New entrant Belt Drive

[flecc]

This new entry belt drive looks different in having a deep tooth profile, rather than the more familiar shallow tooth designs. It remains to be seen whether the friction is worse with this pattern:

Contitech-Benchmark bicycle drive system

 

[jazper53]

I expect the friction would be worse and belts would wear quicker than chains, if there are any advantages, I expect they are for commercial suppliers IMHO

 

[flecc]

I expect the friction would be worse and belts would wear quicker than chains, if there are any advantages I expect they are for commercial suppliers

I fully agree, it wouldn't surprise me to see them change the pattern. Any of these belt drives is bound to be less efficient than a chain and sprockets despite the claims, but the best can be acceptable for some when the benefits are taken into account. They all need separating rear frame sections of course.

 

[johnc461165]

I worked in engineering for 40 years and my experience with toothed belt drives on equipment running in far worse conditions than you get on a bike, is that the lifespan was equal and in some cases better than a chain, I don't have any knowledge regarding frictional losses for chains or belt drive so unable to comment on this.

 

[jazper53]

I worked in engineering for 40 years and my experience with toothed belt drives on equipment running in far worse conditions than you get on a bike, is that the lifespan was equal and in some cases better than a chain, I don't have any knowledge regarding frictional losses for chains or belt drive so unable to comment on this.

Toothed belts do have advantages for applications such as cam-belts etc, where rotational synchronization between two or more components yet to see how that would apply to any advantage in cycling

 

[amigafan2003]

Agreed - the belt life on Gates systems are around around 10k miles compared to 2 to 3k for a chain driven bike in a similar light commuting usage pattern. And if you leave it too long to change the belt, you only have to change the belt, not the chain + whole cassette as well like you do on a chain driven bike.

My next bike for commuting will be belt drive with a front hub motor.

 

[jerrysimon]

Like this

Only problem with belts is you need to get the gear range right first time. Changing sprockets is expensive AND the belt has to be changes as well.

Jerry

 

[flecc]

I worked in engineering for 40 years and my experience with toothed belt drives on equipment running in far worse conditions than you get on a bike, is that the lifespan was equal and in some cases better than a chain, I don't have any knowledge regarding frictional losses for chains or belt drive so unable to comment on this.

I have a similar area of knowledge as you John, and certainly a well aligned toothed belt drive will long outlive a bicycle chain and sprocket drive in cycling conditions. The losses are real though and the efficiency doesn't get near chain's best which can be 99%, to all intents perfect.

For utility-cycling and commuting where ultimate performance isn't high on the agenda but long term zero maintenance is wanted, toothed belt is a very good choice.

 

[OldBob1]

The belts on my old DAf 33 seem to work quite well, and now they are made with Kevlar the life of them has increased 200% as long as they are kept tensioned correctly.
I believe the record is around 150K miles

 

[Old_Dave]

Cars...

Timing belts if not changed at regular intervals = expensive bang
Chain (lubricated) = goes on and on and on and on and on

Moral... look after your decent quality chain as part of routine maintenance and it will last, belts are a cure for a problem that didn't really exist.

 

[amigafan2003]

Cars...

Timing belts if not changed at regular intervals = expensive bang
Chain (lubricated) = goes on and on and on and on and on

Moral... look after your decent quality chain as part of routine maintenance and it will last, belts are a cure for a problem that didn't really exist.

Chains are ok - however most cars suffer from the guides wearing out. Chains are not the answer to maintanence issues.

That's from a 2.9 24v Cosworth engine - same as in my Scorpio. The engine made no noises whilst it was running to indicate there was an issue.

 

[Old_Dave]

But my bike doesn't have guides


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[amigafan2003]

But my bike doesn't have guides


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Yes it does - and a tensioner.

Unless your running single speed ;-)

 

[jazper53]

Yes it does - and a tensioner.

Unless your running single speed ;-)

I assume you are talking about the derailleur(s), which also gives a wider choice in gear selection than the belt could offer, that would be limited to drum or hub gears, which I regard as a major disadvantage IMHO

 

[amigafan2003]

A derallieur makes sense on a mountain bike. On a commuting bike - the 8, 9 or 10 speeds available on a hub drive are perfectly adequate.

For example, my Trek FX 7.5 has 27 gears but I've never been out of the big ring at the front - so I've only been using 9 gears. In fact when I last checked the front mech had siezed due to never being used!

 

[Old_Dave]

Yes it does - and a tensioner.

Unless your running single speed ;-)

Ouch !!

You got meeeee


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[NRG]

8, 9 or 10 speeds on a commuting bike where I live are no where near enough.

 

[GaRRy]

Cars...

Timing belts if not changed at regular intervals = expensive bang
Chain (lubricated) = goes on and on and on and on and on

Moral... look after your decent quality chain as part of routine maintenance and it will last, belts are a cure for a problem that didn't really exist.

Now just tell Ducati that. My ST4 = new timing belts every 12000 miles/2 years (even if only done 1 mile) and really a bad idea to not do so. I think for newer bike they have doubled this but still painfull to get done (and not cheap)

 

[flecc]

8, 9 or 10 speeds on a commuting bike where I live are no where near enough.

Latest Nexus has 11 with 409% gear range, Rohloff 14 with 526% gear range. Surely plenty for an e-bike given the power assist, even if tackling very steep stuff. Common or garden derailleurs only match that Nexus 11 range and very few derailleur setups beat the Rohloff's. I just can't see how an e-bike justifies 24 or 27 gears anywhere, unless someone perversely wants to avoid using the power on hills.

 

[tillson]

Latest Nexus has 11 with 409% gear range, Rohloff 14 with 526% gear range. Surely plenty for an e-bike given the power assist, even if tackling very steep stuff. Common or garden derailleurs only match that Nexus 11 range and very few derailleur setups beat the Rohloff's. I just can't see how an e-bike justifies 24 or 27 gears anywhere, unless someone perversely wants to avoid using the power on hills.

That's my experience too. I find that the power assist gives the gears more flexibility in terms of their speed range. The latest Nexus with its 409% range is great, but on an Ebike, you don't need 11 gears across the ratio range. 5 would be plenty.

The belt drive would probably work satisfactorily on an Ebike with hub gears, but I can't see the point. A chain has always worked satisfactorily, so why do I now need a belt?