Gears for higher powered conversion question

mark_44

Finding my (electric) wheels
Jul 29, 2018
15
2
I've just replaced my rear deralieur on my bafangHD conversion. I' built the bike in 2018 and this is the first time I've changed the gear even with regular use - so its held up well. Cant say the same about chains, or cassettes though.

The long arm SRAM cage had bent in towards the wheel, presumably due to having to deal with more torque than it was rated for. This caused gear changes to be very unprecise, eventually not even being able to get into top with adjustment. I probably could have bent it back, but it got me thinking there must be a more robust setup one can use on mid-drive bikes.

After a bit of searching, I cant say I've found anything particularly appropriate. Is there a more practical solution? Of my 10 gears, I generally make changes of 2-3, even 4 gears. I imagine 3-5 gears in total would be more than enough - and would allow for a more chunky chain?

Any suggestions?

Thanks
 

Scorpio

Esteemed Pedelecer
Apr 13, 2020
362
162
Portugal Algarve (temporary)
Hi, there are some very experienced folk here who will be along to offer advice soon.

My first though is that the derailleur shouldn't be affected by the power of the motor as it's on the untensioned section of the chain.
Is there a chance it was bent when the bike fell over / got some rubbish stuck on the chain / was lent against something that put pressure on the rear?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,461
8,346
61
West Sx RH
Sounds like the derailleur got bent , we have been riding deraileur eapc's & e -bikes for many years with no issues.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
5,163
2,497
Telford
Sounds like the derailleur got bent , we have been riding deraileur eapc's & e -bikes for many years with no issues.
Hi, there are some very experienced folk here who will be along to offer advice soon.

My first though is that the derailleur shouldn't be affected by the power of the motor as it's on the untensioned section of the chain.
Is there a chance it was bent when the bike fell over / got some rubbish stuck on the chain / was lent against something that put pressure on the rear?
It's a BBSHD. With those, it isn't too difficult to bend the derailleur when you try to shift down under power, like when you have to stop suddenly and don't get time to change down before you stop, then you're stuck with trying to pull away in a high gear.
 

chris667

Pedelecer
Apr 7, 2009
164
108
I would suggest that not doing gearchanges while using all that power would be best. Power off, shift, power on.

I'm also surprised, though. As @Nealh said, it's not the side of the drivetrain that is under tension and a bent cage would suggest impact damage.

I suppose the best solution would be a gearbox. But I don't suppose that would help you.

What's a Rohloff hub rated for, power wise? The marketing always used to say "two olympic-class cyclists riding a tandem", didn't it? Quite an expensive thing to buy to experiment with though!
 

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