Raleigh 20 / UN72 help, yet again

[pharnabazos]

I've searched and found different opinions when discussing the BB replacement, so could anyone tell me with certainty--can you use either 73mm or 68mm shell UN72 when replacing the Raleigh 20 stock BB? At one point I saw someone say that the only difference between the two was in the cups and not the cartridge, which is moot because you're not using the cups.

Thanks.

[Trocadile]

Have you already read Sheldon Brown on this?

Shimano UN72 With Phil Wood Rings
It happens that Shimano UN72 bottom brackets can also be used with Phil Wood retaining rings. The UN72 model is the only Shimano series you can use this way, because the other Shimano models have the right side threads machined into the cartridge body.
Unfortunately, for the 2003 model year, Shimano has replaced teh UN72 bottom bracket with the revised UN73 design. The UN73 is a fine bottom bracket, but it does not have a removeable mounting ring on the right side. The threads are part of the shell, as with the other Shimano cartridges, so the UN73 will not work with Phil Wood rings.

Phil Wood retaining rings don't have any shoulders on them, so they can be screwed all the way into the shell, even recessed below the edge of the shell. This greatly reduces problems due to the wider shell width.

http://sheldonbrown.com/raleigh26.html

(but I have no direct experience with this myself)

[pharnabazos]

Have you already read Sheldon Brown on this?



http://sheldonbrown.com/raleigh26.html

(but I have no direct experience with this myself)

Thanks-I've seen this, and countless other sites--they all mention you can use a UN72 with Phil rings, but I have no clue about the BB width, save for a post here by Cheq which mentioned that the width is the same for both 68mm and 73mm cartridge so it doesn't matter. Just want to make sure that's right.

[randya]

This is why I'm still riding the original BB / cottered cranks on my '20, even with a bent crank arm...

[juan162]

The 68mm and 73mm designations have to do with the width, or diameter of the BB, right? You'd think I would know this, since my buddy(an LBS owner) and I installed a un72, 68mm on my bike. It did work, but the Phil Wood retaining rings and the BB diameter were so close, that we had a very difficult time getting the BB to set exactly straight. In the end, we were able to do it, but with a lot of futsing. I think we may have overdone the tightening of the retaining rings as well, because the BB already needs replacing after about 2,000 miles. I am actually contemplating calling up a bike shop in England to see if I can get a FAG bottom bracket to replace it...since I'd be using the BB's own retaining rings, I figure it should be a better, easier fix, although a bit pricier than getting another un72 from here in the states. BTW, if anybody knows of any US store that sells FAG bottom brackets, please tell me. It seems like a much easier fix.
juan162

[pharnabazos]

The 68mm and 73mm designations have to do with the width, or diameter of the BB, right?
The 68mm and 73mm (which I was misleadingly calling the width) refer to the length of the cartridge, i.e. from the furthest left outermost thread to the furthest outermost right thread on the other side. The diameter of the hole is 1.37 inches, the standard width for English threading.

AAgghh! This sounds like such a headache! Maybe I'll just keep crankin' along, even though I've got this Deore LX crank burning a hole in my parts box.

[juan162]

Pharnabazos,
Don't give up yet...the 73mm is the better choice. I had to cut more threading and tighten the retaining rings like crazy. If I had had a 73mm, I probably would have had a much easier time of it.