freewheel spacing/shifter questions

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tolkaNo   1 W

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freewheel spacing/shifter questions

Post by tolkaNo » Apr 17 2018 2:16am

Im still in the process of building my ebike and when i mount my wheel on my bike the chain rubs against the dropout when im on the 11t sprocket

Im using the 7 speed freewheel that came with the bike which is slightly too wide

I can shift all the way up and down the sprockets fine on my 9 speed sram x7 shifter and derailleur also

In the future i plan on upgrading to a sram x0 9 speed twist shifter and putting it on the left side of my bars upside down so i can shift with my left hand and throttle with right hand because i like that design

So i have a few problems obviously

The 7 speed freewheel is already too wide for my dropouts and is rubbing, and the 9 speed shifter isnt ideal because it shifts approx 2.5mm at a time and the 7 speed freewheel has about 3mm-3.5mm spacing between sprockets, though it does work its probably not as precise as it should be

Im wondering would the best solution be to buy a 6 speed freewheel which will have less overall width and also buy a 9 speed freewheel which has the correct spacing between sprockets and just put the 9 speed sprockets on the 6 speed freewheel and then put that on the bike?

Obviously i would only be able to fit 6 possibly 7 of the sprockets on but it would give me the correct spacing and good shifting as well as allowing me to use a quality shifter

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MadRhino   100 GW

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Re: freewheel spacing/shifter questions

Post by MadRhino » Apr 17 2018 3:53am

You could just fit a washer on the axle shoulder to spread the dropout a little. The chain won’t rub anymore and you can ride with your actual freewheel. The washer can be filed to axle shape from a 10mm washer, or you can use a C washer.

Or, You could use a 5 spd freewheel, for 5 speed is enough with an ebike. Then you’d have plenty of clearance.
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tolkaNo   1 W

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Re: freewheel spacing/shifter questions

Post by tolkaNo » Apr 17 2018 3:59am

MadRhino wrote:
Apr 17 2018 3:53am
You could just fit a washer on the axle shoulder to spread the dropout a little. The chain won’t rub anymore and you can ride with your actual freewheel. The washer can be filed to axle shape from a 10mm washer, or you can use a C washer.
Good call on the washer that might work, but id still be using a 7 speed freewheel on a 9 speed shifter with sloppy shifting
MadRhino wrote:
Apr 17 2018 3:53am
Or, You could use a 5 spd freewheel, for 5 speed is enough with an ebike. Then you’d have plenty of clearance.
6 speed would fit too, but my point was kind of if i use a 6 speed twist shifter i end up using a very old crappy plastic shifter like an sram mrx

I dont think you can find any good quality twist shifters until the 9 speed range like an sram x0

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motomech   1 GW

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Re: freewheel spacing/shifter questions

Post by motomech » Apr 17 2018 7:14am

The washer deffinately works. I use a flat washer straight from the hardware.
You may have to spread the chain stays slightly to fit everything in, but it's no big deal, I can do it by hand or sometimes a little careful prying w/ a flat bladed screwdriver.
I use a 7-speed free wheel w/ a 9-speed chain and derailleur and it shifts fine, but I only use 1 or 2 gears, maybe 3 at the most and if you have any kind of hub motor, you won't shift it any more than that either. Even on my "assist bike" w/ it tiny Q100 hub motor, I only use 2 or 3 gears. So I just adjust the derailleur to optimize the shifting on the lower three gears.
Speaking of adjusting the derailleur, I assume you are using the DNP free wheel because it's the only one w/ an 11 T sm. gear. I have found that because of the shape of the teeth(shark fin shape), shifting can be improved by moving the derailleur up higher and further forward than it's normal position.
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dogman dan   100 GW

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Re: freewheel spacing/shifter questions

Post by dogman dan » Apr 18 2018 8:23am

Yes, you need some more spacer washer. This may mean the dropout needs to be wider than 135 mm, with that spacer in place.

It's ok to flex out an aluminum frame 4 mm or so, 2 mm per side, so you have that much wiggle room.

Then replace your shifter to 7 speed, or friction shifter. Its possible your 9 speed chain might fit bad, requiring replacing chain and both derailleurs with 7 speed type. hopefully not. if this does happen, replace the whole bike with a 7 speed bike would be easier.

tolkaNo   1 W

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Re: freewheel spacing/shifter questions

Post by tolkaNo » Apr 19 2018 6:39am

Short term ill use the washer, long term ill go with the original plan to put thinner 9 speed cogs onto the 7 speed freewheel so i can use a quality shifter and possibly also squeeze 8 gears onto it :shock:

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dogman dan   100 GW

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Re: freewheel spacing/shifter questions

Post by dogman dan » Apr 21 2018 1:26pm

ok, but you'll only use the highest gear anyway.

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