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Bottom Bracket help


skibum72's picture

By skibum72 - Posted on 10 November 2011

I had my chain off the the bike to give it a good clean before the Fling and noticed that the cranks had a lot of friction ( like it was in the lowest gear). I took the BB all apart and cleaned. Once it was back again the issue was still there. Does that mean I need a new BB or could it be another issue?

[Mod. moved to MTB gear]

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Brian's picture

If you don't have the chain on and it is not smooth then the BB needs cleaning/replacing.

Zoom's picture

The cranks aren't squeezing up against the bottom bracket are they? On modern bottom brackets there are usually one or two spacers. Also there is a threaded adjustable threaded bit on one of the cranks that takes up any slack, That might have come loose and wound itself out.

spindog's picture

it sounds like there's some sort of wear or adjustment issue there? If your BB is in good shape and properly adjusted you should only have very slight resistance when turning the cranks. Without the chain you should be able to give the cranks a good shove and they will freewheel for at least 5-10 or more revolutions? Most BB have some kind of preload adjustment which allows you to setup for the minimum amount of friction from the bearings and this will mean almost no slop/play in the BB when you try to move the cranks by pushing and pulling across the BB (try rocking the cranks backand forth along the axis of the BB). The optimum setting is (almost) no play and no friction. It's a bit of trial and error but worth persevering with to get it right.

skibum72's picture

It is a raceface BB i think X - series, and about 9 months old.
The spacers are on the the BB.
If I give it a good push it would do about 2 turns.

Brian's picture

I don't know if you rate check it by how many turns it does after a push. Go by feel and the sound.

seanc's picture

Raceface external BBs are traditionally crap. Mine seized after about 6 months, and there's lots about the problem on the web. That was a few years ago now, and I would have hoped they'd improve the design.

I replaced it with a Shimano which has been much better, but still not as robust as the old style BBs. It's an easy job to replace although you need the right tools.

skibum72's picture

From the comments I'll replace it. . Thanks for everyone help.

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