Looking for bottom bracket recommendations

[Neil]

I used a un55 on my recent build, they are very readily available and do not have the nylon non drive side like the 54.

Didn't know a UN 54 had the metal cup. Thanks for that bit of info. I am not a fan of the nylon cups.

The UN 54 DOES have the nylon cup - that's what's said above.

It's the 55, apparently, that has the metal cup.

 

[bm0p700f]

Un55 -metal cup cheap as well.

 

[Inzaman]

I used a un55 on my recent build, they are very readily available and do not have the nylon non drive side like the 54.

Didn't know a UN 54 had the metal cup. Thanks for that bit of info. I am not a fan of the nylon cups.

The UN 54 DOES have the nylon cup - that's what's said above.

It's the 55, apparently, that has the metal cup.

That is correct, my 55 had a metal cup where as the 54 has a nylon cup. The bb that the 55 replaced was some LP26 thing and that had a nylon cup. I thought nylon a cup was a more recent thing but obviously not.

My thought process behind the 55, aside from the cost and the metal cup, was that the XT is a 72 many years ago so with this trickle down technology the 55 must be the 72 equivalent now? I could be wrong but hey the 55 seems to work well and is certainly better that the bb it replaced

 

[hamster]

Does the 55 have the hollow shaft like UN70/71/72?

 

[bm0p700f]

I think it's more the UN72 is no longer made and the only shimano square taper chain set sold are alvio or lower. Therfore in Shimano's reasoning they no longer make anything above the UN55 as they do not chainsets to go with them. Why support there older kit when Shimano want's you to buy a new XT cransket with external BB. Retro bikes is a small part of the bike market.

 

[FluffyChicken]

Does the 55 have the hollow shaft like UN70/71/72?

From what I can remember it does, as does the UN54.
The UN54/55 is a step up from the other UN5x's but a step below the UN7x's
More like a UN6x I guess.

shimano's official response to me about the difference between the un54 and un55 was just the switch to the metal cups.

 

[Dossa]

UN54's get a hard time, but I think they're fine, no issues using them whatsoever

 

[Neil]

UN54's get a hard time, but I think they're fine, no issues using them whatsoever

The only thing I don't like about them is the plastic cups.

And they're probably perfectly serviceable, I just don't like the idea of using plastic ones.

 

[Thunderchild]

I decided to try a square taper Tange Seiki IRD bottom bracket. Pretty good price; if it lasts that is. I will report on it after a few hundred miles.

Thunderchild