First Look & Interview: Gamux CNC Gearbox Bike At Les Gets

Pascal Tinner, CEO of Swiss bike brand, Gamux, swapped in for one of their injured racers to test a prototype bike on the Les Gets World Cup course last weekend. The bike is rather unique: it's CNC machined in one piece, uses a Pinion gearbox and a high pivot four-bar suspension design. World Cup photographer Ross Bell managed to grab an interview and photographs with Pascal and get the full scoop on the bike. I've edited the transcript of Ross's interview for you to read below, but here are the key details.




Interview between Ross Bell and Pascal Tinner

Ross Bell:
So Pascal, looks like you've been busy. What have you been working on here then?

Pascal Tinner:
Yeah. So this is a first prototype of a CNC milled downhill bike that we're working on - we're trying different stuff. You know, COVID, hasn't been easy on the bike industry, so it's hard to find tubes and other things to weld frames or produce basically. So we went down another route...
This is what we came up with. Now it's just validating all the simulations we've done in CAD or 3D and then taking this and making it into the next situation, I guess.



Ross Bell:
Yeah. So you guys started working on new bikes. What was it? Two, maybe three years ago?

Pascal Tinner:
Two years ago. Yeah.

Ross Bell:
This looks like a pretty big departure from the one you had last year.

Pascal Tinner:
Yeah. So the bike we had last year is not going away at this point. Just our main rider [Loris Michellod] has a torn ACL. So we took the opportunity with the current UCI regulations to inscribe myself, to be able to come test new things at World Cup level. You don't usually get those kinds of tracks anywhere else. So this is for sure, more towards future orientated in terms of frame production for us. We're just evaluating different things for maybe next year or the year after. The old thing isn't going away, that's a solid base and this is just where we are probably heading in the future.

Ross Bell:
What did you learn this weekend on the track then? It's a pretty wild one.

Pascal Tinner:
Yeah, it's a pretty wild one! She held up, nothing broke. So that's one thing that's always cool to see. And then mainly working on frame stiffness. It's quite impressive or quite obvious here when you have the slick roots what flex can do for you, and where it's actually a bad thing to have and where it's a good thing to have. So it's more fine tuning flex characteristics of the rear end versus the front triangle, to find that nice balance. You can push out of ruts and be able to be precise while still maintaining good grip levels and good... let's say, make it a bit of a sofa to ride on.

Ross Bell:
And thinking back to your last bike. What were the areas you kind of look to improve on?

Pascal Tinner:
First thing was sizing. I think sizing was a crucial thing we worked on. So during the development of the last iteration or the last bike, we learned quite a few things on how different angles would influence sizing requirements. So this is basically all incorporated in here just with a different manufacturing technology.

Then we also learned a few things about different rear-end systems. So we went away from this kind of virtual pivot point system into a more conventional four bar, just because of how the braking forces interact with your riding characteristics...

And then we wanted also to try a bit more high or mid pivot to have some benefits of rearward axle path and stuff. So there's quite a few things we learned, which we tried to input into this one. But we're never at the end of the road - learning keeps on going.


Ross Bell:
And the gearbox, how are you finding that?

Pascal Tinner:
Yeah, at first I was a bit critical because you have the kind of a grip shift thing, but it's actually not an issue. You just need to plan your shifts a bit more. So if you f*cked up your turn, it's a bit harder to get out of because you can shift under load, but not under full load sometimes depending on which gears you're in. You need to plan a bit more, but otherwise it actually is quite a benefit for your kinematics or your suspension feeling because you have way less unsprung weight.

And there's nothing you can break. This box has been in multiple different prototypes over the last one and a half years. And I didn't do any servicing or anything. I just bent one crank while doing a 50/50, but that's not the gearbox and she's still running sweet.

Ross Bell:
How was it having that weight centered and nice and low?

Pascal Tinner:
I kind of compare it to driving a front engine car to a mid-engine car - your bike kind of feels way more centered. When you, for example, you would start braking, the weight shift is not as heavy, so you can expect less chassis movement basically. So that's one benefit I find. And then it tends to make the bike feel a bit more, how you say, soft and more on the ground. So you maybe consider speeding up rebound speed a little bit on the rear just to get that active feeling back. But in general, it's just having an a tractor basically for rough stuff.

Ross Bell:
Then the construction as well. So I guess we've seen it maybe quite a lot in the last few years, but is it kind of similar to what Pole are doing?

Pascal Tinner:
No, Pole is actually machining two half-shells and then bonding it together, which is actually I think a very, very effective way of doing things. For us it's just the bonding technology we're not on top of right now. So the main advantages for us is we don't have any welds in this. So we kind of can take simulation from the CAD file way more seriously because we don't have to factor in the welds and the welding, which weld goes after which one and all these things, and you don't need an experienced welder to make a beautiful looking frame. So this is basically me coming up with ideas, doing a lot of simulations, spending hours on the computer and then having one made, and then go...

Ross Bell:
Where is it being manufactured?

Pascal Tinner:
It's been manufactured in Germany actually.

Ross Bell:
You guys are Swiss?

Pascal Tinner:
Yeah. We're in Switzerland.

At the moment it's just me because everyone is injured and we do have an under 17 rider, a development rider, Mike Huter, who is doing fabulous at the moment. He just won his first European cup last weekend. And yeah, usually Gamux is a company with three business streams. So we do have distribution in Switzerland, for example, for Manitou, for Ohlins, for Hayes. So multiple brands. So there's a distribution business. Then we do have our frames and our consulting business where we do a lot of stuff in 3D printing, as you've seen before now in machining as well, coming up with our own frames, but also consulting other companies.

And then the third thing and it is really important to us (and that's where the passion is): racing. So yeah, we tend to come back with a bigger team in the future, but it all depends on riders, sponsorship, negotiations, and stuff like this, but for now, yeah, I'm flying the flag kind of with my testing duties. So we have a solid base for Loris and probably some other riders to start racing again next season. It's a bit unfortunate, but injuries happen. And if you have one rider, basically a one rider team in the elites. Yeah. That's the risk. But we knew that when we came into the season, but we tried to make the most out of it.


Ross Bell:
In terms of adjustability, it looks like quite a few of these parts you can interchange quite quickly?

Pascal Tinner:
Yeah. So there's interchangeable upper shock mounts, lower shock mounts. We can even change the bones to create different leverage ratios. And we can change the dropout. This is just a standard setting. This is also why there are CNC machined. In the future they will go to a 3D printed version just because we can produce them much, much quicker. The turnaround, instead of having a month to wait, it's like two weeks; we can change a lot of stuff very quickly.

Ross Bell:
So which things are you going to end up 3D printing you think?

Pascal Tinner:
Probably that piece on the rear shock mount that's in between the bones, probably top shock mount as well, and for short dropouts. I actually already have some, but we need to do some machining on them to make the axle fit and stuff.

Ross Bell:
What's the next step for you guys?

Pascal Tinner:
So we'll be back in Lenzerheide. We'll skip Maribor just because there's no sense in me spending a week traveling everywhere and leaving the business open. So we'll be back in Lenzerheide, probably with the next iteration of that. Just doing a lot more testing. And also it's our home World Cup, so you don't want to let a Swiss people not see what you've been doing. Then we'll see for the season after what we can come up with. There's stuff in the works, but you know, things take time and to put the signature behind it is sometimes a bit more difficult...

Ross Bell:
Has it got a name yet?

Pascal Tinner:
It doesn't have a name yet. It has a technical reference, which is TRP 197, which refers to the rear end travel. But yeah, it will have a name someday, but since the design will probably change quite a bit in the future...

Ross Bell:
That's probably the last thing you'll do.

Pascal Tinner:
Yeah. It's like a cable routing and forward bump stoppers or the place to put the stopper or something.

Ross Bell:
Just those fine details?

Pascal Tinner:
It's just that you don't worry about that. And then at the last, oh f*ck, there's a double crown. So I need to put somewhere to... Oh, cable routing, oh f*ck that!

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Reviews and Tech First Looks DH Bikes Gamux Gamux Prototype