all in carbon but for the tolerances and the production at the moment it’s easier to get those parts produced.
And was there a particular part or area of the bike that was more challenging than the rest to get right? Or is it all a, I was going to swear, a screw with your head affair?
So, I mean, Martin is more involved in the nuts and bolts of the design and production process and I don’t know what he would say was most difficult. I know that he’s had troubles with various different things. I mean, there’s been lots of things. As engineers, we’ve come at this as a company that is doing B2B engineering parts and to actually get a product has been, that is the hardest thing I’d say. But on the technical side, yeah, the actual process, we’re really proud of how this process looks now from where it was. We started doing it six years ago and [some of that was] quite agricultural. We’ve played around with different moulding systems to do that, different, so if you imagine you have a 3D jigsaw of mandrel components inside when you’re doing it, winding the part. So to make that efficient but still look nice is something that they’ve worked really hard on. From the geometry side, that’s evolved and I know that but from the start, the original design of the rear pivot position, he was quite proud of how that sits quite forward and creating a progressive single pivot suspension kinematics.
Hhave you been to see Cornelius at Intend for these suspension parts by any chance?
Yeah, so these are actually carbon forks that Compotech is working on, collaborating with him. He showed the first prototypes last year at Eurobike. He will have them again this year, hopefully, next week. This is the sort of updated crown and yeah, I can’t say too much of what he’s planning on, it’s still in the process of prototyping and testing.
Right, well that’s enough, we can be teased! Is there anything else that we’ve not touched on that you would like to tell me about this bike?
I think generally the bike, the way we can choose the stiff tubes means we can go to thinner tube profiles and create something that almost looks like a steel bike. And that’s sort of the direction we want to go, where it’s not like your big fat carbon frame. It’s definitely different looking. I’m not saying it’s everyone’s cup of tea, but a lot of people like it. It’s quite, let’s say, industrial looking.
It’s got a slightly menacing edge to it, I think. Maybe it’s like, is it the black evil Spider-Man thing?
That’s the thing, we also want to leave it raw carbon. Because as you noticed, you’ve got a lot of patterns going on and it shows the layup and the rear triangle has been ground so it looks a bit more of a fuzzy pattern, whereas this is just the finish from the tape. It looks different, but it’s the same process, just been finished with a grinding process. Yeah, that’s how we want to leave it, but some people have asked for it painted.
I think they’re wrong, personally. But there we go!
It’s a light bike, it’s a stiff bike and it’s an interesting new technology. We’re engineers, so we’re really geeky on the technology of the carbon. But we’re really learning the process of trying to sell a bike. We’re saying frame weight is 2.2kg for a medium.
Right, well thank you very much for that.
Unique content like this takes time to create, and would normally be paywalled. But we’d like to support the independent builders and makers behind these bikes, and Bespoked. So you’re getting to read this for free. If you enjoy it, please consider joining us, and supporting what we do.
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