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Bb Troubles


trialsguru

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well ive got a slight problem, i checked that my bb was tight today and went to give it a little nip up , whilst tightening the drive side half of the part of the cup the tool sits in sheared off! im worried i might not be able to get the bb out if the rest shears off resulting in a ruined frame.

has anyone else had a problem like this with a bb?

also will it still be ok to ride on? i put lock tight on the threads when in put it in so im hoping it should be ok and wont come loose, its just i wont be able to get a new bb before sunday.

thanks for any help

pete

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mine did exactly that, it sheared right off, fortunately the guys at tarty (total f**king legends) mannings fault.

if you can get the other cup undone, you can undo it with your fingers, well i did...

yep, luckily i just got it out.

ash did you get a new one under warrenty? assuming yours was an skf right? just cant see why it should shear off like that

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If you havn't faced the frame, they might not do warranty.

I'm loving my SKF BB.

It is true.... you should never need to locktight your BB on and shouldn't really use any old grease. You should be using anti-seize or build-up grease so that you can get in undone. Sealed units shouldn't come undone but it happens.

Rob

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If you havn't faced the frame, they might not do warranty.

I'm loving my SKF BB.

Sealed units shouldn't come undone but it happens.

Rob

lol i only put loctite on the threads of the bb, i.e contact between frame and bb, that has nothing to do with the bb being a sealed unit.

anyway, more to the point it looks like this isnt a one off so hopefully i may have some luck.

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nah, bb's arn't really subjected to enough turning forces to remove them under normal riding if they have been installed correctly in the first place.

I'd say it's more likely that your's had some sort of anti-sieze compound on the threads rather than locktite. Sealed devices like the SKF shouldn't need greased either, where would you put it anyway?

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anyway less about the loctite lol its not exactly like i put chemical metal on it! loctite isnt the cause of the bb breaking in the slightest. does anyone have the leaflet you get with skf bb's to hand? i cant find mine. does it say anywhere in it about having to have you bb shell faced before you fit the bb?

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anyway less about the loctite lol its not exactly like i put chemical metal on it! loctite isnt the cause of the bb breaking in the slightest. does anyone have the leaflet you get with skf bb's to hand? i cant find mine. does it say anywhere in it about having to have you bb shell faced before you fit the bb?

Manufacturers generally recommend facing your BB shell before fitting any bottom bracket

EDIT: and chasing the threads.

Edited by Shaun H
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1.) Clean both threads of the frame from rust, dirt and varnish

2.) Apply bearing grease or anti fretting paste to both outer threads of the bottom bracket unit and the surface below the threaded sleeve

Nowhere does it say anything about frame facing

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hehehe i like this thread.

Face off the headtube at the same time (Y) that will stop the b/b coming loose (thats as random as most of these posts!!!!)

if the cup has broken, iv not seen it much it may be due to over tightening. but its best been in tight than coming loose every 5mins. iv only ever seen lovatt break a driveside b/b cup (and it does come out easy after the left hand side is pulled out.)

the debate of facing b/b and such forth is not a big issue, iv had numerous frames with alot of paint around the b/b area and it doesnt really affect it unless the 1st few threads of the b/b are painted,and the b/b wont go in straight, then they need the b/b thread tap running through. (chasing the threads)

chasing the threads. where to? :P:lol: wouldnt fancy chasing them to Taiwan (BTW the 1st line and this line is a JOKE! a bit of humor)

Waynio..........................

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thank you wayne, likewise ive never bothered facing bb shells nor have i ever snapped a cup before and i certainly cant see it being because of a little paint.

looks like ill just have to see what pace say.

p.s has anywhere got skf bfr 300's in stock? 118mm or larger

thanks

pete

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Paint isnt the issue. When I had problems with a zona zenith and SKF, a dial gauge showed the ends of the shell were 15 thou out of square with the bore. That and the small amount of metal around the bb flange area caused it to fail. Faced the shell and fitted the new BB very tight, no suspicion of a problem.

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What does it matter if the bb is against a flat surface or not?

Aslong as it's on the threads I just tend to wind them on, fair enough, It might not be a perfect fit, in that the face of the BB shell is not parallel with the BB itself, but does it actually matter?

Surley as long as the threads are straight, and your on them, if you tighten it up nice n tight it's not going to move out of line when it's screwed so far in the BB shell......???

Correct me if im wrong, but did it really cause you problems with the zenith?or could id have gone on anyway? I know personally i'd probobly have done the same, even if it could have just been wound on anyway.....

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Sorry for going offtopic but what's wrong with using loctite? The bb in my old frame kept coming undone, flooded it with Loctite 270 and after half a year fairly happily unscrewed it.

Most bb's come with a thin layer of loctite substitute applied to the cups anyway.

I guess a bb can bond itself to the frame when there's water in the threads?

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What does it matter if the bb is against a flat surface or not?

Aslong as it's on the threads I just tend to wind them on, fair enough, It might not be a perfect fit, in that the face of the BB shell is not parallel with the BB itself, but does it actually matter?

Surley as long as the threads are straight, and your on them, if you tighten it up nice n tight it's not going to move out of line when it's screwed so far in the BB shell......???

Correct me if im wrong, but did it really cause you problems with the zenith?or could id have gone on anyway? I know personally i'd probobly have done the same, even if it could have just been wound on anyway.....

All I can say is what happened. Screwing down the bb caused the flange to fracture. When I inspected it, I found it had fractured at the point where the frame was most out of square. Being a machined yoke, I didnt think it could be that far out of line. Cleaned the paint off and set up a DTI to measure the run-out. It was so far out that I had the shell faced, then after there were no problems. I'm sure a Yorkshireman will be along shortly to tell me I'm talking out my arse, but that was my problem and I solved it that way.

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