There is a grinding sound.....

[hypnos]

..... eminating from my bottom bracket area. It is not chain rub. How do I tell if my bottom bracket is heading south? 2003 Campagnolo Chorus bottom bracket with 4700 miles.

[bcm119]

A BB should last alot longer than 5000 miles, but if you suspect it, remove the cranks and twist the spindle in your fingers. It should feel silky, not rough; and there should be zero play. If you don't like changing BB's, get a Phil Wood, it is a wise investment.

[Too Tall]

Take the chain off, rest it on the BB shell. Grab the crank arms at 90/180 and test for slop..there should be none or a tiny tiny amt. is OK. Now, put your ear on the saddle and spin the cranks...what do you hear? If it sounds like antelope trotting through broken glass it's time for service ;)

[Jeff N.]

Just remove and replace the BB. If the sound is gone, it was the BB. If the sound ISN'T gone, you'll know it WASN'T the BB, and you'll have a spare one when it is! :beer: Jeff N.