Shimano UN54 and UN72 alternatives
 

I'm looking for a 68x115 shimano bottom bracket and the UN54 appears to be my only option I can find. Can anybody suggest other bottom brackets I could use? I'm not a fan of the plastic cup on the non-drivetrain side, so I'm trying to find something more like the UN72's alloy cup on the non-drive side.

Help me out?

Miche Primato. It installs just like a Phil Wood. There's nothing wrong with that plastic ring on the Shimano, though. It's plastic to prevent creaking. I've never had one break.

will the metal cup from the un72 fit? See a bike shop, they'll let you check it out to measure, and will probably have an extra metal cup to sell you cheap.

There's no logical reason to avoid the plastic bb cups if you use the appropriate torque on it. They are better than the metal cups in that it doesn't creak.

See, I have pretty much the same BB on my bike now, and I think the ring is what's causing the creaking on the non-drive side. It's driving me bonkers.

And mine has cracked. I have never adjusted the cups on a new bike and noticed the crack when it became apparent the BB did not hold as tightly as it should. I have since avoided plastic for holding a BB.

Otherwise, xxcycle:

http://www.xxcycle.com/index.php

has Stronglight and Token BBs.

How about the Tange ones that IRD sell?
http://www.interlocracing.com/bbs.html

grease is the word!
 

did you grease the inside of the plastic cup?

And the only reason it would crack is because of improper installation, overtorque.

Sure, but it is also an issue of how much tolerance is left for error and also the possibility of part aging. The material should be, of course, best softer than the the shell, but it defeats me why Shimano might make one side of plastic while the drive side out of steel. I live happily with both sides out of alu and really have no interest of testing how many screwings and unscrewings the plastic could live through.

I don't like the plastic cups either and have cracked several, but all have been my error. Once installed, they have been problem-free.

Could somebody write down the proper procedure for installing a Shimano BB with a plastic cup? I'm about to install one, but all these reports about cracked cups make me nervous.

I take it the threads in the BB should be free of dirt and rust, and slightly greased. Do I first screw in the plastic side, and then the drive side? Tips are appreciated.

^^^^

This should help.

http://www.parktool.com/repair/readhowto.asp?id=94

Driveside first, greased, good and tight. Non-drive side, greased, just snug it down. I've cracked a couple myself. On my search for compatible replacement cups (not an easy task, as the sizing on these things are not standard, it seems) I had several shop mechanics tell me just to snug it down.

I am also looking for alternatives to the plastic cups. Any suggestions? I need to to replace a Shimano UN-54 (68x118mm) but I want to try something else.

You like that creaking sound on every pedal stroke ?

How 'bout this? http://www.universalcycles.com/shopp...3&category=347

Velo-Orange bottom brackets are very nice. Lighter than Shimano and a hollow spindle so you can use a skewer to hold the tool on while you install it.

How about a UN 55, I believe it has an alloy cup instead of plastic.

QBP has an 'Up Cup', they got it made in aluminum,
it's an aftermarket buy to replace the plastic ones
seen here :http://www.universalcycles.com/shopp...&category=2634

$20!? In the past, when I was looking for a metal cup for a Shimano BB, I was offered a replacement one for $4 or $5 at my LBS and, in my memory, it was made by Shimano.

http://www.biketoolsetc.com/index.cg...r-Spindle&q=&s=