bottom crank problem - terminal or "we have the money; we can rebuild him" ??
07-30-15, 06:09 PM
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bottom crank problem - terminal or "we have the money; we can rebuild him" ??
Hi all,
This is what I found in the bottom bracket. The two questions I have are:
https://s926.photobucket.com/user/hec...cket%20problem
The spindle is a bit crewed in this one spot, but the faced cup, where the bearings rest has a crack/metal fatigue running almost half way around the cup.
Your thoughts?
Thanks in advance!
This is what I found in the bottom bracket. The two questions I have are:
- Can these parts be replaced, being a 25yr old Shimano GS200 on a 1990 Mongoose Alta? (yes, before Mongoose built crap bikes for the box stores)
- Can this be converted to a newer system? Any conversion is well beyond what the bike is worth monetarily, I understand.
https://s926.photobucket.com/user/hec...cket%20problem
The spindle is a bit crewed in this one spot, but the faced cup, where the bearings rest has a crack/metal fatigue running almost half way around the cup.
Your thoughts?
Thanks in advance!
Last edited by schlopartist; 07-30-15 at 06:20 PM.
07-30-15, 06:18 PM
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Looks like it's done for. Bring the parts in to your LBS and they should be able to find a replacement, either cup&cone or cartridge.
07-30-15, 06:27 PM
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07-30-15, 06:49 PM
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For replacement, you could swap it for a new Shimano UN54/55, or (for conversion) depending on the condition of the crank, swap the crank out, for say a Alivio M4000, although as the bike is from 1990, it may have a standard, not compact crank, which will complicate things with the chainring size.
07-30-15, 06:50 PM
#5
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A cartridge is the simplest way to go.
Look for a "code" on the spindle, such as 3-P, 3-S etc.
Scroll down a bit-
Sheldon Brown's Bottom Bracket Size Database
Look for a "code" on the spindle, such as 3-P, 3-S etc.
Scroll down a bit-
Sheldon Brown's Bottom Bracket Size Database
07-30-15, 07:38 PM
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Bottom Brackets are consumables, so it has little relevance to the worth of the bike today.
For replacement, you could swap it for a new Shimano UN54/55, or (for conversion) depending on the condition of the crank, swap the crank out, for say a Alivio M4000, although as the bike is from 1990, it may have a standard, not compact crank, which will complicate things with the chainring size.
For replacement, you could swap it for a new Shimano UN54/55, or (for conversion) depending on the condition of the crank, swap the crank out, for say a Alivio M4000, although as the bike is from 1990, it may have a standard, not compact crank, which will complicate things with the chainring size.
A cartridge would be spectacular! I intend to cross-country with this old boy and a cartridge would be ideal to a six-month maintenance lub cycle. I have explored YouTube and it looks very promising. Thank you!
07-30-15, 07:43 PM
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A cartridge is the simplest way to go.
Look for a "code" on the spindle, such as 3-P, 3-S etc.
Scroll down a bit-
Sheldon Brown's Bottom Bracket Size Database
Look for a "code" on the spindle, such as 3-P, 3-S etc.
Scroll down a bit-
Sheldon Brown's Bottom Bracket Size Database
I have found the code you mentioned. Thanks! It will save a lot of guess work on my part. Save me from looking incredibly stupid too.
07-30-15, 11:26 PM
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Your spindle does look a little rough. I can't tell with the cups, but you should be able to feel pitting. I'd replace for a generic Shimano BB. Or, you might find good spindles at your local co-op.
I did try to cut new bearing tracks in my Campy spindle using my lathe. Whew, it was HARD to cut. I did eventually get it ground down mostly, then reassembled and it seemed to work... at least for now.
One point is that if your choice is replace or not... then nothing you do can make it worse.
I did try to cut new bearing tracks in my Campy spindle using my lathe. Whew, it was HARD to cut. I did eventually get it ground down mostly, then reassembled and it seemed to work... at least for now.
One point is that if your choice is replace or not... then nothing you do can make it worse.
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