Singlespeed & Fixed Gear - Squeaking BB
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05-09-05, 11:49 AM
The Bottom Bracket on my three month old Pista has developed an occasional squeak in a portion of the spin.
I ride in a lot of wet and crud, and given the bargain basement price of a Pista, it would not surprise me if the BB started to fail early; although, some people on this forum have reported several years service out of their Pista's BB.
Assuming a failing BB, when the time comes to fix it, do I just change the cartidge bearings or do I get a whole new, higher quality BB?
I have an excellent chain line right now, and I don't want to do anything that would cost me that good chain line.
If I replaced my present BB with an upgrade, which BB, dimensionally, would give me the same interface with my crank and thus preserve my chainline?
If I can accomplish the same thing by replacing the bearing cartridges with something better, why not do that instead?
Have I sufficiently revealed my ignorance?
05-09-05, 12:08 PM
hey ken, you could just have a loose BB cup. i'm assuming the pistas have a shimano type cartridge BB, so all you have to do is remove the crank arm and tighten the cup down, its a pretty easy fix. try the non-drive side first, because in my experience thats the one that'll loosen first. oftentimes, its a good idea to check the tightness after a couple of hundred miles, especially given that its a new bike and it'll take that long for things to settle into place. also, the cups should be tightened to around 300 to 360 inch pounds. as far as replacing the BB, it seems crazy you would have to at this point. but, assuming what i have about the pista's BB, you should be able to use a shimano un 52 or 72 with the same spindle length and it'll last for a long time. or you could go really crazy and get a phil wood or something that'll last even longer and give you the option of dialing in chainline a few mm or so.
05-09-05, 01:51 PM
Check your chainring bolts too... last weekend my BB (or so I thought) was squeaking and I was freaking out. Turns out loose chainring bolts were my problem.
05-09-05, 02:04 PM
Yeah replacing the BB should be your last of several options. Chain ring bolts, lube the chain, check the lube on the pedal threads, check the tightness of the actual crankarms, then check the BB cups...
How OLD is your BB?
on the '05 pista, the sugino rd cranks sit very very close to the cups due to the short 103mm bottom bracket. this means that a ton of crap will invariably get caught between the cups and the crank arms which, for me, has caused a lot of weird grinding and other nastiness that has nothing to do with any part failure. of course, i've never had any creaking. generally, my assumption with front drive-train creaking is that your crank (or, possibly, chainring) bolts are slightly lose. i'd say that you should take off the cranks, clean out the cups, and, as suggested, make sure that they are tight -- drive side is left threaded). before putting your cranks back on, i would advise (re)greasing the tapers and then making sure that the crank bolts are nice and tight when you put the cranks back on. a word of warning -- don't go too tight on the bolts... i just broke off a bolt in my bottom bracket from cranking the hell out of mine with a cheater bar. not a good idea.
if you do all of this to no avail, you will need a new 103mm square taper bottom bracket (JIS taper.. this is important). the only one that i've found that is the FSA ultimax CrMo 68x103mm. It's a nice sealed cart bottom bracket and is only $34.00+s/h from www.aebike.com. The narrowest that the Shimano 53 or 73 model bottom brackets come in is 107mm. You can also find 103mm bottom brackets that have the campy-style taper. i would avoid those, but you may find some who use them with success. the FSA bottom bracket is nice, i use one.
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