Why not more belt drives?
- Thread starter DBentz
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A bike frame has to be designed to "split" at some point to allow the belt to thread between the crank and cassette. Remember, a belt cannot be taken apart like a chain. Some newer designs like those from Riese & Muller (pictured above) raise the chain stay above the drive line, which solves the problem.
Edit: duh...no cassette with belts.
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Dewey
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Belt drives don't work with derailleurs.
The cheapest belt drive ebikes would be a Priority Classic single speed or 3-speed, converted with a front wheel hub motor. [Edit: the Ikea Sladda is out of production and has been recalled because the Continental belt breaks]
eVox is a Quebec subsidiary of Miele, a German washing machine company with experience designing belt driven motors, their Dyname drive uses a flywheel and belt on the left side separate from the chain and gears and is considered robust enough to have found application in some bikeshare systems. Court reviewed the City and KAB models.
Gates has a list of pedal bicycles and ebikes that use their belt drive, and earlier this year boasted their technology is used by 500 bicycle manufacturers. If you wanted to convert a belt drive equipped pedal bicycle some might be suitable for front wheel hub motor conversion which would be the simplest way to do it, otherwise I don't know how easy it is to find parts to make a belt drivetrain work with a mid-drive or rear hub motor. Typically a mid-drive replaces the front chainring while rear wheel hub motors accept an IGH chain sprocket, you would need to find belt adapters to work with the motor and rear hub plus the right length belt. A more radical conversion involving cutting the frame on a standard IGH bike has been attempted by some belt drive conversions.
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fredi
Member
You can’t use a detailer with a belt drive so you either go with a hub gear or single speed. My Evelo Galaxy TT has the Gates carbon belt drive and combined with the NuVinci Harmony automatic transmission they provide a smooth and quiet riding experience. It probably helps that the Bafang motor doesn’t have the annoying high pitched wine of the Bosch.
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Thanks for all the great, interesting responses. The explanations are satisfying for custom self built bicycles but seems like manufacturers less dependent on pre-existing components would have more latitude to market internally geared hubs mated with belt drives. I wonder if the advantages of a belt drive just don't delever that dramatic a payoff. Also, I found this interesting answer from Larry Pizzi at:
https://electricbikereview.com/forums/threads/belt-drive.123/ :
"One of the reasons more ebikes don't use belt drives vs. chain drives, is torque sensing systems on many hub motors which is done on the axle or the drop-out. If you use a belt, it needs to be under high tension for this type of torque sensor to function properly which causes the belt to wear our more quickly then a chain. There are bottom bracket torque sensors available but they are comparatively much more expensive.
The best combo for a belt drive bike is a center motor system, like Bosch and an internally geared hub. You will see these as the eBike market continues to expand."
https://electricbikereview.com/forums/threads/belt-drive.123/ :
"One of the reasons more ebikes don't use belt drives vs. chain drives, is torque sensing systems on many hub motors which is done on the axle or the drop-out. If you use a belt, it needs to be under high tension for this type of torque sensor to function properly which causes the belt to wear our more quickly then a chain. There are bottom bracket torque sensors available but they are comparatively much more expensive.
The best combo for a belt drive bike is a center motor system, like Bosch and an internally geared hub. You will see these as the eBike market continues to expand."
emco5
Active Member
Chain is generally more efficient than a belt.
http://www.cyclingnews.com/features/chain-drive-or-belt-drive-whos-faster/
http://www.cyclingnews.com/features/chain-drive-or-belt-drive-whos-faster/
scrambler
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For traditional non electric bicycles, Carbon Belt and Internal Geared Hub do present a small loss of efficiency and extra weight that can be an issue.
But for an electric bike, the assisting power of the motor makes it irrelevant, and the comfort, simplicity, and maintenance gains are well worth it, and a big part of the benefits an electric bike has to offer.
I think there is still a bit of a purist / tradition problem with the industry around derailleur, and for competitive E Mountain Bikes, it may still be relevant, but for the vast majority of E-Bikes, Carbon Belt and Internal Geared Hub are the way to get the full benefit of this type of bike.
Seeing a regular increase of new models providing this kind of configuration, I think people and manufacturers are slowly picking up on that, and the trend will hopefully continue.
The next issue is that, as we will start moving onto more powerful motors than the current 250/350W range, IGH manufacturer will need to address the power limitation of the current IGHs.
NuVinci has recently made a move in that direction with the new N380x that will be launched in September, it would be nice to see the other IGH vendors do the same. But this as usual is a chicken and egg problem, as for them to be motivated, the market first need to move more massively onto these configurations.
Another possible solution would be if new motors would integrate the pedaling gear system, having a non geared drive to the rear wheel (there is no need for gears with a more powerful motor, and would make throttle use easier), but a geared crank for the pedaling assistance.
But for an electric bike, the assisting power of the motor makes it irrelevant, and the comfort, simplicity, and maintenance gains are well worth it, and a big part of the benefits an electric bike has to offer.
I think there is still a bit of a purist / tradition problem with the industry around derailleur, and for competitive E Mountain Bikes, it may still be relevant, but for the vast majority of E-Bikes, Carbon Belt and Internal Geared Hub are the way to get the full benefit of this type of bike.
Seeing a regular increase of new models providing this kind of configuration, I think people and manufacturers are slowly picking up on that, and the trend will hopefully continue.
The next issue is that, as we will start moving onto more powerful motors than the current 250/350W range, IGH manufacturer will need to address the power limitation of the current IGHs.
NuVinci has recently made a move in that direction with the new N380x that will be launched in September, it would be nice to see the other IGH vendors do the same. But this as usual is a chicken and egg problem, as for them to be motivated, the market first need to move more massively onto these configurations.
Another possible solution would be if new motors would integrate the pedaling gear system, having a non geared drive to the rear wheel (there is no need for gears with a more powerful motor, and would make throttle use easier), but a geared crank for the pedaling assistance.
They're coming, I think we'll see more.
https://evnerds.com/tech/ev-motors/continental-conti-48v-mid-motor-48er-revolution/
https://evnerds.com/tech/ev-motors/continental-conti-48v-mid-motor-48er-revolution/
scrambler
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Regarding Gates carbon belt drives, there is also an interesting development.
Normally you only see these on hard tails, because of the belt tensioning issue.
But I noticed Riese & Muller Delite full suspension Model can be configured with a Carbon belt and a tensioning pulley.
https://www.r-m.de/media/filer_publ...bb762827/17_hlf_delite_riemenantrieb_1861.jpg
(Link Removed - No Longer Exists)
So I asked both of them about it.
Riese & Muller said they have had no issue with using the Belt with a tensioner.
Gates, said they were looking into providing an official tensioner solution for their Belt configuration.
So this means that we should be able to take advantage of the Gates Carbon belt even on full suspension bikes
It would also mean we would not absolutely require an horizontal dropout, as we could just use a tensioner for the belt. Still need a Frame that opens up to pass the belt, but there are some DIY methods for that.
Normally you only see these on hard tails, because of the belt tensioning issue.
But I noticed Riese & Muller Delite full suspension Model can be configured with a Carbon belt and a tensioning pulley.
https://www.r-m.de/media/filer_publ...bb762827/17_hlf_delite_riemenantrieb_1861.jpg
(Link Removed - No Longer Exists)
So I asked both of them about it.
Riese & Muller said they have had no issue with using the Belt with a tensioner.
Gates, said they were looking into providing an official tensioner solution for their Belt configuration.
So this means that we should be able to take advantage of the Gates Carbon belt even on full suspension bikes
It would also mean we would not absolutely require an horizontal dropout, as we could just use a tensioner for the belt. Still need a Frame that opens up to pass the belt, but there are some DIY methods for that.
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