Mountain Biking - Belt Driven bikes....

Whats this about these belt drives instead of chains?
I'm reading a magazine that had an article about it.
What do you all think about this? I don't like the thought of belt drives, belts snap and can get all chipped up and can also strip down.

They're about 2-3 times as strong as chains, and last like 7 times longer, these are already used on car secondary drive systems, lawn mowers, helicopters, etc.

I strongly favor the internal hub gearing which is neccesary for this system, Internal hub gear is far superior to cassette type. They never became super popular because older models were trash and had a limited gearing range. But new ones have made enormous improvements over the old internally geared hubs.

I always thought that chains were slightly primitive (yes, i know they have alot of physics and engineering aplied to them) and am amazed at the potential (yet enormous) improvements to gearing through internally geared hubs.

Im fairly optimistic about it.

A belt is also stiffer is it not? That would make it harder to pedal.

A belt is also stiffer is it not? That would make it harder to pedal.

I don't beleive a stiffer belt or chain would make any difference in pedaling efficiency. I may be wrong, but I'd say you'd want a stiffer chain or belt to prevent chain slap from occuring.

I also agree with the fact that belts are superior to chains. The main points have already been made, but they definitelty should last long and seem as if they are easier to maintain. However, not enough research has gone into bicycle belt drives, and theres not much selection, so I'm refraining from buying one.

It seems like the current offerings are perfect from commuters, however.


CMIIW

EDIT- Crap, I'm agreeing with Elf. Now I'm sure I'm wrong. :(

A belt drive system that approaches the efficiency of a chain drive system has get to be discovered.

A belt drive system that approaches the efficiency of a chain drive system has get to be discovered.

Just wondering, do they use chains or belts on most sport (motor)bikes? The guy at my LBS has a chain driven system.

i believe harleys and buells have belts.
with a mtb, though i think that dirt/mud would be a problem.
road bikes maybe?

i believe harleys and buells have belts.
with a mtb, though i think that dirt/mud would be a problem.
road bikes maybe?

It seems like a belt would actually be better off in the mud. You know, know little notches to get clogged, et cetera. If efficiency was truly a problem, than a road bike is better off with a chain.

Just wondering, do they use chains or belts on most sport (motor)bikes? The guy at my LBS has a chain driven system.

When the power available is in the range of hundreds of horsepower, the inefficiency caused is negligible, especially when the tires would break grip from the ground before all the horsepower is used. In a bike, with a human as the 'engine', the circumstances are quite different.

They're about 2-3 times as strong as chains, and last like 7 times longer, these are already used on car secondary drive systems, lawn mowers, helicopters, etc.


Please explain why engine timing chains can usually last the life of the engine, while timing belts need to be replaced regularly, say every 60k miles.

Please explain why engine timing chains can usually last the life of the engine, while timing belts need to be replaced regularly, say every 60k miles.

Obviously the chains are enchanted with LVL4 HARDENING.

It seems like a belt would actually be better off in the mud. You know, know little notches to get clogged, et cetera. If efficiency was truly a problem, than a road bike is better off with a chain.

belt will have notches.

Obviously the chains are enchanted with LVL4 HARDENING.

RIP Gary Gygax

belt will have notches.

I mean, the area in between each link. I know the belt will have notches, but it won't get clogged.

I suppose it would depend on the profile of the belt, but it seems like mud getting between the belt and the pulleys would be a problem, since there's less room for the mud to squish out...?

I read an article in one of the bike mags, Bicycling I think, that said belts and internal hubs are being tested in hybrids and will transfer to road and MTBs if they can assure durability and reduce their weight. I think the derailers days may be numbered.

Personally, it's the way foward. Nicolai also seem to think so and have started using them on their G-boxx bikes.

www.carbondrivesystems.com/ (http://www.carbondrivesystems.com/)

www.nicolai.net/ (http://www.nicolai.net/)

Ah the ole Belt/Internally geared/G-boxx discussion, always a forum favourite for the tech heads.

Personally, i think it's only a matter of time until the major manufacturers start developing and releasing easily accessible, servicable, strong and long lasting internally geared hubs, it is by far the way of the future. The question is not if but when.

Yes, yes, the Rohloff and G-Boxx still exist now, but are uber expensive and not as easy to get parts for as your chips and salt Shimano/SRAM cassette drivetrain.

If I had the money, my DH bike - soon to be replaced - would run Rohloff. But it won't.
I will leave my speel there.

Please explain why engine timing chains can usually last the life of the engine, while timing belts need to be replaced regularly, say every 60k miles.

Its really a completely different matter, engine belts do not drive by using teeth (the ones iv seen anyway) they drive by having a tight contact (friction) with the pulleys on either end, so combined with the flap due to the size of a timing belt (versus the size of a bike belt) more flap is created creating wear on the belt, bike belts work off of teeth, so this problem is negated.

Its really a completely different matter, engine belts do not drive by using teeth (the ones iv seen anyway) they drive by having a tight contact (friction) with the pulleys on either end, so combined with the flap due to the size of a timing belt (versus the size of a bike belt) more flap is created creating wear on the belt, bike belts work off of teeth, so this problem is negated.

Engine timing belts do have teeth, how else would the cams stay in time?

Engine timing belts do have teeth, how else would the cams stay in time?

Maybe im thinking of something else then, im no car mechanic. Either way its been tested on bikes, they last 7x longer.

Please explain why engine timing chains can usually last the life of the engine, while timing belts need to be replaced regularly, say every 60k miles.

Do you know how many bike miles would translate to 60k car miles? I don't know if anyone would live long enough to wear out such a system on their bike. Compare that to the constant maintenance bikes require: chain lube, deraileur adjustment, chain and gear replacements, etc... Bikes are VERY maintenance intensive compared to cars. I routinely go 7500 miles without doing any maintenance on my car, and it probably has 1000x the moving parts count as my bike.

To answer the question, timing chains can last the life of the engine because they live in a very benign environment, sealed away from dirt, dust, and grime.

Do you know how many bike miles would translate to 60k car miles? I don't know if anyone would live long enough to wear out such a system on their bike. Compare that to the constant maintenance bikes require: chain lube, deraileur adjustment, chain and gear replacements, etc... Bikes are VERY maintenance intensive compared to cars. I routinely go 7500 miles without doing any maintenance on my car, and it probably has 1000x the moving parts count as my bike.

To answer the question, timing chains can last the life of the engine because they live in a very benign environment, sealed away from dirt, dust, and grime.

The system wears out more quickly on bicycles because we, as human engines, are much less tolerant of inefficiency in the drive train. It would be nice if there were bike drive systems that were as long lasting as IC vehicles but I don't think any of us would appreciate the piss poor efficiency of ~20-30%.

I know ATV's don't have belt drives.
They stick with chains.

I sincerely hope that the belt-drive/internal hub gearing system replaces the chain/deraileur system, if for any reason that it would make riding in the mud so much less maintenance intensive.

Automotive timing belts operate under high temperature, high speed use. The consequences of failure can be catastrophic. This is an item you'd like to replace before failure.

Motorcycles that use belt drive are generally cruiser types. These bikes have gentler use than high powered sport bikes. The slight give of a belt is a plus on a slow-turning V-twin engine with big power pulses. Helps smooth out the ride. A belt has to be wider than a chain to handle the same load as a chain. This can cause problems with tire clearance on a sportbike. One problem with belt drive occurs when a small pebble gets caught between the belt & pulley. This can destroy a belt in a hurry. Most motorcycles have a guard in place. That's a heavy component right where you don't want it.

Neither automotive or motorcycle applications are comparable to bicycle drive use.

All that being said, I'd like to test ride a belt-drive set up. But there is a reason the chains have been around for over 100 years. Hard to beat for cost & simplicity. A derailluer has a huge span of ratios in a light weight package.

The system wears out more quickly on bicycles because we, as human engines, are much less tolerant of inefficiency in the drive train. It would be nice if there were bike drive systems that were as long lasting as IC vehicles but I don't think any of us would appreciate the piss poor efficiency of ~20-30%.

True, but don't know how that translates to bikes. Remember that the analogue here isn't the timing belt vs. chain, it's the drivetrain. So for a car this would be a torque converter, cog transmission, shaft drive, differential, etc. A bike wouldn't have any of that. I'd think big gains on maintenance interval could be made without resorting to a 20% loss system. A belt/hub gear could be one way to do that.

True, but don't know how that translates to bikes. Remember that the analogue here isn't the timing belt vs. chain, it's the drivetrain. So for a car this would be a torque converter, cog transmission, shaft drive, differential, etc. A bike wouldn't have any of that. I'd think big gains on maintenance interval could be made without resorting to a 20% loss system. A belt/hub gear could be one way to do that.

Yeah, although the rohloff internal gear hub (possibly the best available) has a 3-5% claimed loss compared to a derailleur claimed loss of 2-3%. Efficient as they are there's still room for improvement basically.

The ~20-30% for IC engines is the efficiency making the loss as much as 80% in some cases. Just keep filling the tank :rolleyes:

Yeah, although the rohloff internal gear hub (possibly the best available) has a 3-5% claimed loss compared to a derailleur claimed loss of 2-3%. Efficient as they are there's still room for improvement basically.

The ~20-30% for IC engines is the efficiency making the loss as much as 80% in some cases. Just keep filling the tank :rolleyes:

well even though i dont know anything about engines, the fact still remains that the engine belts vs. bike belt has really no practical relation. I think what it really boils down to is that not enough research and work has been put in internally geared hubs and this is the only real factor (a 1% difference is negligible compared to the gains) that is holding belts from overtaking chains.

Yeah, although the rohloff internal gear hub (possibly the best available) has a 3-5% claimed loss compared to a derailleur claimed loss of 2-3%. Efficient as they are there's still room for improvement basically.

The ~20-30% for IC engines is the efficiency making the loss as much as 80% in some cases. Just keep filling the tank :rolleyes:

I was considering the 20-ish% to be the driveline loss, which I understand as more like 15% but I wasn't splitting hairs. The overall thermal efficiency of about 12% (88% loss) isn't related to cycling since most of that is related to the internal combustion engine, which bikes don't really use. I guess if you look at the net calorie intake for a typical cyclist versus the calories they expend purely on making a bike move then really the car is probably more efficient. :) (Most calories get expended off the bike during normal daily activities).

For road cycling I could see the 1% driveline loss between belt and chain as important, but in mountain biking the big knobbie tires account for more than that difference.

At the last TMBRA race in St Jo, Tx, spot bikes showed up with these incredible belt driven SINGLE SPEED bikes that were very fast, as all of them placed in the top five, including a GIRL in the open single speed race. I don't think they had any milti-speed bikes. The race was hilly, sandy very windy and they had no problems at all with any drivetrains. They also had FREEE BEER , Their tent was very popular. keep riding, whatever ya got and have fun!!

I was considering the 20-ish% to be the driveline loss, which I understand as more like 15% but I wasn't splitting hairs. The overall thermal efficiency of about 12% (88% loss) isn't related to cycling since most of that is related to the internal combustion engine, which bikes don't really use. I guess if you look at the net calorie intake for a typical cyclist versus the calories they expend purely on making a bike move then really the car is probably more efficient. :) (Most calories get expended off the bike during normal daily activities).

For road cycling I could see the 1% driveline loss between belt and chain as important, but in mountain biking the big knobbie tires account for more than that difference.

But we're all running those tires. An equal-strength off-road cyclist with a 1% efficiency edge would (needlessly) beat me every time. In my last race a 1% difference in time was about 14 places.

But we're all running those tires. An equal-strength off-road cyclist with a 1% efficiency edge would (needlessly) beat me every time. In my last race a 1% difference in time was about 14 places.

Well, for racing I'd assume the equipment choice would be different than it would be for your everyday cyclist.