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  1. #1
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    Hub motor with 6-7 speed freewhell on a bike with 8 speed casette

    Hello,
    I am looking for an e-bike kit to put on a MTB.
    Problem is that all decent MTB's come with at least 3 x 8 speeds drivetrain. Most of the hub motors only allow a 5-7 speed freweel.
    How will this setup work: 8-9 speed index shifters, smaller chain, etc. etc with a 6-7 speed rear wheel ?

    Again, you can not go front, as most have Al suspension fork.

    Really the only solution is a $100 WallMart bike?

    Thanks for your reply.

  2. #2
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    I have a 3X9 on my bike and the BionX hub fits the 9 gears with disk brakes... EDIT; I guess what I am trying to say is I think the make them for 7 or 8 gears too...
    Last edited by 350htrr; 08-16-13 at 02:41 PM.
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  3. #3
    Senior Member spirit733t's Avatar
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    "Hello,
    I am looking for an e-bike kit to put on a MTB.
    Problem is that all decent MTB's come with at least 3 x 8 speeds drivetrain. Most of the hub motors only allow a 5-7 speed freewheel. "

    my bike came with a 10 speed rear cassette, and this is a 1200 pound bike, i bought the 6 freewheel rear hub bmc motor, and surprisingly it works fine, you see the clever part lies in the gear shifter itself, sometimes you will need to shift twice on the shifter to change gear, but 99 percent of time it is quite smooth and I did nt need to change anything..

    the kit I bought was a bmc v4 and it came with a 6 speed freewheel..


    so I think your over complicating things; and you will be surprised how well a 6 speed freewheel works..
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  4. #4
    coprolite fietsbob's Avatar
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    N+1 rather than a Bad conversion, Just buy a built up turn the key and Go E Bike.

  5. #5
    Transportation Cyclist turbo1889's Avatar
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    You can use a 7-speed freewheel on a bike with a shifter designed for use on an 8-speed free-hub. The chain width is the same (both 3/32 width chain) and the spacing is close enough for it to work. You will just not be able to use either the first #1 position or last #8 position on the shifter depending on which way you rig it up and adjust the high and low limit screws on the rear derailer so that even if you try to go into the non-existent gear cog the chain won't move off of the spool of cogs. You can get 8, 9, and even 10 speed freewheels that match up with equivalent free-hubs as well but they are harder to find and quality can be spotty compared to just using a good quality 7-speed freewheel.

    Another option is to pick up a decent quality 7-speed rear Shimano index shifter for that side of the bars and swap out for the 8,9,10 speed shifter to work perfectly with the 7-speed rear freewheel.

    In addition there are already a select few rear hub motors on the market which take a free-hub cassette instead of a freewheel, and I think as time goes on we are going to see more of them available that way. Personally I don't like to use more then 8-speeds on the rear because I don't like the thinner weaker chains and sprockets that are used with the 9 & 10 speed set-ups. I like to stick with standard 3/32" width chain and sprockets for strength reasons.
    Last edited by turbo1889; 08-17-13 at 07:34 AM.

  6. #6
    Senior Member TiBikeGuy's Avatar
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    I have seen e-bike kit that consists of the front wheel hub motor, controller, twist throttle and batteries. That way you don't mess around with the bicycle's gear system. You can have 7, 8. 9 or even 10 speed on the rear using a top shifter or rapid fire shifters for the rear and the twist throttle for the front motor. The kit comes with the motor already laced to rim so setting it up is easy. They supply the motor in various power from 200W to 500W, 24volt to 48 volt, and rims from 16 inch, 20inch, 24inch and 26inch.
    Last edited by TiBikeGuy; 08-17-13 at 05:38 PM.
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  7. #7
    Senior Member chas58's Avatar
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    +1. Very good reply.

    Quote Originally Posted by turbo1889 View Post
    You can use a 7-speed freewheel on a bike with a shifter designed for use on an 8-speed free-hub. The chain width is the same (both 3/32 width chain) and the spacing is close enough for it to work. You will just not be able to use either the first #1 position or last #8 position on the shifter depending on which way you rig it up and adjust the high and low limit screws on the rear derailer so that even if you try to go into the non-existent gear cog the chain won't move off of the spool of cogs. You can get 8, 9, and even 10 speed freewheels that match up with equivalent free-hubs as well but they are harder to find and quality can be spotty compared to just using a good quality 7-speed freewheel.

    Another option is to pick up a decent quality 7-speed rear Shimano index shifter for that side of the bars and swap out for the 8,9,10 speed shifter to work perfectly with the 7-speed rear freewheel.

    In addition there are already a select few rear hub motors on the market which take a free-hub cassette instead of a freewheel, and I think as time goes on we are going to see more of them available that way. Personally I don't like to use more then 8-speeds on the rear because I don't like the thinner weaker chains and sprockets that are used with the 9 & 10 speed set-ups. I like to stick with standard 3/32" width chain and sprockets for strength reasons.

  8. #8
    xtrajack xtrajack's Avatar
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    Quote Originally Posted by TiBikeGuy View Post
    I have seen e-bike kit that consists of the front wheel hub motor, controller, twist throttle and batteries. That way you don't mess around with the bicycle's gear system. You can have 7, 8. 9 or even 10 speed on the rear using a top shifter or rapid fire shifters for the rear and the twist throttle for the front motor. The kit comes with the motor already laced to rim so setting it up is easy. They supply the motor in various power from 200W to 500W, 24volt to 48 volt, and rims from 16 inch, 20inch, 24inch and 26inch.
    That is what I did. I was thinking that sometime in the future I would like to try a Nuvinci rear hub. I did have to replace the aluminum shock fork with a steel solid fork.
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  9. #9
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    I have a cheap Schwinn MB that I'm planning on putting a front hub motor on. It is steel, at least the dropouts are. I think with a fairly low power motor (probably a QT100) and torque arms, it should work fine. I didn't want to mess with the gearing so I figure the front hub is just easier to deal with. I guess the shocks are also steel but I'll check. I read somewhere that I don't really need to worry about the shock. I certainly hope that's true.

  10. #10
    Senior Member chas58's Avatar
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    pretty much all front shocks are alloy dropouts and not compatible with a front hub motor because they are not steel.

  11. #11
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    Quote Originally Posted by chas58 View Post
    pretty much all front shocks are alloy dropouts and not compatible with a front hub motor because they are not steel.
    Does a magnet stick to an alloy dropout? I checked that. Maybe they do though if there is enough steel in the alloy?

  12. #12
    Senior Member chas58's Avatar
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    If the magnet sticks to it (the bottom part where the hub attaches), then you should be OK. There are a few shocks out there (entry level) that are pressed steel. The most critical piece is the dropouts, as that is what usually fails (breaks) for alloy forks. Steel will bend alot before it actually breaks. But obviously anything breaking in a front fork is going to cause you to hit the ground hard when you are riding as speed.

    Steel fork, torque arms, low power motor (350Watt and 17 amp or less) is relatively safe.

  13. #13
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    Ok, I ordered a front kit with a Q100. Should be fun putting it together. Thanks for all your help. Hmm. And the help to come.

  14. #14
    Senior Member chas58's Avatar
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    check the wiring matches the throttle to the controller, and buy a spoke wrench and keep an eye on the spoke tension for the first couple hundred miles if you got a Chinese wheel. Just sayin...

  15. #15
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    Quote Originally Posted by chas58 View Post
    check the wiring matches the throttle to the controller, and buy a spoke wrench and keep an eye on the spoke tension for the first couple hundred miles if you got a Chinese wheel. Just sayin...
    I'm sure it's a Chinese wheel. But front so no dish to worry about. I've learned with the Trek to check the tension whenever I wait for the freight elevator. One just broke last week - I carry a few spares. Spokes are light. It had been a while since I broke one.

    I'm sure the wiring won't match.

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