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Belt drives are comparatively expensive and don’t work with derailleur gears. Internal gears, especially cheap systems, still cannot offer as many gears as a de

Belt drives are comparatively expensive and don’t work with derailleur gears. Internal gears, especially cheap systems, still cannot offer as many gears as a derailleur. Belts also need to be pretty tight and thus cannot be used on most bicycles with a rear suspension as the distance between the pedals and the sprocket changes under load. So many people opt against belts.

blacksmith_tb 8y ago
I have seen quite a few belts on internally geared hubs - a quick search turns up quite a few[1] commuters shipping w/ belt + Nexus internal hub. 1: https://www.bikeexchange.com/blog/best-urban-belt-drive-bikes-2018 https://www.bikeexchange.com/blog/best-urban-belt-drive-bike...
- Xylakant 8y ago
  Absolutely: internal gear hubs are the only gears you can use with belts. They just tend to be substantially more expensive for the same amount of gears as a comparative derailleur. Internal gears also tend to have a higher friction than derailleur gears - the really good ones such as a Rohloff speedhub cost > 1000 EUR. Even a comparatively mundane Alfine 11 gear costs ~ 400-500 EUR. A pinion gear isn’t exactly cheap either. In return you get a mostly maintenance free setup. It’s great, but I probably wouldn’t opt for it for a city commuter bike.
cladari 8y ago
There are plenty of motorcycles with belt drive, the suspension doesn't seem to be a problem.
- abakker 8y ago
  motorcycles have different issues. The gear changes are internal inside the transmission, not in the belt drive line. Also, bikes tend to have multi-link suspension with chain growth through the travel. This allows the suspension to be reactive to pedaling forces to reduce rider induced pedal-bob that eats efficiency.
mrob 8y ago
And most belts are a permanently closed loop, unlike chains which can be opened and closed. This means you need an special frame with an openable rear triangle.
- Xylakant 8y ago
  It doesn’t actually need to open, but the frame must be built to support belts. The lower bar of the rear triangle must pass over the belt.
tiew9Vii 8y ago
Interesting comments about the suspension. Several models of motorcycles use belt drive and they have both front/rear suspension. BMW uses them on some of the F models, Buell’s where all belt drive and I think all Harley’s use a belt transmission.

blacksmith_tb 8y ago

I have seen quite a few belts on internally geared hubs - a quick search turns up quite a few[1] commuters shipping w/ belt + Nexus internal hub. 1: https://www.bikeexchange.com/blog/best-urban-belt-drive-bikes-2018 https://www.bikeexchange.com/blog/best-urban-belt-drive-bike...

Xylakant 8y ago
Absolutely: internal gear hubs are the only gears you can use with belts. They just tend to be substantially more expensive for the same amount of gears as a comparative derailleur. Internal gears also tend to have a higher friction than derailleur gears - the really good ones such as a Rohloff speedhub cost > 1000 EUR. Even a comparatively mundane Alfine 11 gear costs ~ 400-500 EUR. A pinion gear isn’t exactly cheap either. In return you get a mostly maintenance free setup. It’s great, but I probably wouldn’t opt for it for a city commuter bike.

cladari 8y ago

There are plenty of motorcycles with belt drive, the suspension doesn't seem to be a problem.

abakker 8y ago
motorcycles have different issues. The gear changes are internal inside the transmission, not in the belt drive line. Also, bikes tend to have multi-link suspension with chain growth through the travel. This allows the suspension to be reactive to pedaling forces to reduce rider induced pedal-bob that eats efficiency.

mrob 8y ago

And most belts are a permanently closed loop, unlike chains which can be opened and closed. This means you need an special frame with an openable rear triangle.

Xylakant 8y ago
It doesn’t actually need to open, but the frame must be built to support belts. The lower bar of the rear triangle must pass over the belt.

tiew9Vii 8y ago

Interesting comments about the suspension. Several models of motorcycles use belt drive and they have both front/rear suspension. BMW uses them on some of the F models, Buell’s where all belt drive and I think all Harley’s use a belt transmission.