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Bottom Bracket Wear, when to replace?(7 posts)

Bottom Bracket Wear, when to replace?aggieman
Feb 24, 2002 8:01 PM
I have a Campy Daytona crank and bottom bracket with about 5000 mi. on them. Their is no side play in the bracket and it turns smoothly by hand and light spinning type riding.

When I ride in the 53t (less pronounced in the 39t ring)ring I get a rough feeling coming from the crank bottom bracket or chainring when riding hard, but no noise.

I have checked the crank bolt, chainring bolts, bottom bracket retainers, and chain.

I question whether the this feeling is coming from the bottom bracket bearings and only feel the roughness when higher force is exerted in the pedal stroke, or just some mystical friction feeling coming from the chain and chainring as they contact during rotation???

Any insight is greatly appreciated.

Thanks, Aggieman
re: Bottom Bracket Wear, when to replace?sprockets2
Feb 24, 2002 11:14 PM
you should be able to repeat some aspect of the roughness on the stand. If the bb runs smooth and has no side to side or up and down play under pressure, you may have another drivetrain issue.
re: Bottom Bracket Wear, when to replace?xxl
Feb 25, 2002 7:18 AM
I agree with the other poster; it sounds like perhaps the pedals may be the culprit. Transmitted vibrations from them would be hard to distinguish from the bb, and you've already checked just about everything else. You also mentioned you feel it more under load. I'd check your pedals.
Maybe the chain?McAndrus
Feb 25, 2002 12:01 PM
Others mentioned pedals and I'd certainly check those. I have a bike that originally was 8-speed but in the last year or so I've changed it to 9-speed by changing the levers, rear derailleur, and chain.

I started get a grinding feeling under pressure. I thought it was my BB - the bike is 7 years old - and replaced the BB. The grinding is still there. Everything else checks out so I assume it's the 9-speed chain working agains the 8-speed chainrings. It's my rain bike so I just live with it.
It's the drive trainKerry Irons
Feb 25, 2002 5:50 PM
I'd certainly be looking at the chain/cogs, with the rear hub being a possible culprit. Have you replaced the chain but not the cogs? Have you not replaced either? Is the rear hub properly lubed and adjusted? How does the cassette feel? A BB that turns smoothly with no play is not likely the source of your problem.
Feb 25, 2002 7:56 PM
maybe it's your knees
re: Bottom Bracket Wear, when to replace?JimP
Feb 26, 2002 2:24 PM
I have had similar feelings with my DA setup. The solution was to clean and relube the chain and the jockey wheels on the derailleur.