Bicycle Mechanics - Fixed cup on my fixed gear needs fixing!

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progre-ss
06-29-04, 04:28 PM
I was out on my lunch hour ride today, barrely 5 minutes from the office when I hear a clunk from my cup and cone BB. I stop to look at it and notice my fixed cup doesn't seem to be fixed anymore. The flange of the fixed cup looks crooked. I'm thinking that when I was installing the cup I overtorqued it and somehow stripped the threads. Can the BB shell be rethreaded or am I SOL? I'm really attached to this bike and seeing as I have little money to spend, buying a new frame may be out of the question. Seeing as I'm also short at 5'6", this 49cm frame fit me perfect and inexpensive track or fixed frames are a rare breed (from what I've seen anyways)! If I can't rethread the BB shell, is there any way that Red Loctite would hold or perhaps even JB Weld? Or what if I got someone to weld the fixed cup permanently....

Here's a pic of the fixed cup from above:


DieselDan
06-29-04, 09:06 PM
If one can be found, Stronglight used to make, and may still do, a cartridge BB that does not tread into the frame, but is secured by retaining nuts on each side of the cartridge aganist the frame. The BB has to faced by an LBS for one to work.

madpogue
06-29-04, 10:07 PM
One can hope that maybe the shell is fine, it's the cup that's got the stripped threads (unlikely, yeah, but one can hope...). Can you get your mitts on a replacement BB, maybe a cartridge, temporarily, to see if it'll thread in normally? This might be an opportune time to go to a cartridge BB anyway.

(Otherwise, I suppose you could say the fix is in [ouch!])


progre-ss
06-30-04, 09:39 AM
Thanks for the replies guys.

DieselDan: Is this what you were talking about? http://www.zefal.com/stronglight/page.php?nom=produit&keyProd=jp1000 Sounds interesting...we'll have to see how everythiing looks after I remove the bb today.

madpogue: I've got a cartridge BB that I'm gonna try and thread in today at lunch (boo, no lunch hour ride today!). Hopefully I just stripped the threads on the cup and not the shell.

progre-ss
06-30-04, 03:50 PM
Today at lunch I took the BB out and then cleaned everything up. Threads on the fixed cup seem fine and there seems to be a little stripping on the threads in the shell although when I went to put the fixed cup back in it seemed to have held pretty well...that is until I put the adjustable cup in. When I tightened down on the adjustable cup, I guess it was enough force to move the fixed cup a few mm outward. So I guess it's stripped. The stronglight JP1000 is the BB for use with screwed up threads so I may go that route. The only thing is the BB shell has to be faced at a 45 degree angle before installation. Can't seem to find a price on it though. Either that or I'll JB Weld the fixed cup to the shell. Thanks for all the help guys!

John E
06-30-04, 04:01 PM
Assuming your BB shell is NOT Italian-threaded, you may be able to have it redrilled and retapped Italian, which uses a 36mm diameter instead of everyone else's 35mm.

DieselDan
06-30-04, 08:13 PM
That's it. The bottom bracket to save a hosed shell. It doesn't thread into the frame, just held into place with the two large nuts. You just need to get the BB shell faced.

progre-ss
07-01-04, 02:55 PM
Well, went ahead and bought the JB Weld last night after work. I doubt any of my LBSes would have the Stronglight BB in stock and I couldn't be sidelined from my bike whilst I wait for it to arrive. I am a bit impatient when it comes to my bike and not being able to ride it. Anyways, I mixed up the JB Weld as instructed, cleaned up the fixed cup and BB shell, and then applied the mixture to the threads on the fixed cup. I let the "weld" cure on the drive home as well as overnight and then put the rest of the drivetrain back together this morning when I got to work. I was having a bit of trouble with the adjustable cup so I took my time reinstalling it as to not **** up those threads too! While I was at it I replaced the 42T chainring with a 48T. Took her for a spin at lunch and it felt good... no creaking, no movement at all coming from the BB. JB Weld rocks! According to their website, some drag race guy used it to fill a crack in his cylinder head and it earned hima second place finish. I'm sure it'll hold on my BB. And in regards to the 48 x 14 gear? Damn that hurts at times! Mainly at lights and uphills. Again thanks for the suggestions and help.