Gate Drive Belt

[Jupestar]

Don’t know anything about them, no real interest, other than watching my bosses bike run untouched for nearly 2 years with interest.. he got it serviced 2 weeks ago, and then it gave up today..

Before I cut it off, I’m assuming this is finished? And there is no reason not to cut it off, I hate wasting stuff... but cannot see any further use for it.

[Brucey]

yeah, that is done.

Old belts + a bit of cunning can make half-reasonable strap wrenches

cheers

[Jupestar]

It’s done anyway, I wasn’t involved with the conversation at the bike shop, so I only heard one side. but apparently it ‘happens all the time’. ‘Happened to my mates the other day’.

Not surprisingly they currently cannot get the belt needed. Doubt anyone can.

So it ‘Cannot be fixed, at the moment’. Prepped my me, he did ask if they could get a regular drive chain on it .

After a bit of head scratching, they said ‘probably and it might even be cheaper, can book it in to take a look for you’.

At which point he asked them to cut the belt off so he could walk it home a bit easier.

They serviced it 2 weeks ago, you think if the belt was damaged they should have noticed. Or if it wasn’t damaged, maybe belts do just go and it is that bad luck?

Anyway I reckon a chain, sprocket and chainring would get him on the road. I can’t see that the hub or crank are belt specific. I’ve suggested he try another bike shop.

[Brucey]

chain conversion should be easy enough and should get him back on the road.

Belt failure may have been precipitated by the wrong belt tension being used (either before or after the service) and/or bad alignment. IME belts that are just about to fail don't look much different from normal; they are tricksy little blighters.

cheers

[ElCani]

I like the idea of belt drives (clean, quiet etc) but it seems the reality of tricky set up, sudden failure and seemingly extremely poor availability of (expensive) parts means that they are best avoided. My ‘poor man’s belt drive’ (chain with Hebie chainglider) does the job...

[Jupestar]

Overall I was thinking how well his bike had been doing recently given he doesn’t touch it ever...

But now I remembered the amount of times we have discussed a squeaky BB/EBB and how many times it went into the bike shop (one which is now closed) for a dollop of grease, because of the requirement for chain tensioning post treatment.

(I’ve started to suspect the belt puts additional load on the EBB/BB area)

This is the first time the new shop has done it. I used them to repair a bent RD/Hanger, and they did a good job on that. I do suspect they have got the tension wrong personally, I have some sympathy as they won’t have seen many before, but they definitely could have done more to try and resolve the issue. unfortunately for them as they are newly opened they have developed a reputation for poor puncture repairs as well - not checking the tyre.

demand outstrips supply here anyway, so they’ll be ok, but mobile mechanics were a hot topic in the office today...

[Brucey]

...(I’ve started to suspect the belt puts additional load on the EBB/BB area) ...

it depends how the belt is preloaded. In any event squeaks and creaks (in the BB, chainring mountings etc) are made more likely by the absence of chain lube overspill. A common problem is that the belt drive 'sprocket' on an IGH will work loose on its mountings; again preload doesn't help.

Some belt systems use a relatively low preload and these seem to be less problematic, right up until the belt slips...

Some time ago I converted a friend's bike from Alfine 8s to Alfine 11s. This all went very well but the final stage turned into a nightmare; the bike was belt drive and without a sprocket/drive ring change the hub swap didn't make much sense; the gear range in the A11 hub is mostly increased (vs A8) at the top end, not the bottom end. It turned out that in the Gates belt system that was fitted, it wasn't possible to obtain the parts to achieve the gearing we wanted, even in theory (let alone practice). To this day the bike (sort of gravel with IGH) wears the same gearing as it did before, complete with 'insanely high' ~130" top gear. A change of Gates system would allow a wider choice of gearing (in theory) but the cost of the parts -if you can get them- is simply horrific.

An acid test when looking to buy a belt drive bike is to see if there is any UK stock of the belt drive parts required for your machine. IME there very often isn't any, and Brexit + Covid means that many of the potential supply routes are a bit kyboshed at present.

cheers

[Jupestar]

The online price for the Belt is not that bad. In Germany I found it for €39. The 22-24 week wait on the otherhand....

A possible sprocket I did see on Wiggle for 9.99 didn’t bother to investigate more, as not needed. I was looking for the price of a traditions one.

Anyway for the sake of a belt, I guess the belt sprocket and chainring will be consigned to a desk draw.

I wonder how it will feel with a chain, I do like his bike, I’ve ridden it a few times, but there is a definite spongy feel, which I’ve always wondered if it the belt, or the plasticy crank/OEM pedals...

Guess I’ll find out soon.

[Brucey]

IME the belt will have quite a lot to do with the springy feel. Having said that IGHs with roller clutches in them can feel a bit springy too.

cheers

[mig]

so the only advantage of a belt is lack of maintenance? (until it goes 'pop' in a big way)

it doesn't seem much given the accompanying disadvantages!

[Jupestar]

I was reluctant. as it's not my bike. But really i knew there was not going to be another short term option, So i sorted it out - even another bike shop would have taken a while.

The drive chain on my spare commuter was a suitable match, so it was tranplanted. I was expecting more issues to crop up, but the chainring fitted well. and the belt sprocket needed a bit of gentle prying as it has grabbers, but came off. Chain was too short, but i had a spare anyway.

I'm not to happy about the cheap alloy chainring on the 'plastic' crankset, warned him and suggested he may consider a new crankset to avoid ruining the one on there. but it will get him home. I was going to lend him my spare bike but it as 25mm race tyres on it at the moment, his are more like 45-50mm.

It rode nicely with the chain, felt more normal, so the belt does make the difference to the feel. I wouldn't say one was better than the other, but it did feel slightly more responsive on the chain, smoothness was hard to judge as i've not riden it enough. will be interested to hear how he finds it.

Comparing it to my IGH, i think the big airy slicks and the wider bar improve the ride on the IGH. something i'll consider trying out when/if i get my drive chain back..

[Jupestar]

A possible sprocket I did see on Wiggle for 9.99 didn’t bother to investigate more

Not in anyway suitable. Sprockets way more expensive.

[zenitb]

I had two belts fail in less than a year of use. The first was replaced under warranty .. but the bike was out of action for months while the (excellent and well trusted) bikeshop struggled to get replacement parts. Despite using the Gates app to set the belt tension the second belt failed less than a year later.

I lost patience and put in a basic KMC singlespeed chain, chainring and sprocket setup and have had zero problems ever since.

I was using it for an all year round, 5 days a week, muddy canal commute ... but unsure whether that was a factor in the failure or whether I was doing something else wrong...I am reasonably technical but its beaten me. I am sticking with the chunky KMC singlespeed chain now...something I can service and easily source spares for.

[Brucey]

it only takes a tiny misalignment of the wheel vs the belt run to create extraordinary stresses on the belt; this isn't at all uncommon. Also whilst muck in the belt/tooth interface is quite well tolerated, it obviously isn't good for the belt.

Belt drives are not uncommon on motorcycles and the same issues are present; problems still occur and when they do the parts are not always easily obtained (or fitted; you usually have to remove the swingarm to replace the belt). Belt drives are not commonly used on offroad motorbikes and on-road breakages are often attributed to something like a stone getting flicked up and landing between the belt and the sprocket.

Chains are nothing like perfect by any means, but they are (especially practically speaking) probably "the least worst choice". I expect belts would be a lot better if they were housed inside a case of some kind, but then so are chains too.

cheers

[9494arnold]

That looks like a motor car cam belt to me.
If you have a sympathetic Old school car accessory shop they may be able to help.
(I don't know if they ARE the same , just making an observation. May be that a bike one is more substantial , but a car one does take some stick and they do require periodic replacement )