Bottom Bracket replacement

[Wildernest69]

I am going to replace BB on my Rockhopper, the code on the spindle reads 3P, meaning that it is 119mm. Being that each side is different in length, would a BB from World Industries in 121mm be correct symmetrical length? Any other suggestions on replacing with a sealed bearing BB would be much obliged.
Thanx Wildernest69

[DaveM]

According to Sheldon Brown, 3P is a 68x119 spindle and the symmetrical equivalent would be a 122mm spindle (http://www.sheldonbrown.com/bbsize.html)
Unless your chainrings sit very close to the frame, 1 or 2 mm either way probably doesn't make a big difference. But make sure you get a BB made for a 68mm wide BB shell or it won't fit your frame well. I can't find any info on World Industries' BB. Also make sure you get a square taper spindle if that is what your cranks have.

[cyclerUK]

They may be a different lengths to account for the chainrings on one side.<br />
Have a look at the cranks and see if they are equidistant from the chainstays.<br />
(I generally work on the principle to use the narrowist BB that doesn't allow the inner chainring to catch the frame.)