New article from CNN about Trek’s new chainless bikes
http://edition.cnn.com/2008/TECH/11/19/chainless.bicycles.ap/index.html
It’ll be interesting to see if internal hub gearing systems get more attention now that trek has put some mass production weight behind a drivetrain that requires it.
The reliability and toughness of the system is only so good as the belt cogs and often they are cheap plastic so thats something to consider as well.
The company that makes the belt and cogs uses the same technology as do Harley Davidson motorcycles. It works.
Spot Brand Bikes have been making belt-drive bikes for some time now. Leave it to Trek to throw orange rims on and say they invented it.
It a neat idea and it’s been around for some time though my main concerns are corrosion due to street grim that you can get from riding in the rain, and other corrsosive things.
The secound thing I would like to see is the amount of Torque that these things can handle…
at the bike show last year, marinoni had a track bike with a belt, although i don’t remember much more, so they must of thought that it can pull some torque.
Torque limit is well beyond what you could ever output from your legs. These are just timing belts adapted to cycling use - in theory they are designed to slough off grim and dirt too.
I’m still not sure I trust the the CDS cogs, they look to be made out of plastic, and not one of those fancy ones like PEEK. I don’t care how fancy your coating is, eventually it wears out.
Mike, this Trek move is nothing but a good thing - mass production means everyone wins and the parts will be availlable to actually try one of these out. I can definitely see adding one of these to my surly in 2010, I can’t see my current chainring/cog lasting more than two more seasons anyway.
actually, I’m gonna have to agree with mike on this one. When I was in japan, I saw lots of bikes with internal gears in the hub with belt drive that looked to be easily 10 years old, and definitely “mass produced.” They were not anything fancy, they were just a cheap, efficient way to make a housewife’s bike require less maintenance.
This is not a new idea.
Not a bad idea, either, but nothing revolutionary.
Fair enough. It is also CNN though. If you draw a venn diagram of people who read CNN website stories and people with strong opinions on bicycle drive trains, it would be a strangely shaped diagram.
hahahaha. Goddamn, you made everyone in the library angry with me.
@ ben adler
I don’t doubt that it’s not a new concept and I am sure it was mass produced in the past though the big diffrence is the amount of hype and advertisement that it may have got in the past.
If who ever mass produced in the past was a leading bicycle maker then maybe it would have been diffrent and a lot more people may have been riding them now.
Either way, where ever I look (on any bike blog / forum ) people are talking about it.
Ben, were the bikes in Japan flat belts (looks like a rubber band) or V belts (looks like a smooth V) or timing belts (have teeth)?
belts with teeth.
So motivated by the fact that a timing belt drive system can be bought off the shelf for roughly 100$ I figured I’d try to design myself one of these things.
And I ran into the most obvious problem - there is no easy/effective way to modify and existing bike frame so that you can drive the rear wheel from outside the chainstay and you can’t cut and rejoin a timing belt so you’re stuck modifying a rear drop out to be removable (which while possible on a steel frame isn’t exactly trivial - and no fun on an AL frame since you’d have to re-heat treat the thing).
So toss out belt drives as a retrofit kit or for monocoque composite bikes - I can’t really see frame builders re-inventing their chainstay designs for something of dubious performance value.
you assume that these belts don’t come in “quick-attach” version. In fact, on my farm we use many of these to solve exactly the same problem as that encountered on a bike frame. You snap the ends together, and then proceed to get the strap over your gears as usual (i don’t know about bikes, but on a silo-unloader it’s a real bitch.)
However, even with timing belts, your trouser sleeve remains susceptible to get ripped… What i’ve always wondered is why they don’t make a bike equipped with a drive shaft just like a bus? My cousin molded a carbon drive shaft for one of his classes (for a solar vehicle). For a bike, it could be ¼ in. or less. You put internal gearing hub at the back and voilà.
thoughts, engineers?
Its been done. They even have a bike that is front and rear wheel drive.
The problem is that its a fairly more complicated system - you still have to deal with some sort of internal hub gearing for the rear and its all less mechanically efficient (both in terms of losses and in terms of weight). Its also a lot more expensive.
Hub gearing is also really unsuitable for serious road riding IMO because the demands of climbing vs sprinting are such that no internal hub of reasonable dimensions can keep you a realistic cadence for all that.
So as a product, the only people they are even going to appeal to are the rich urban commuters who ride a bike to work to be edgy.
wow!!!
well Prof. McFee recently had a hub imported from Germany ($1000+++) with 14 gears he says are the equivalent of 53-11, 36-24!! but i forget what he’s got in the front. This for a custom marinoni cyclocross frame. 8)
Has to be, they are the only manufacturers that I know that make anything remotely competitive with a derailleur system. Didn’t realise the 500/14 had such a large ratio range though thats pretty impressive. But man its heavy, and man its expensive - although I suppose its perfect for the sort of people who upgrade to super record, Red or DA Di2 
Although the TT stuff in Di2 is fricken sweet (in that it actually acts functionality and not just jee wiz cool)
John have you seen the animation on this page?
http://www.rohloff.de/en/technical/speedhub/funktional_principle/index.html