fwd-bwd

Schlumpf is showing a new belt drive system at Eurobike 2010. A very ingenious invention I must say. It's a modular system that allows the bike builders and enthusiasts to assemble individualized drivetrains by putting parts together (like LEGO blocks).



According to the company, the benefits of the system include:

- no pretensioning required
- any belt line easy adjustable
- any belt width possible
- designed for industrial standard 14mm pitch belts
- wide range of available belts from 994 to 4410mm length

Read more about it here (PDF link):

https://www.schlumpf.ch/bilder/ABDS.1.engl.pdf

Photos on Flickr (not mine; thank you "bikefix"):

fietsbob

Ah , Why not , larger pitch using Industrial belts rather than re inventing the wheel with a different pitch..

Anyone remember system 10 chains? , were test marked for track, a CM pitch rather than a half inch..

It's just a different kind of chainring, looks like there are several of them stacked up, to get the width ..

From thinner plate aluminum... Overdrive planetary crankset, external gear , 1:1 crank, or 1.6:1..

I'm running the Mountain drive for conventional chain, + a 3 speed, works fine wide range of gears..

one demoed in the PDF looks like a Fixie with a 26" wheel the 40" gear has a 64" high,
or if a 29" wheel, a 44.6" & 71.36" ..

20" wheel? 30.7 & 49.23" not the most useful ..
does suggest dual range on a IG hub..

chucky

But they didn't solve the main problem with belts:
Belt length must be custom manufactured for each bike model and each gear ratio.


All this stuff about improving belt performance and reliability with wider belts and bigger cogs is all fine and good, but unless I can adjust the belt length in order to fit a belt to my bike without relying on imperfect measurements I can't convert my bike to a belt drive nor can anyone else. Measuring drive line length is harder than it looks.

It is interesting what they say about cog wrap and gear ratios, though. If what they say is true belt drives won't work with small wheels due to the high gear ratios. Guess nobody told the makers of Strida.

AEO

how about using nylon stockings?
that's an age old trick for fixing the timing belt to get your alternator working, if for some reason it breaks.

feijai

I thought the main problem was that you had to break the rear triangle to install a belt. Indeed, the pictures shown present an impossible topological paradox.

AEO

just need to look back to the 80's and 90's with raised/elevated chainstays.
actually, I'm trying to find a MTB frame with elevated chainstays.

for almost all of the current production belt drive bikes, there's a slit cut into the dropout, which is held together by a plate and screws.

Chop!

Perhaps it, paradoxically uses a split-link.

Or could Schlumpf be selling his belts with the frame 'pre-installed'

vik 

I've been watching all the belt drive developments with interest. I don't really have any issues with my chain driven bikes so I'm not in any rush, but when something practical and affordable comes out I'd like to give it a shot and see what I think.

As other posters have noted there are a number of issues that will limit the proliferation of belts - at least initially.

JimBeans83

Saw this in person a few days ago at Eurobike,

system is good because not as much tension is necessary with their belt pattern, which means that belt sizes aren't as fixed as you'd think, and you may not have the fragility issues which seem to be scaring many away from belts.

The bike in that photo had a mini S&S coupler through the right chain stay.

brakemeister

yeah it felt loose and sloopy compared to my gates dahon..... I dont know how it works in wet and dirt ... most likely ok ..it seems the gates stuff is lighter and more fragile ( but keeps on trucking in muddy coditions without problems)

thor

AEO

I bet someone would make millions if they came up with a tensioner for a belt drive.

feijai

Okay, so surely this isn't the most solid of approaches.

vik 

It just needs to be as strong as the weld between the seat stay and chainstay...those aren't big tubes so it's not hard to join them with a plate and bolts.

JimBeans83

Thor, what is consensus you've understood for belt drive? Just a marketing gimic for next/past few years, or real application? Howto overcome the fragility aspect, knowing how the belt has been stored, high cost, etc. Opinions I heard limit its effective use to city bikes.

fietsbob

The use of a belt drive in a truck tarp fabric covered 'chaincase' seems Ideal , in the chain case Chains get under lubricated.

Belt drive can be ignored, + in the cover the Belt drive wont attract attention, It's just another bike.

FWIW fastest round the world bike tour was on a belt drive Rohloff Hub Bike.

ChainlessRev

We've noticed quite a bit of movement in the development and integration of belt systems/kits for bikes. The number of after-market belt parts with various sizes and lengths that is available now is very impressive!

Here's Gates on our Abio Verdion:
https://www.abiobikes.com/blog/2010/0...on-belt-drive/