chain roll over / e-bike

jpc6000
jpc6000 Posts: 8
edited January 2018 in MTB workshop & tech
my mtb is equipped with a bafang bbs02 1200w motor
shortening (1000km) I have placed a Shimano Deore XT CS-M770 Cassette 9-speed silver (Execution: 11-34 teeth), in front is a bling ring 52t
from the 3rd smallest rear sprocket the chain starts to run, I already have this from the beginning)
a new shimano e-bike chain has just been placed, problem has only been worsen
when using the second smallest sprocket, the chain jumps constantly, with the smallest gear less, about 1 x per second, more when I put more power on it myself
my speed is then around 40 to 55 km / ph
what is wrong?

Comments

  • cooldad
    cooldad Posts: 32,599
    Can't really understand what you're saying, but probably a bad chain line.

    Or mech not designed for such a big ring.
    I don't do smileys.

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  • fenix
    fenix Posts: 5,437
    Does it do this when pedaling or just under E-power ?
  • jpc6000
    jpc6000 Posts: 8
    Bad chain line? How can I see that?
    With smaller front-sprocket 46T I have the same problem

    under e-power when use more power from mine own, it worsen.
  • The Rookie
    The Rookie Posts: 27,812
    Measure the front chainline, the centreline of the front chainwheel should be either 47.5 or 50mm from the centreline of the bike frame (middle of the seat tube).

    What exactly does 'the chain starts to run' mean, come off, skip teeth or what?
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • veryslowtwitch
    veryslowtwitch Posts: 321
    Hi, this sounds like a very powerful motor. and 55kph is very fast for an mtb on the level.
    So I think you’ve really got a motorbike with motorbike problems and should ask an ebike or electric scooter mechanic.
    Please be careful. 1200w is Mark Cavendish stamping on your pedals and could damage you, your bike or someone else.
  • davee128
    davee128 Posts: 27
    If you've just replaced the chain and it's now skipping on the smaller sprockets, I'd suspect that the cassette is worn, if it didn't skip before the chain was replaced.

    Sounds like an electric motorbike to me! Certainly not legal in the UK as a bicycle...
  • jpc6000
    jpc6000 Posts: 8
    the lockring was loose, in the mean time the motor is stuck.
    So I do not now if I have it still.
    A new motor is underway

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