Belt drive. It may be time to admit defeat.

I’ve had belt drive on my bike for two years now.
I thought I was logging all my rides, but I seem to have missed ten months out, so all I know is that I have done at least 6400km in that time; 2800km with the Rohloff and 3600km single speed.

I’ve broken three belts, then yesterday, I stripped a load of teeth off another one. (Apologies for the faulty camera focus)

I’ve also worn down two front aluminium pulleys. The rear steel ones seem to be lasting OK.

Cycle Monkey is the cheapest source for parts I have found

I use a 50t front pulley, with either a 118t belt and 22t Rohloff rear pulley, or a 122t belt and 28t SS rear sprocket.
The front pulley is about £50 and the belts are £55 or £64, depending on length.
Compare that with around £34 for a Renthal chainring and £11 for a KMC Z610 chain, which I was using before.

I haven’t given up completely yet.
I’ve still got a brand new front pulley, one new of each belt and two part worn of each rear pulley, so I’ll fit them and make an effort to keep track of how long they last.
Then I’ll do the maths and try to work out which is the better option, in purely financial terms.

My guess at the moment is that at less than double the price, a front pulley will outlast two chainrings, so that’s a good deal.
I’m not so sure about a belt at five times the price of a chain.

A Rohloff pully is £63, against £26 for a sprocket.
No price on Cycle Monkey for a rear SS pulley, but I would guess it’s also about £60, against £12 for a SS sprocket.
I never kept proper track of chain and sprocket wear, but would two Rohloff and five SS sprockets last me two years ? I don’t know.

This is new on me, I’ve seen them in shops but never knew they wore out so fast. So what are the good things about belt drive?

Cleaner? No need to lube? Quieter? Lighter? Smoother?

I guess they are made in the same way as timing belts on cars but those are hidden inside a nice sealed cover, so they are always clean and dry.

Its a fair chunk of money compared to SS setup – would have to last a decent amount of time to make it worthwhile

I’ve always thought belt drive was inferior. The motorcycle industry tried it (e.g. on the Kawasaki Z305 – IIRC), and gave up as far as I know. It is very difficult to beat a chain (e.g. in terms of power losses) and buying unusual products is always going to tend to be expensive.

Well that’s disappointing.
According to my records I did that many miles last year on my commuter, I used 2 ali rings, 2 or 3 chains and a WI freewheel (got several hundred more miles out of that gear too before it was retired last week). Pretty badly treated, would have lasted longer if I’d properly cleaned and relubed as needed rather than an occasional quick wipe down with a rag and relube when it got noisy – you know the stuff belt drive isn’t supposed to need.

WI ~£55
chains ~£7 each
Ring was cheap at £18 (got one with the bike)
1 bottle of chain lube ~£5
considerably cheaper per mile.

Was thinking a belt drive system would be perfect for a commuter bike, maybe not.

A revolutionary and groundbreaking new concept you may want to try[/url]

;)

What caused the belt breakages – was it stuff getting trapped under the belt or just during normal use?

I’d blame the rider personally. MTG seems to break EVERYTHING on his bike quickly.

Mtg
Could do with more info as my commuter is belt/alfine and after 11 months still sweet(reckon 2k miles)
Oh and i ordered parts from Germany when i first got bike(upping the gear ratio) and find http://www.carbondrivesystems.com/products/overview/ then Europe good to deal with
What caused the breakages?

Funny that – the belt drive on my and a friends commuters have been running fine for about 4 years now. The only bit that dies for us both on a regular basis is the bottom bracket.

Are you sure you’ve got the belt absolutely parallel with the centreline of the frame, the hub is perfectly square in the dropout and the tension is correct on the belt?

Those are the only things I can think of that could cause you problems.

Didn’t Marc Beaumont cycle round the world using belt drive and only used 2 belts (one of which had to be replaced after about 2000km as it was faulty)?

there’s the conti drive belt.
getting one in for a build in the next few months.

The key is getting the rear triangle as stiff as possible.
anch chain beltline.

https://www.flickr.com/photos/94186938@N04/14002327381/
this is a spare dropout from one we did a few years back.

sorry, here it is.

I don’t think there is an issue when you use them on the road. It’s off road where you pick up mud, grit and stones that’s the issue.

I’m running my belt slacker than advised to see if it reduces bearing wear. Seems to be good so far, doesn’t slip and has the advantage that any crap caught up in it can get out.

a bit like this?

sigh,said it before chain 98.8% efficient…Nothing comes close.

1,100km of sand, sand and more sand with my fatbike/Gates/NuVinci combo. From the tooth wear so far I reckon there’s still a few thousand km left in the front. It’s not too highly stressed though – I’m no Cavendish.

My regular bike has been through a couple of chains, a cassette and 2 chainrings in a similar distance – despite thorough (and time consuming) chain cleaning.

My regular bike has been through a couple of chains, a cassette and 2 chainrings in a similar distance – despite thorough (and time consuming) chain cleaning.

You can’t compare the two – you have to compare it with a single speed or hub geared chain driven drive. My Rohloff with chain needs a new chain and sprocket every 3 years and a chainring every 6. I commute off road all year round and only occasionally wipe the chain over and add more oil.

1,100km of sand, sand and more sand with my fatbike/Gates/NuVinci combo.

Interested to hear more about this – not heard of anyone using a NuVinci hub for MTB.

said it before clean straight chain 98.8% efficient

FTFY

A filthy dirty rusty chain is still more efficient than a snapped belt.

molgrips it’s time to give up on the hope of the belt drive – you’d do better to spend your life waiting for the second coming. I too wanted to be a believer but MTG is Dawkins on a bike – he has lifted the veil from our eyes and now we must find a new holy grail to search for.

cardan drive ftw

we must find a new holy grail to search for

I’m searching for the same grail.. a mud-proof bike.

why won’t somebody build a modern one of these..

it’s not as easy as it looks, especially with modern components.

& weight.

Someone here has the DIY approach, seriously good engineering too belt 2014
and an earlier one here belt 2012

“…I did that many miles last year on my commuter, …”
“…my commuter is belt/alfine and after 11 months still sweet(reckon 2k miles)…”
“…the belt drive on my and a friends commuters have been running fine for about 4 years now. …”
“…1,100km of sand, sand and more sand with my fatbike/Gates/NuVinci combo…”

Yes, but…
What if, as well as all that mileage, you weighed about 95kg and had got on the podium twice for the 12 & 8 hour solo single speed race at Bristol Bike Fest ?
A lot of bike components are made as one size fits all and I think I am pushing things like cranks, pedals and belts beyond their design limits.

This one broke at Catton Park during a 24 hour race.

The mud was atrocious. Everyone was pushing through the woods and stopping to poke the mud out because the wheels wouldn’t go round.
The belt got forced off a few times by all the mud and grass getting wedged under it, until it eventually broke.

There’s an inventor up North who has been building a MTB with a chain case for a while – on full sus, with a special derailleur built into the carbon fibre case. Very clever, scarily complicated ;-)

This is a photo I took at 2500km to show the wear.

This one got a small stone wedged in it.

Which punched right through.

It broke a few weeks later.

Graham please take this in the spirit it’s intended. You do break a huge amount of kit, but you’re not that strong. Yes you’ve had some podium finishes in niche categories at smaller events, but there are a lot of riders far more powerful than you who don’t manage to break anything like the same amount of kit. It’s very odd indeed.

That said, for testing to destruction you seem well qualified, and I guess belt drive has failed.

Everyone was pushing through the woods and stopping to poke the mud out because the wheels wouldn’t go round.

My wheels always stop going round before my chain gives up. I always carry an old tooth brush in he winter as it’s the perfect tool for freeing everything up.

No offence taken, njee20, just as I didn’t intend it as a boast of my abilities.
I’m well aware that Ashton Court for 12 hours is an event that suits my abilities and style of riding and I’ve never got close to matching those results anywhere else.
I had a go on a power meter once, I can’t remember my output, but I was surprised at how weak I am.

There must be something going on though.
Truvativ cranks are pretty high spec, yet I’ve pulled the threaded inserts out three times.
After snapping several Egg Beater pedals, I bought some Ward Industry titanium ones. I snapped one of those in less than a year.
I’ve also wrecked Look and Time pedals pretty soon after fitting them.

One thing that’s come to light since buying a tandem is that I don’t pedal in circles. I very much lunge down on each stroke, then pause at the top and bottom.
Maybe, even though my average power is nothing special, I’m putting higher peak loads on the transmission ?

Quite possible. Power meters average the power through your stroke. It would bea shame to waste all that effort with poor technique eh? :)

I run a cheapo single-speed conversion for commuting, and have done for the last four years. Changed the rings and chain two and half years ago, and other than clean it weekly in the winter, I never touch it. Must have at least 2500km’s on it with plenty life left.
However, I use mudguards which helps keep the worst of the winter crap off, and it almost never rains during my short blasts to work, and the bike is under cover all the time at work. All that stuff must reduce wear as well

My Rohloff with chain needs a new chain and sprocket every 3 years and a chainring every 6

AVDave – how many miles? I think I’ve changed my commuter Rohloff and reversed the sprocket about annually which is probably about 4000 miles on road. It’s stop start/sprinty and I tended to push it so was probably quite tough on it but that chain was stretched beyond what you’d want to run on a conventional geared rig and the sprocket noticably hooked. It’s probably just old discipline – do you just run it all into the ground? Surely the chainring is shot at that point as well?

One thing that’s come to light since buying a tandem is that I don’t pedal in circles. I very much lunge down on each stroke, then pause at the top and bottom.
Maybe, even though my average power is nothing special, I’m putting higher peak loads on the transmission ?

Almost certainly. Sounds like teaching yourself to pedal smoothly could save you a lot of money – smooth power delivery is better for grip as well, might even make you faster.

might try shorter cranks for a while.

95kg though, which is probably heavier than the vast majority of those you might consider more powerful – Cancellara for instance is only 81kg. It’s the weight which has the biggest impact on drivetrain stress, not how “powerful” somebody is, as however weak you might be, the force through the belt/chain is the same for the same rider weight given the same gearing. Graham is certainly using his bike more and in worse conditions than I suspect most heavier riders do.