SOC 14: Effigear Calls in the Cavalerie for new Gear Box Bikes in the US

Seems like a good idea although i’d be interested to know what it weighs compared to a normal crank and cassette. It looks beefy so I would assume more, plus the added weight of oil. I don’t know if the lower unsprung weight outweighs its overall weight

I agree with Gunnstein – why would you want the belt constantly moving? it seems like the weight is there, whether you put it in the rear hub or the gear box – it’s still there, and still unsprung.

http://www.effigear.com/#!weight/c1mow

Mike the weights are listed here in french.

The gearbox wouldn’t be unsprung weight. It’s got a suspension pivot between it and the ground, therefore it’s sprung. secondly, it’s at the center of the bike, at the lowest point, which is the best place for excess weight to reside. However, going to a single pivot, BB-pivot suspension design is DUMB DUMB DUMB. It doesn’t matter how great the drivetrain is if the rear suspension feels like garbage. and it’s all in service of using a belt instead of a chain. use a chain, and you can use an idler and a modern suspension design. There is no way the slight (and debatable) advantages of using a belt over a chain are worth the suspension trade-off.

@paul woodman “the freewheel is built in to the gearbox,so the belt doesn’t always move” Yes it does. The hub is fixed gear, so if the wheel turns, the belt moves. Can lead to serious injury, just ask on a fixie forum.

@smokestack Hmmm, I didn’t consider the fact that the front drive wheel isn’t part of the cranks , you’re correct. However, I’m curious how no chain tension increase due to stay lengthening will affect pedal bob. (I don’t mind some, as an active suspension helps traction during climbs.)

It states that max weight addition over a standard drive train is 1.1 lbs. The weight is non-rotational and at the lowest point on the bike. It has little to no maintenance and a near indestructible belt drive. I agree the bikes presented look a bit cobby. However build one of the high zoot carbon wonder bikes flooding the market these days with a dope suspension lay out (take your pick, KS-link, FSR, VPP, DW-link, whatever) and this thing could be amazing.

@Gunnstein You’re absolutely right, there is danger from the fixed rear hub, (probably more than a normal fixed gear, due to the higher tension of a belt) and you don’t need it for coasting shifts. but it does make sense from a reducing unsprung weight standpoint, and I’m sure they’re counting it as part of the minimal weight gain they’re touting: put a freewheel on there, and it weighs more than 100g claimed weight difference. Belts are lighter than chains, too, so part of their pitch here is that you need to go both belt and fixed gear to make one of these bikes weight competitive with a standard drivetrain. My thought on this is that they should make the drive side chainstay big and boxy, with a detachable cover on each end, and run the drive belt THROUGH the chainstay: that way you’re protected from the fixed gear belt, and the belt is protected from the elements.

If the wheel is moving the shift is that much faster. Plus, your continuously lubing the gears as long as the wheel is moving. Totally a good idea.
The stay isn’t lengthening compared to drive load. That length stays constant. It is only lengthening relative to the center of the bottom bracket/crank arm interface. Since drive load is no longer a part of the suspension equation, a well designed and valved damper unit is all you need to compensate for spinners or squares.

@smokestack There are more inputs to a suspension system than just braking and driving forces, and I’m not quite ready to believe that this system either A: completely ignores either, or B: even if it does, that a well made damper is enough to counter those other inputs. Even trophy trucks and racecars use more than just an A-arm and a damper. Example: it could argued that this design doesn’t have enough rearward axle path to conserve momentum through square edged hits.

@Gunnstein I don’t think that it’s certain that it would be lighter, with advanced aluminum and/or carbon fiber construction techniques. It wouldn’t need that much more mass, and there doesn’t appear to be much ratio between the two belt wheels on this, so they could make them smaller, which would narrow the belt path and how tall the stay would have to be.

why nowadays gearbox bikes have to be like nowadays electric cars – ugly as sh@#$t??

why couldn’t aa enterprising owner rebuild the wheel with a regular single-speed hub (even if still a belt drive – they make em), and remove or somehow disengage the coast feature from the tranny?

@grog – you’re correct, you can’t (at the moment0 run an idler with the belt for 2 reasons. The main one is that the belt cannot be bent backwards, and secondly, it requires constant, fairly-high, tension, so would need some form of constant-force spring applied to the inside of the belt.

Not impossible by any means, but not simple either. For that reason, its easiest to run a single pivot, concentric with the main output shaft. Like a Kona A.
If only someone did a belt-conversion on a Kona A. Oh, I have, and its superb 😉

And I don’t know why you’re all getting het up about the fixed/freewheel issue. Yes, fit a second freewheel to the wheel if you’re worried about tearing chunks out of your leg. Don’t forget you’re talking about a rubber belt, not a steel chain though.

When was the last time you rode a bike like this while wearing long pants and shoes with laces?

I would go nuts over a bike named ” Squirrel “

@groghunter, I kinda dig your internal belt idea, but you would need the beltstay to open up down its entire length, as just on the ends would not be enough for you to get a belt into the frame.

Your axle-through-pivot idea… now that one I can’t shoot down… it’s both overtly excessive and diabolically genius at the same time… sort of like these Cavaleries xD

Also, extremely thoughtful discussion; really glad everyone is being constructive. I love bikes.

Cavalerie says the “gearbox” weighs 2kg and they say their system weighs about 100g more than a standard drive system. I’m sure the unsprung weight saving is a plus and most of the weight low and center makes sense. Also I bet it works well, but there seems to be something wrong with their numbers.

This a quick list of weights and doesn’t take everything into account, but still, 100g? I don’t get it.

Xtr chain 259g, Gates carbon belt 82g, so +177g, xtr rear der 208g, xtr ft der 132g, xtr 11/34 cassette 254g, 1 xtr shifter 103g, 38g for a Raceface 32tooth chain ring = 912g approximate total weight, vs 2000g. And that’s assuming the 2kg “gearbox” includes the full drive train, which I don’t think it does. I think they forgot a zero, at least. I’m sure it is a great system, but you have to keep it real or people will be pissed off. Am I missing something obvious?

Hey Chris in the future you will have to add the weight of oil and a chain/belt guard, even though lets face it…maintenance free, faster/!coasting gearing and bigger clearance, are tickling everybody all over

Putting big torque through small internal gears makes a lot of drag. There’s no way around it.

This is probably OK for local-level DH, but not for riding uphill.

As a designer, I wish gearboxes and planetary systems were more viable. They just aren’t.