t44florida
10 mW
- Joined
- Dec 28, 2011
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Derailler scratching hub motor
- Thread starter t44florida
- Start date
zombiess
10 MW
I've had this problem before and solved it a few different ways.
1st is obvious, don't use low gear aka the big sprocket, this works well if you have multiple front chain rings and have to pedal the bike.
2nd different freewheels have different offsets from the hub motor, at least the 4 I own are all slightly different and are a mix of 1 and 7-8 speed freewheels.
3rd is to do the best you can with adjusting the rear derailleur and then tweak it slightly by hand and then re adjust (this usually works out pretty good as long as not much tweaking is needed).
I was kind biffed at first when I noticed it, but I quickly noticed I never used 7th or 8th on the rear cluster because it was a 32 tooth on most of my freewheels. Just had to get over the mental part of it not working 100% they way I wanted even though I was never going to use it. Then I changed motors/freewheels and the new freewheel was spaced out much further than the previous one and all gears could be adjusted to work.
1st is obvious, don't use low gear aka the big sprocket, this works well if you have multiple front chain rings and have to pedal the bike.
2nd different freewheels have different offsets from the hub motor, at least the 4 I own are all slightly different and are a mix of 1 and 7-8 speed freewheels.
3rd is to do the best you can with adjusting the rear derailleur and then tweak it slightly by hand and then re adjust (this usually works out pretty good as long as not much tweaking is needed).
I was kind biffed at first when I noticed it, but I quickly noticed I never used 7th or 8th on the rear cluster because it was a 32 tooth on most of my freewheels. Just had to get over the mental part of it not working 100% they way I wanted even though I was never going to use it. Then I changed motors/freewheels and the new freewheel was spaced out much further than the previous one and all gears could be adjusted to work.
dogman dan
1 PW
A spacer washer may give you the 1mm you need. Then a combination of a precise adjustment, plus possibly bending the derailur back out slightly may do the trick.
My dirt bike can shift to the biggest gear, but I tend to end up bending back the derailur and getting some rubbing. So I also tend to just not use the last gear. Perhaps for the best, to just set the thing to never go there.
My dirt bike can shift to the biggest gear, but I tend to end up bending back the derailur and getting some rubbing. So I also tend to just not use the last gear. Perhaps for the best, to just set the thing to never go there.
Ypedal
100 TW
on most ebikes you will not need or never use the largest gear on that cluster anyways, with help from the motor you can leave the chain on the smallest sproket and forget shifting lol.. but typical on most kits in that price range.
t44florida
10 mW
- Joined
- Dec 28, 2011
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That's extremely common on these motors. The clearance on that first gear is extremely minimal. You CAN make it work, by bending the derailer or spacing the cluster, but its best to just lock that gear out and don't use it. It's not really needed almost all the time.
Just the price you pay for having a hub in the back.
Just the price you pay for having a hub in the back.
Drunkskunk
100 GW
the right way to set up a freewheel is using a spacer as needed to set the backspace for chain clearance. they come in 1, 2, and 3mm thicknesses and you can stack them for the desired thickness.
the other issue you'll run into is if you use a 7 speed shifter with a 6 speed freewheel, you'll likely have issues since there is extra travel in the derailer for the extra gear. You can adjust the travel of the derailer, lock out 1 gear on the shifter, or replace the shifter with a 6 speed.
It may also be possable to mount a 7 speed freewheel, however you will need to stretch the frame slightly to accomidate. Using 1 of those washers on the outside of the dropout, but placed inside the dropout will likely give you the spacing you need.
the other issue you'll run into is if you use a 7 speed shifter with a 6 speed freewheel, you'll likely have issues since there is extra travel in the derailer for the extra gear. You can adjust the travel of the derailer, lock out 1 gear on the shifter, or replace the shifter with a 6 speed.
It may also be possable to mount a 7 speed freewheel, however you will need to stretch the frame slightly to accomidate. Using 1 of those washers on the outside of the dropout, but placed inside the dropout will likely give you the spacing you need.
t44florida
10 mW
- Joined
- Dec 28, 2011
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John Bozi
100 kW
Mine has scratched too and its a long shimano - I hate it as I never use it - wondering if I should get rid of the 7 speed cluster all together and just chuck in bmx single speed freewheel.
guys around me say keep the 7 for the day something goes wrong and you have to peddle back.
Not sure. have never changed gears.
guys around me say keep the 7 for the day something goes wrong and you have to peddle back.
Not sure. have never changed gears.
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