Anyone done a belt drive conversion?

I’ve been trying to think of upgrades to bikes that would be worthwhile (a subjective things obvs) and reckon that belt drive could be perfect.

I have a 2009 Scott CR1 that’s got a damaged BB so worthless, could be split at the seatstay.

Also a Brompton, the tensioner is one thing (or to allow the fold), I could 3D print the jockey wheel, do I need a snubber? I’m asking on relevant FB groups also.

I haven’t done a conversion but I have two gearbox bikes, one with Gates belt and the other a chain.  The chain is Putolined when I think it needs it which means maintenance is pretty low.  Weighing up the cost of gates belt vs chain there is no way I can claim the belt to be worthwhile.

I am unconvinced about belt drive for two reasons: 1) you cannot alter gearing without a new belt and 2) you have to carry a spare belt at all time

Midland trail quest graham ex of this parish used to wreck them

Only SS or hub gear as well

Because of this on the rohloff shand I have ordered I have gone for chain drive rather than the belt they usually use with rohloff

Ben at Kinetics does belt drive bromptons – dunno how he gets enough tension with the fold but he makes it work

Midland trail quest graham ex of this parish used to wreck them

He wrecked everything he touched, I wouldn’t base my choices on that.

you have to carry a spare belt at all time

I don’t but you could if you wanted to.

I don’t want a walk home if it snaps and for me I was thinking specifically of touring or going right out into the hills

I know what yo mean about MTG tho – and its perhaps more of a theoretical disadvantage than a real one but stuff that cannot be fixed trailside makes me nervous – even a rohlf can turned into a single speed to get yo home

Interesting, thanks guys.

It’s not really about durability (although that needs to be reasonable) or value (within limits) it’s maintenance/dirt.

Yeah the road bike would be single speed which might be limiting, I will experiment with ratios first, it’s just for town and training. but I hear SA made some close ratio IGHs in the past.

The Brommie would be a challenge, Kinetics only do them with a rear triangle and hub upgrade meaning £1.1K, I think I need a tensioner/snubber plus £200 of Gates transmission parts, if they do a belt in a size that would work.

I did several a few years back. I ignored the high tension and set my belts to the same as a chain on my singlespeed, ie not hanging on the bottom run but not taut.

That was the original Gates belt set up, but I believe the new version is better as regards the need for tension.

What you really need for a conversion is a stiff chainstay and a dead straight beltline. If it is slightly off, the belt arrives at the rear cog at a slight angle to the cog, and ends up trying to ride up it. A snubber (not a tensioner) helps in this case. You set it at about 1mm off the belt so it only touches if the belt starts to rise. About 7 o’clock is a good position. The snubber arm needs to be very rigid or it will eventually get bent.

The big thing is having the courage to chop into a perfectly good frame. 🙂

As for breaking a belt, that is no more likely than breaking a chain, probably less so, and a belt is lighter than a decent chaintool – or at least the sort I carry.

Also, there is now a split belt, pricey though. https://www.veercycle.com/products/split-belt-pro?variant=29894666190926

The best frame for conversion I found was the Pompino. It has nice stiff chainstays.

Details here:

Anyone got a Pompino.? Show us your pics.

Cheers Brian, that is brilliant. I saw that split belt kit, it’s pricey as you say.

Quite happy to take a hacksaw to my bikes as you know 😂

My hybrid Cube Editor came fitted with one. Be aware that there are different versions, the CDN line are lower end and the plastic rear cog wears quickly, CDX has a stainless cog. I really like the belt for commuting, my commute is filthy and all I needed to do was brush the belt once a week. But. The stock gearing was huge (Alfine 11) and I wanted smaller gears, the Gates belt and cog are very expensive, so I’ve opted got a chain drive conversion for £35 instead.

I would suggest to anyone interested to first get your hands on a suitable frame for experimenting on before carving up a bike you like.

Also it is possible to beltdrive a bike with no adjustment.

I have done 3 with carefully calculated Magic Ratio. You can make micro adjustments to a dropout by carefully filing one side and then peening the other. The only difficulty is you have to do it to both dropouts and you need to keep them absolutely perfectly in alignment. All that really takes is a bit of care.

I’ll dig up photos of the conversions in the next few days.

I had no idea you were a next level bodger, this is amazing!

Am I being thick? How do you fit a spare belt in the field? I thought you needed to open the rear triangle to fit a belt?

The frame split is normally a bolted joint that you unbolt and spring the two halves apart. Its exactly the same as doing it in a workshop

As for breaking a belt, that is no more likely than breaking a chain, probably less so

Yes but the point is that you carry a quick link so you can fix a chain and carry on.

Belts don’t just snap, you get plenty of warning that they’re going to let go. Chain wear is all but invisible, that’s the fundamental difference.

How many of you carry a spare belt for your car or even inspect it regularly? I know I do neither, it gets a once over when it gets serviced or if there is a funny noise. Had one part failure, caught in time.

I have an Alfine geared commuter bike, I use Putoline on my chain. Maybe 2-3-4 months between applications?

My wife has an Alifine geared commuter bike with Gates belt drive.

I only need one more incident of a toddler grabbing the chain before I get a split in the chain stay to go with a belt drive!!!!! My chain is the mankiest thing in the garage and is at perfect toddler height – I’d love to be shot of it.

n.b. We’ve also gone down the Early Rider belter route for little bikes – cleaner, less rust, faff, safer…

Now to go and read the thread in case anyone else has ctually converted their frame. When I chose a new frame for the commuter I did have to chose between two similar models – one without a split and saved me over £200…

C-A I’ve got a Scott CR1 (SL) with a cracked chain stay, size med. could do a cut and shut?

Bike shop local to me has converted a few belt drives back to chain (g-tech mainly) as gates belt drive spares are insanely expensive

Not a conversion but my pinion hardtail has a gates cdx belt on it.

Only a hundred or so miles in but its been ace so far.

Parts are expensive though, agreed. Rear gates CDX sprocket is £120 or so, belt is about the same.

Still, the belt should last me for years, same for the sprockets so they’re less of a wear and tear item than a chain and sprockets. And if you start to calculate the time spent cleaning a chain and sprockets over the course of a year, there’s a few hours in that…

I had a Gates CDX belt drive.

Main advantages are it’s clean and quiet.

Other than that it’s:
More expensive to replace
Less durable
Can snap (metal bungee hook got tangled in mine)
Needs constant checking for tension or wears out within a week

I changed it back to a chain, as I stopped commuting in my office trousers anyway.

If money is no problem, go for the CDN belt as it is a bit more flexible.
Forgot to mention they are less efficient than chains aswell, maybe 5-10%

molgrips
Yes but the point is that you carry a quick link so you can fix a chain and carry on.

I reckon I could have a replacement belt on in about 2 minutes and be on my way with clean hands.

Couple of other conversions, both Magic Ratio.

I split the frame at the dropout. Turned out to be trouble free.

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This one was a total PITA. Too much lateral flex. Eventually cured it with a snubber, but bent a few before I made one strong enough. It might work ok with the newer CenterTrack belts and cogs.

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I also did a 1930s bike over 20 years ago in Oz, but that was back before digital cameras. It used 8mm belts, but there was too much frame flex for anything but gentle use. I got the necessary parts from Taiwan.

Maybe it’s time to convert another vintage bike to confuse my pedantic vintage friends. Thun in Germany made the parts to take 8mm belts over 20 years ago.

Cheers all – @jkomo mine is already damaged so it’s a good candidate, but I’ll bear that in mind – 56cm?

This is a good video about the gates carbon belt drive and user error when it fails.

Marketing video, that. “Mud is a show stopper” – what? Gimme a break. He says ‘you’d have stopped earlier than that with a derailleur’ ok fine but what about pinion plus chain rather than belt?

And the biggest point of all is that even if you break a chain, you can fix it.

if you can get a ride in a Gates rohloff, do so. i had a days ride on one. i found myself soft peddling because i felt like the belt was gonna snap.

i went for the chain version on my fargo. 3k miles so far. all running good.

Actually, I take back the comment about belt snapping. On mine, the bungee hook fell into the rear sprocket, mashed up that and the belt but this only snapped a week later.

And the biggest point of all is that even if you break a chain, you can fix it.

Whereas with a belt you presumably fling your bike in the nearest skip and buy a new one?

As I said before, belts give plenty of warning that they’re going to snap, chains don’t. If it looks dodgy you replace it, can’t say the same for a chain.

Whereas with a belt you presumably fling your bike in the nearest skip and buy a new one?

Well quick links are tiny, spare belts are not. This is the point. I don’t think I could fit many spare belts in the same box as my tubeless repair kit that slips into my seat pack.

As I said before, belts give plenty of warning that they’re going to snap

The guy in the video touring didn’t appear to get the warning.

I’d almost guarantee the belt would have been showing visible signs of damage prior to failure and I can absolutely guarantee he never inspected it given how he treated it beforehand. He was entirely responsible for the belt failure through repeated incorrect installation.

I’ve seen industrial belts cracked, frayed and even partially stripped that still work, this isn’t the unknown we’re talking about here. This is the exact same type of belt you use for camshaft timing under far greater stresses and longer duty cycles than a cyclist would produce. They are incredibly strong but only if installed correctly.

It’s not even like a belt weighs much anyway.

I do suspect the belt failure issue is more of a worry than a reality. Problem is its binary – its broken or its not.

I have only ever broken a chain once – but I always have spare links and split links with me.

Again for me thinking abouty future proofing and long tours – take a spare belt. Break it and change it – then I have no backup. chains can be bought in any bike shop. Belts cannot

tjagain
….Again for me thinking abouty future proofing and long tours – take a spare belt. Break it and change it – then I have no backup. chains can be bought in any bike shop. Belts cannot

I’m sure your new belt would last the few thousand miles between places where you could buy a new backup… 🙂

Aye – its more theoretical than real but it would nag away in the back of my mind

Thats why I went for chain rather than belt on my new bike

No more of an issue than a mech hanger when you think about it, in most of the western world its not going to be generally hard one to get one shipped to you wherever you are.

But it’s your bike and if you’re not happy with the idea then that’s your choice. It’s not a right or wrong answer.

Haven’t watched that video but have watched a few of Ryan’s tour divide videos, he racks up the miles – hours many thousands of miles did he have on that belt?

And carrying an extra belt on a long trip really isn’t an issue, they coil up like so, to about 10cm across, and weigh barely anything:

I carry a spare quick link all the time for my chain bike but wouldn’t carry a spare belt unless I was on a multi day ride with big miles. Yes, some of that is down to size, a quick link fits anywhere.

Was camping over the weekend with a mate that had a beautiful Travers custom ti fat bike made around Pinion gear box and belt drive, he really was not sold, been a real pain for him with wearing out quickly and belts snapping, he was going for chain conversion back.

All this talk of broken chains, has anyone ever snapped a chain on a singlespeed with a proper chain line?

There are too many questions over belts and not enough advantages, in my view. I’m not going on a world tour but if I ever do I won’t be taking belts. This is one of the alarmingly more frequent instances where I agree with TJ.

chains can be bought in any bike shop. Belts cannot

When I cycled across Africa in 2009 I got a package sent out to me at a future destination and picked it up when I got there. Things have come on since then. You would be able to ship a new belt to you anywhere in the world before your new belt brakes unless you have user error.