Bottom brackets

The place for discussions on what piece might fit where, where to buy it from, how to fit it, etc.

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Ian Long
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Bottom brackets

Post by Ian Long » Thu Apr 21, 2005 12:35

A topic dear to my heart since my bike is now on its fourth even though the bike is still less than a year old!

From reading forums and talking to various people, it appears as though the life expectancy of a bottom bracket is pretty random and obviously dependent on the conditions you ride in and style of riding etc.

However my first two brackets lasted six months and four months respectively. Six months I could just about cope with, four was disappointing. However the most recent replacement hasn't even managed two months - hence this posting. I may have been unlucky, however my advice is to stay away from a PowerPro 9400 ISIS bottom bracket.

When it was first fitted, there was no play at all in the pedals. Within two weeks I had a similar amount of play to Neroli's bike which is still on its original BB. From then on it deteriorated fairly quickly and for the last couple of rides has been giving alarming metallic clunking noises when I put force on the pedals.

Since I hope to be doing a lot of cycling in Wales next week, I decided it was time to fit BB number 4. This time I have opted for an all singing all dancing one with replaceable bearings, grease points etc. Hopefully it will outlast my time with the bike (a RaceFace Signature FR if you are interested) and pay for itself due to its long life.

Removing the old bottom bracket has revealed the source of the clunking noises. The bearings on the left hand side of the crank are looking unhappy with life. A large portion of them are no longer circular, there are ~12 bearings missing and I dug out the half remains of about 6 bearings from the general grime in the bearing race. :shock: Probably the real cause of the problem was the complete lack of sealing to prevent water and mud getting into the bearings in the first place.

(Despite breaking two frames through metal fatigue, I have never had to replace the bottom bracket on a road bike)
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Al Donald
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Post by Al Donald » Thu Apr 21, 2005 20:28

The cartridge bearings should solve your problems. The external type BB bearings are even stronger, but you would have had to replace the chainset as well!

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Al Donald
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Post by Al Donald » Thu Apr 21, 2005 20:32

This is a shamelessly gratuitous post to move me up to a 'carve gyber'!...

Oh no! I spoke too soon, it did't work! :oops: Must be 150 or 160...hmmm :?

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