Mechanical efficiency of chain drive vs roller drive


Active Member
Aug 6, 2009
I think it looks cool, I like it!
I got a laugh from the use of a porch light for the headlight. It's a good idea!
Dec 18, 2011
I dont know anything about the math or physics but I JUST change from a roller drive to chain drive today and kept the same HOnda GX35. The chain drive runs much quieter and has better acceleration and climbs much better while keeping a similar top speed. Just by looking at it run I would guess there is much less friction loss involved in chain drive......guess that's why a friction drive is called friction drive:)


May 14, 2016
A chain drive would be more efficient than a friction drive, owing to tire deflection caused by the loading of the drive roller. As to the 30% figure, I feel this is an inflated number based on personal experiences with both drive systems. The biggest drawback to the friction drive is wet roads, which causes the roller to slip. On the other hand they are less expensive, much lighter and much quieter than chain drives.

I'm currently building another friction drive for my wife, she wants no part of a chain.
FD's are alot cooler too. A shifter would do wonders for it.


rawly old

Feb 27, 2011
FD's are cool 'til it gets wet, which is much of the time here in the Pacific NW. For me, a belt drive over chain or FD. Even
a GEBE kit has a drawback, which is the stock cog being too small for my Tanakas' power & acceleration.....But by adding
a larger one the belt is less inclined to slip. This increases top speed, but that not why I've done it. It cruises at 14 mph at
3200 rpm,(scarcely more the idle), using very little fuel. On the flat,(theoretically) it would get well over 200 mpg with
pedal assist. (nothing's that flat here.) The Tanakas are so dependable. I ran for near an hour at 14 mph, the engine was
still almost cool to the touch. To bad, you can't buy a PF 4210 any more, 7 year warranty for private use. Takes a 1000 mi.
just to break one in. They stopped making them; that much quality just wasn't cost effective .


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Active Member
Mar 19, 2018
friction sucks spend more on tires and limited gear ratios
the only way to calculate this is too have a chain drive and a friction drive side by side. Since Work = force * distance, hang a 1kg weight on one end of the wheel and see if it can balance 0.9kg weight on the other wheel, assuming the diameters or distance of each wheel is the same. If they werent you would divide or multiply by the gear ratio. So lets say for the chain drive it is 90% efficient because if it was 100% efficient it would balance a 1kg weight. If the gear reduction was 3x, it would have to balance a 3kg weight.... see where i am going. Do the same for the belt drive and lets say the 1kg weight was balanced by a .7kg, now that would mean 70% efficient as the extra work was converted into friction. These are made up numbers, but yeah if anyone wants to do this try it out and post the numbers. The greater the weight, the more accurate.


Well-Known Member
Dec 13, 2015
I have a motorize bike aquaintance in town he had trouble with the chain breaking he went to a place called 718 Motorize Sports bought a not 415 but a 420 chain looks motorcycle tuff and it fits the gears much snugger than any my 415 chains much wider yet still fits no tension wheel needed on his, damn I wish I would of known that I would of bought one too. Don't know if they knew a metric from standard another chain-gang operator said they won't inter-chain!