Bicycle Mechanics - bottom bracket diagnosis and treatment needed.

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So the target bike that i have grown fond off has recently been facing minor health issues.
While riding, i have recently noticed noise coming out of my crank, and found out it was loose bottom brackett, so i go ahead and tighten it. In the process, however, i noticed that that bottom bracket was installed at an angle, and so the lockring wouldn't go on all the way.
So here is the question. I could take out the lockring, as well as the cranks and reinstall the bottom brackett. The trouble is that the mechanic at the local co-op said that if the threads are messed up from the first installation (target dudes) then i might not be able to get the bb in there again. He said that aluminum can not be re threaded.
First is this true, once aluminum threads are messed up they can not be fixed? i guess that would be my only question, because if it is then i guess there is nothing i can do with the frame anymore :( or is there??
Thank you for your assistance
Shanky
HillRider
02-28-08, 07:36 PM
The Target guys probably didn't do the damage as every complete bike is shipped to the retailer with the major items, particularly the bottom bracket already installed. The OEM is your culprit.
That said, you should pull the crank and bottom bracket and try to clean up the threads by "chasing" them with a tap. There may be enough left to be usable. If not, clean everything well, relube and treat the bad side with one of the Red (strong) Loctite grades. It should hold the cup adequately but disassembly in the future will be difficult to impossible. That should get you a season or two more out of the bike.
There are ways of salvaging a damaged bottom bracket shell such as retapping it to Italian threads which are larger. However, I really don't think a Target level bike is worth the expense or work.
Wordbiker
02-28-08, 07:44 PM
The Target guys probably didn't do the damage as every complete bike is shipped to the retailer with the major items, particularly the bottom bracket already installed. The OEM is your culprit.
That said, you should pull the crank and bottom bracket and try to clean up the threads by "chasing" them with a tap. There may be enough left to be usable. If not, clean everything well, relube and treat the bad side with one of the Red (strong) Loctite grades. It should hold the cup adequately but disassembly in the future will be difficult to impossible. That should get you a season or two more out of the bike.
There are ways of salvaging a damaged bottom bracket shell such as retapping it to Italian threads which are larger. However, I really don't think a Target level bike is worth the expense or work.
+1
Entirely accurate, nothing to add.
DieselDan
02-28-08, 07:48 PM
There are cartridge bottom brackets that thread back onto itself, rather then the frame. Stronglight and VP used to, and may still, manufacturer them. I used the VP version to save about two dozen or so rental cruisers that needed new BBs, but the threads got trashed when I removed the old cartridge BB.
operator
02-28-08, 08:33 PM
FFS people, stop crossposting. We already have a 30 billion reply thread on SSFG.
my apologies didn't mean to offend anyone operator. i just posted there to see what people would say. i usually post there, and realized that this would be a better place to post because people here would be best to answer the question.
The Target guys probably didn't do the damage as every complete bike is shipped to the retailer with the major items, particularly the bottom bracket already installed. The OEM is your culprit.
That said, you should pull the crank and bottom bracket and try to clean up the threads by "chasing" them with a tap. There may be enough left to be usable. If not, clean everything well, relube and treat the bad side with one of the Red (strong) Loctite grades. It should hold the cup adequately but disassembly in the future will be difficult to impossible. That should get you a season or two more out of the bike.
There are ways of salvaging a damaged bottom bracket shell such as retapping it to Italian threads which are larger. However, I really don't think a Target level bike is worth the expense or work.
Thank you this is probably the most helpful post i have read so far. I was planning to take the bb out at the co-op but i was worried that i wouldn't be able to stick it back in, depending on how bad the threads were. I had heard that aluminum frames can not be re-threaded, which was another concern of mine. But you are right i wouldn't want to spend a large amount of money getting a target frame re threaded. Now i'm not sure if that was the service offered to me. But the mechanic said they could overhawl it and do what ever they could to get it working.
But thank you, this weekend when i go home, i will take out the crank and if need be i will loctite the bb. I was hoping that i could put a new crank and bb on the frame becase it still hast he triple crank on it. Especially b/c i was getting use to the feel and had started enjoying riding it. But i guess if its time for it to go then its time :( makes me sad cause i can't really afford to spend more money on another frame, or atleast i can't afford to spend another 150 putting together a beater frame with the money i was saving for a track bike. ... :( very sad stuff.
Hopefully if okay if not will glue that puppie in there.
Thank you very much for the help.
Barabaika
02-29-08, 09:21 AM
I would watch craigslist.org.
Target or better grade mountain bikes often appear there for $15-100.
If your frame is shot, you can look for a bike that can be a frame donor. You can assemble it using the better parts from both bikes.
If you go to a bike shop, a bottom bracket job can easily cost $50 and more.
If you want to save the frame, I have another solution: drill a hole or two in the bottom bracket shell and bottom bracket cup, take out the bb, tap a thread in the shell, then screw in a short stainless steel bolt (cut it to fit). The bolt will keep the bb from unsrewing.
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