EDIT: I realized this is much more suited for the Bike Mechanic forum. Feel free to ignore this as I can't figure out how to delete it! My apologies.

Hey all,

I'm currently doing a few upgrades / cleaning up my (new-to-me) old Trek 1400 (possibly an '89? Blue with white decals).

I decided to take the bottom bracket off so I could clean the inside up so it doesn't get jammed in the future (it took a some overnight soaking and leverage to get the drive side off) and the non-drive cup is totally thrashed (not my doing).

I'm wondering what my best route is for replacing the cup. Current BB is a UN52 68 113 (1.37 x 24 - Don't think this is necessary but more info is better I suppose).

Should I just buy a new cup (UN54 cup) like this for about $14:

Amazon.com : Shimano UN54 Left Bottom Bracket Cup (68-mm BSA) : Bottom Bike Brackets And Accessories : Sports & Outdoors

Or am I better off spending $24 for a brand new UN55 for $24:

http://www.amazon.com/Shimano-Tapere...bottom+bracket

At the moment, I'm unsure the differences between a UN52 and UN55 (55 has metal cup and better internals?) as I haven't found much info on the UN52. I'm going to do some more research, but I was hoping you guys might know the answers to my more "specific" question on whether to upgrade or go for the cup. As far as I can tell, there is no damage to the UN52 other than the cup.

Thanks,

Alex