General Discussion Triathlon Talk » Bottom Bracket Woes Rss Feed  
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2004-08-03 8:04 PM

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Master
2447
200010010010010025
Marietta, Ga
Subject: Bottom Bracket Woes
I was out riding today and noticed something about my bike. When under real heavy load, I was hearing a slight grinding that seemed to be coming out of the bottom bracket. I pulled the rear wheel and put another on to make sure it wasn't the wheel/cassette/deraileur setup and it still made the grinding noise. The crank is Shimano DuraAce and has less that 300 miles on it. Its going to the bike shop tomorrow, but does anyone know why this would be happening?

Thanks.


2004-08-03 9:08 PM
in reply to: #43287

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Elite
3235
2000100010010025
San Diego
Subject: RE: Bottom Bracket Woes
No, But will you let us know what it was? It started happening to me as well.
Thanks
Tom
2004-08-03 9:29 PM
in reply to: #43287

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Veteran
230
10010025
Sydney
Subject: RE: Bottom Bracket Woes
aluminium frame? They echo the tiniest of problems heaps and can make it sound like the bike will spontaniously blow up at any moment. it can get you pretty paranoid sometimes. cranks often "click" under load alot too. Its possibly just a bit of dirt in the BB that is trying to stand up and make its voice heard with the echo of your frame. an overhaul, re-lube and tighten should fix the problem.

.::aidan::.

Edited by Pro_rider 2004-08-03 9:31 PM
2004-08-03 9:42 PM
in reply to: #43287

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Master
2447
200010010010010025
Marietta, Ga
Subject: RE: Bottom Bracket Woes
I found this on the web at the following address: http://www.spectrum-cycles.com/64.htm

Bottom Brackets
The Chorus and Record bottom brackets are effectively the same units with some material differences.? Two bearings on the drive side and one on the left.? Traditional four sided taper spindles.? Shimano's Dura-Ace bottom bracket is lighter and stiffer than either Campy BB or the Ultegra bottom bracket, but it does have a tendency to wear out faster than almost any other on the market. The reasons for this annoying problem are seals that don?t work very well and needle bearings that begin to dig into the spindle surface during hard riding.? Most strong riders can not expect to get more than about 5,000 miles from a Dura-Ace bottom bracket.? The easy fix is to use the Ultegra bottom bracket with Dura-Ace cranks.? NOTE OF CAUTION? - If your bottom bracket threads are not perfectly aligned with each other, you will have immediate bearing problems with the Dura-Ace bottom bracket which can not be solved without replacing the bottom bracket shell. It is NOT the fault of the bottom bracket, but the bearing design requires perfect bottom bracket shells. Older designs were more forgiving of alignment problems. The Dura-Ace 10 bottom bracket is completely different from the others on the market. The oversized spindle is a permanent part of the right crank arm. The two bearings reside outboard of the BB shell like the old Magic bottom brackets did. Bearing adjustment is accomplished by tightening the left crank arm's center cap with a small supplied tool. Very simple.

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General Discussion Triathlon Talk » Bottom Bracket Woes Rss Feed