Sturmey-Archer 3 speed Hub gears for crank drive Bafang

[Pete]

Hello all, I have a Halford's Carrera bike that I converted with a Bafang BBS02 crank drive. I am reasonably happy with it except for the gears which I just can't get adjusted right. I have obviously removed the front 3 chain rings but left the rear 8 speed cassette, but they gears are noisy and slip easily and the setup feels quite flimsy and I don't think they are handling the power very well. I only actually need to use 2 or 3 gears for the riding I do and wondered if it would be possible to replace the rear derailleur with an old 3 speed hub gear. A friend has a old bike I can have which has a 3 speed hub on a 26 inch wheel and my question is whether I could swap out my rear wheel and cassette for this wheel and gear hub? You can change gear on these hub gears without pedalling so there would seem to be a lot of advantages if it would work. Am I right in thinking that such a setup, if possible, would be more robust than a derailleur?
I'm sure someone must have thought of this and maybe tried it and it would be useful to have your views.
Many thanks

 

[Nealh]

No reason why not as Shimano hub gears are used as well.

 

[vfr400]

That won't work directly because your frame will have the wrong type of drop-outs to tension the chain, so your're going to need a chain tensioner of some sort. You can do it by leaving the derailleur in place, which will also allow you to keep the same chain. You then have to fix the derailleur in the right position using the high and low adjuster screws or use your present shifter to shift it to the correct position. Move the shifter to the left handlebar to make room for your new three-speed shifter.

Alternatively, you can buy and install a proprietary chain tensioner.

 

[Tarka]

Might just need a new cassette and chain with the gear selection set correctly.
It could be a freewheel rather then a cassette.

 

[vfr400]

Might just need a new cassette and chain with the gear selection set correctly.
It could be a freewheel rather then a cassette.

I think derailleur gears are the much better solution. You have to stop pedalling to shift an SA three-speed. That's not going to work well considering the motors run-on. A gear shift sensor would be essential.

 

[Andy-Mat]

Hello all, I have a Halford's Carrera bike that I converted with a Bafang BBS02 crank drive. I am reasonably happy with it except for the gears which I just can't get adjusted right. I have obviously removed the front 3 chain rings but left the rear 8 speed cassette, but they gears are noisy and slip easily and the setup feels quite flimsy and I don't think they are handling the power very well. I only actually need to use 2 or 3 gears for the riding I do and wondered if it would be possible to replace the rear derailleur with an old 3 speed hub gear. A friend has a old bike I can have which has a 3 speed hub on a 26 inch wheel and my question is whether I could swap out my rear wheel and cassette for this wheel and gear hub? You can change gear on these hub gears without pedalling so there would seem to be a lot of advantages if it would work. Am I right in thinking that such a setup, if possible, would be more robust than a derailleur?
I'm sure someone must have thought of this and maybe tried it and it would be useful to have your views.
Many thanks

If the deraileur is worn, or if just the chain needs replacing, that might explain the problems you are having.
On my first e-bike, after 3 years of fairly heavy usage, I was on my second chain I believe, and was advised to replace the cassette as well, which solved the problems I had had recently had, of the chain "popping off", while underway!
That was a hub bike, with far less wear and tear on those parts....Shimano gears.
As someone else pointed out here (correctly I feel), getting a Sturmey Archer to change gear with motor power, may not be quite as easy as it sounds at first glance.
Furthermore, the extra power from the motor does wear chains and cassettes out faster than say a hub bike, as all power, muscles and motor, are going through that same chain, the so called "single point of failure!" on mid motor e-bikes....
(But do not say it too loudly! )
How quickly a hub gear will wear, I have no idea, but they have some quite thin/tiny (and to my mind "delicate") parts, having taken one apart many years ago.
Whether that is still true today, I cannot say! But I would never give up my 21 Gear, Deraileur gear change, after riding with hub gears many years ago.
IMHO Deraileur are easily adjusted, all the parts are available online for very little money, and its really easy to repair and replace the bits and pieces.
YouTube has great videos of the adjustment procedures.....
But at the end of the day, its your personal choice.
Andy

 

[grldtnr]

I think derailleur gears are the much better solution. You have to stop pedalling to shift an SA three-speed. That's not going to work well considering the motors run-on. A gear shift sensor would be essential.

I think derailleur gears are the much better solution. You have to stop pedalling to shift an SA three-speed. That's not going to work well considering the motors run-on. A gear shift sensor would be essential.

I do wonder?? SA gears are pretty reliable, but you have to consider if they can handle the torque of a motor, SA say you should only use a 2:1 ratio ,i.e. half the teeth on the rear cog of the front ring, per example 21 rear 42 front, some have fiddled with the SA gear by fitting 2 rear cogs,and detailiuer ,I tried it myself, it broke the axle.
They currently make hub gear/cassette hub, I have one fitted to my recumbent trike, one built up in a wheel of your choice can be had for less £200, the hub/ cassette costs about £110, depending on whom you order,
What you asking for is a CS-RSK hub.

 

[Nealh]

Shimano recommend the same ratio 2:1 but many go as low as 1.6:1 without issue.

 

[Antonella]

I do wonder?? SA gears are pretty reliable, but you have to consider if they can handle the torque of a motor, SA say you should only use a 2:1 ratio ,i.e. half the teeth on the rear cog of the front ring, per example 21 rear 42 front, some have fiddled with the SA gear by fitting 2 rear cogs,and detailiuer ,I tried it myself, it broke the axle.
They currently make hub gear/cassette hub, I have one fitted to my recumbent trike, one built up in a wheel of your choice can be had for less £200, the hub/ cassette costs about £110, depending on whom you order,
What you asking for is a CS-RSK hub.

How about a mid motor with a torque sensor like Tongsheng has?