BB Spacers

Clockworkali
Clockworkali Posts: 113
edited February 2010 in Workshop
Hi, I have just fitted an Ultegra Sl 53/39 chainset and bb. When the chain is in 39 chain ring and 11 at the back the chain is rubbing on the inside of 53 chain ring. I think the bb needs spacers on the drive side to cure the problem. Anybody any idea where i can get 1mm spacers as it doesnt look like it needs much.

Comments

  • John.T
    John.T Posts: 3,698
    This is quite normal. You should not be using this gear or the 53 with the largest sprocket. The same ratios are available elsewhere in the gears.
    My Fleet.
  • Slow Downcp
    Slow Downcp Posts: 3,041
    Why would you use the 39 x 11? :?
    Carlsberg don't make cycle clothing, but if they did it would probably still not be as good as Assos
  • Clockworkali
    Clockworkali Posts: 113
    I dont think i would, i have come from a triple and its my first time setting up a chainset and f & R mech.
  • andyrr
    andyrr Posts: 1,827
    Assuming that you are running something like 11 - 23 at the back then, without checking, the ratio you achieve with 39 x 11 will equate to 53 x 21 ? Attempting such a big crossover (small front and small back as well as big front - big back) is really not recommended. I might use it for a short stretch when I won't put maximum pressure on the pedals but you are better off going for an alternative cog / chain ring selection.
  • John.T
    John.T Posts: 3,698
    Assuming that you are running something like 11 - 23 at the back then, without checking, the ratio you achieve with 39 x 11 will equate to 53 x 21 ?
    39/11 is 95.7". 53/15 is 95.4". Right where you want to be, in the middle of the cassette.
    andy. You should check before posting then we can get facts not quesswork on here.
    OP. Run your gears through this and see where the overlaps are.
    http://sheldonbrown.com/gears/
    My Fleet.

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