Fitting a 9 speed freewheel

[StuartsProjects]

I was prompted by the recent update on the post about stretching the rear droupouts to ask a question.

I have Bafang 250W rear hub motor with 7 speed freewheel fitted to a titanium mountain bike frame.

I have been trying out the current 7 speed gears with a real cheap (£10) pair of twist shifters which I find a fair bit easier to use than the standard triggers due to joint pain in my thumbs. The cheap shifters were just a trial and for long time use a better pair are needed.

At this point I am considering the possibility of changing the current 7 speed freewheel to a 9 speed one, Sunrace do a 11-32. Shifting (?) to a 9 speed setup would also allow me to use if needed the original rear (non-motor) wheel sets which are fitted with 9 speed cassettes. SRAM do Shimano compatible 3\9 speed twist shifters.

However the room in the dropouts would need to increase by around 5mm to accomadate a 9 speed freewheel and spacers will be needed on the axle. The droputs will spring apart by 5mm.

So does this sound possible, i.e. fitting a 9 speed Sunrace freewheel in place of the current 7 speed ?

 

[Nealh]

You would likely also need a new rear mech but otherwise shouldn't be an issue as you already mentioned the D/O's will need spreading to take the extra stack height of the freewheel.

 

[StuartsProjects]

You would likely also need a new rear mech

The rear mech is the original Shimano Deore XT from when the bike was a 9 speed non-electric setup back in 2002. It copes OK with a 7 speed freewheel, so I was guessing it will cope with a 9 speed freewheel too.

One thing I am not sure of availability is spacers for the current 12mm motor axle, how much would be needed is difficult to say exactly.

 

[Nealh]

Yes XT will work.

 

[vfr400]

You need to add spacers on the other side of the axke if you fit wider gears, otherwise the wheel will be off-centre, Is that what, you're saying? When you add spacers to the left side, the disc won't line up with the caliper if you have disc brakes, so you have to add spacers to either the disc or the caliper.

I can't see why you'd want all that hassle. What are you trying to solve? You won't be able to swap out the motor wheel for your non-motor one because the gear alignment will be out, so you'd have to reset it all each time. For the sake of a 3kg weight saving, I can't see that it's worth the hassle and expense.

 

[StuartsProjects]

Accommodating the differences for the disk calipers between motor and non-motor wheels is easy. I have the correct spacers for the non-motor wheel in a bag, it takes less than 2 minutes to swap them around for the different wheels. Dealing with the likley change in allignment of the rear gear between motor and non-motor wheels does not take long either.

I plan at some point in the near future to buy a 'spare' rear motor wheel. This would allow me to keep the eBike on the road without needing to wait for parts to arrive to fix a broken motor, possibly taking weeks from the far East.

Same logic for wanting to be able to swap to non-Motor wheels; with a bit of thought and advance planning its short work to switch across to my slick road wheels or knobbly off road set.

The question was really about has anyone tried to use a 9 speed freeewheel on a standard hub motor wheel before, it appears not, and rather than spend the £40 on a 9 speed freewheel and find it does not fit, I thought it worth an ask.

 

[Asinrutee]

You need to add spacers on the other side of the axke if you fit wider gears, otherwise the wheel will be off-centre, Is that what, you're saying? When you add spacers to the left side, the disc won't line up with the caliper if you have disc brakes, so you have to add spacers to either the disc or the caliper.

I can't see why you'd want all that hassle. What are you trying to solve? You won't be able to swap out the motor wheel for your non-motor one because the gear alignment will be out, so you'd have to reset it all each time. For the sake of a 3kg weight saving, I can't see that it's worth the hassle and expense.

You will probably need to change the chain as well, different chain width on a 9 speed