Chainset / BB play?

Stu 74

Checked my bike over a few days ago as I am off for a trip to Scotland on Friday

Found that the chainring on my SLX double needed replacing. Ordered a new one and fitted it this evening. Put the chainset back through the bottom bracket in the usual way.

Took the bike for a short test ride and upon rechecking found that quite a bit of side to side play had developed between the chainset and the bottom bracket (probably about 1mm). Loosened off the pinch bolts, wound in the preload nut thing again (which was now hand loose despite niping it up with a spanner previously) and retightened the pinch bolts.

Took the bike out again for about 30 seconds and again the play was back :?

The non drive side hope bb bearing is feeling very stiff but I can't feel any play in it as such. Could this problem be anything other than the bearing?

There was no play before I replaced the chainring - WTF is going on?

Cheers

Stu

nicklouse

make sure the crank is fully through the BB. it can take a tap. then pre load and then tighten.

Paulkingk

As stated tap the chainset in with a rubber mallet gently and then do the preload nut up i had this exact same problem and this worked for me.

Good luck.

Enjoy Scotland.

Anonymous

And don't use a spanner on the preload bolt. It's only meant to be finger tight - or your BB bearings will die in no time at all.

Stu 74

No I shouldn't have used a spanner to tighten the preload nut! It seems I stripped the thread off it.

It preloaded the crank snug in the right place but obviously couldn't prevent it from slipping outwards once the crank was under load. The only thing preventing the crank from slipping off the shaft, despite the pinch bolts being tight, was that little plastic tab between the pinch bolts.

Replaced with the preload nut off another bike and it is fine now

Thanks for your help guys.

Stu

Anonymous

Far more likely that you damaged the bearings, which gave, and caused the play you noticed.