Thorn Cycles Forum
Technical => General Technical => Topic started by: in4 on February 14, 2026, 04:10:50 AM
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Very interesting and informative article; best read before you get the hacksaw out!
https://thorncycles.co.uk/blog/carbon-gates-belt-drive
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Belt drive from my persepective :
I tend to keep my bikes for quite a long time. The last new bike frame I bought was an old stock Raven Tour step-through frame in 2018. All the bikes I use myself are more than 10 years old, so not worth spending about £400 to try and convert to belt drive. Instead, most of them now have ChainGliders, which prolong transmission life and reduce maintenance, perhaps not to the extent that a belt does.
Two exceptions though :
1 - If I ever replace one of the family Bromptons I would be quite interested in a belt drive. Since retiring I don't use a Brompton on a daily basis, but in bad weather conditions the chain needs cleaning very often - my "record" is just 40 kms between cleaning after 3 short rides in the recent storms. The chain on a Brompton picks up much more road muck in bad conditions.
2 - If I ever get a purpose-built electric bike. But, when the time comes that I need assistance, at the moment my plan is to convert one of my existing bikes, or perhaps a second-hand mountain bike (available for about 50 euros), and use a chain, chainring and sprocket designed specifically for electric bikes together with a ChainGlider. These KMC transmission components cost significantly more than standard ones, but still a lot less than belt drive components.
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Five or six years ago there was another option for belt that did not involve a split frame, the Veer split belt drive. On this forum do a search for Veer belt and you will find a few posts by someone that installed and used one. I have no idea if that is still an option available to buy or not, I have not seen mention of it for some time now. This was the last update on that person that installed one:
https://thorncyclesforum.co.uk/index.php?topic=15262
When I bought my Nomad Mk II 13 years ago, I considered that bike against another bike from a different manufacturer that had the belt drive option. Thus, I considered belt drive. But I decided that I wanted chain drive for one simple reason. When touring where I am carrying heavy loads, I wanted lower gear range than when I am riding that bike near home when the bike would not carry much weight. With the chain drive, I use a 36T chainring for touring, and a 44T chainring for unladen riding elsewhere. This means I add or subtract four chain links when I make the switch. I use a 16T sprocket. Thus my chainring to sprocket ratios vary from 2.25 to 2.75. It is possible that I would have been able with a split frame to buy the sprockets and belts to enable switching gear ranges, but I decided it would be simplest to just use a chain without researching it further. I do not regret my decision at all. Would I make the same decision today? Probably. I have several bikes, all have chains. That said, I used to work as a bike mechanic, doing a bit of maintenance on a regular basis is something that I am happy to perform. Those that want a maintenance free bike, I can understand that too, I know several people that want to do as little maintenance as possible.
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2 - If I ever get a purpose-built electric bike. But, when the time comes that I need assistance, at the moment my plan is to convert one of my existing bikes, or perhaps a second-hand mountain bike (available for about 50 euros), and use a chain, chainring and sprocket designed specifically for electric bikes together with a ChainGlider. These KMC transmission components cost significantly morer than standard ones, but still a lot less than belt drive components.
I agree with you, Martin. Having discovered the Chainglider and the KMC X8 chain, and steel chainrings, I have zero interest in the frame-weakening a belt drive brings with it. It may be that I'm biased by having been a motor racer as a young man, whose specialty was suspensions, which absolutely demand stiff frames. But I'm not convinced by the special electric bike components KMC are marketing.
I discovered steel chainrings serendipitously: I was ready to order a Utopia Kranich but hated the amorphous cranks that was their standard supply, and had been put off the aluminum chainrings that went with the ugly cranks when I used Nexus transmission from Shimano, which ate itself up pretty shortly; I never saw as much as thousand miles from a set. I thought about the Thorn default chainring which then as now had a pretty good reputation of longevity, until I discovered it wouldn't fit in Utopia's Country chain enclosure (same principle as the Hebie's Chainglider but much lighter build). Someone suggested I fit a temporary cheap steel crankset from India, Amar brand, until found a way to buy a set of the Japanese cranks I had my heart set on. It was many months before I found a way of actually having the cranks I wanted delivered to me, from Paris as it happened, and not too long after that a lot of things happened simultaneously: I moved up the steepest hill in town, the Country chain protector started falling apart, I discovered the Chainglider, I bought a not too outrageously expensive electric bike kit to educate myself, and I discovered that the only really satisfactory upmarket chainring inside a Chainglider is Surly's stainless steel model. After about 3500 miles the black paint on the Amar was still intact. When I went from a front-drive to a mid-drive electric motor the Surly chainring couldn't be made to fit, so I got a couple of sizes of 8Fun's standard steel chainrings, dished to fit over their motor to give the right tread width for the Rohloff, both in steel. The chainring that on test I found most suitable has since done 11000 miles inside a Chainglider without any sign of wear. It follows logically that I see zero reason to fit anything more expensive than steel on a utility or touring bike -- I presume a road bike someone intends to race would be built to a more weight-conscious decision pyramid.