Replacing bottom bracket - need advice.
 

I need to replace my bottom bracket, but need a little advice. I am replacing a TH Industries 7420AL in which one of the races disintegrated. I went to my bike shop and asked for a 68x118, which is what I understood to be the right unit for the BikeE. They sold me a Shimano UN73 Cartridge BB and said it was 118, but it is longer than the one I took out. I think it is a 122 and mine is 118.

Is there any problem with putting a cartridge in as a replacement for a non-cartridge?
Does the extra length hurt anything or do I need to track down a 118? There is only one chainring on the crank.
Is the UN73 a decent unit? It's on a long wheel base recumbent.

Any tips for when I put it back together? Is grease good or do I need antiseize?

Thanks,
Mike.

Have you measured the spindle on the old BB? The Q factor and chainline will be vastly different going from a 118 to a 122.

Near as I can measure, it's 118mm.

Thanks, I'll return the 122 and get a 118. Is it ok to put a cartridge unit in there?

yes, its fine

Un73s are good stuff. UN anything is pretty much gold.

there are 2 measurments you must be sure of 1 the length of the spindel and 2 the length of the bb shell if these match clean and face the shell before you install it and alway check your thread direction you don't want to cross threads

I've never seen a Shimano bottom bracket that didn't have the specs printed right on it. Usually in the middle of the barrel portion, between the two ends.

Bob

UNdeniably.

Phil wood ones are even better...

But a LOT more expensive.

better in price yes. If by better you mean more expensive.