chain is huge problem

Discussion in 'Frame Mounted Engines' started by malibu11731, Mar 1, 2010.

  1. malibu11731

    malibu11731 New Member

    I put a grubee g5 on a trek 6500. Its mounted good. At first it wouldnt go more than ten feet then it would throw the chain to the inside of the rear sproket. Then I had it running for a while and now it won;t hold the chain it keeps riding up on the front sproket and falling off the sproket so I have to take the entire cover off and feed it thru with a a spark plug wrench.

    please help

  2. rockvoice

    rockvoice Member

    I had the same problem , switched to 415 chain and solved it.
    some guy's i know have had no problem with the kit chain on the GT5 but i think it fits to tight on the rear sprocket . the other alternative is to try good bmx410 chian from a bike shop, KMC brand is better quality and shouldnt bind
  3. malibu11731

    malibu11731 New Member


    I did what you said, and went to a bmx shop. And got a 410 that is of better quality. I think that the chain that came with the kit was binding at a few links and that was what was making it ride up on the front sproket. I had 2 put two master links in bc the chain was a few inchs 2 short, but the chain i used to extend the chain was from the best cutting I could find from the included chain. When u changed to the 415 did u have to change the sprokets? Thanks for your help.

  4. retromike3

    retromike3 Member

    chain woes

    I had the same problems until I switched to a KMC 415. I would also check your rear sprocket and see if its balanced. It might be that your sprocket is throwing your chain off, mine is bolted on to the rear hub with an adapter and I still see the chain go loose and tight every revolution. Even if its only a little off center it will cause a world of hurt.

    Something else to think about is the cog itself. my original cog was badly plated and I had to file the teeth so that the chain would fit all the way down. That seemed to make a big difference.

    Mike Frye the bike guy:cool2:
  5. AussieSteve

    AussieSteve Active Member

    Besides checking for off-centre, also check the rear sprocket for side-to-side movement.
    You might need to tighten some sprocket bolts and maybe slightly loosen others.
    More than about 5mm side-play can cause the chain to come off.

    I'm changing to #410 chain, but have to grind the sides of my front sprocket slightly for it to fit comfortably.
    #410 is better than #415, if you can get away with it.
    #415 is a little too wide and doesn't fit the sprockets snugly, but without grinding, it's all that will fit mine. (My kit came with 415H chain.)
  6. happycheapskate

    happycheapskate Active Member

    There sure are a lot of threads about the grubee chains.

    Throw away your factory chain and buy the famous Tractor Supply co power equipment roller chain.
    related thread

    If you have a permanently mounted cog (such as the HD dedicated hub), but have tight/loose spots, try marking the cog with a grease pencil, where its tightest, and filing the cog lightly between teeth on those sections, until the chain runs smoothly.