Which Bottom Bracket?

fatmcgav said:

Hey there,

I've just got hold of Carrera Kraken SE which is in need of a bit of TLC.
On glancing over the bike, i can instantly see that it needs a new Bottom Bracket.
Now my question is, what type of bracket is currently fitted to the bike, and what should i replace it with? I'm assuming it's a Shimano one-piece, as its full Shimano runing gear elsewhere...
Also, does anybody have any guides on how to do it?

Any help greatfully appreicated.

Cheers
Fatmcgav

Shimano Deore crankset?

I think it uses a ~118mm (?) square taper bottom bracket ... if you see a box-shaped end entering the crank arms, then the bottom bracket's spindle is square tapered.

If the spindle is ROUND all the way into the crank arms, then it is an octalink BB.

It's probably worth getting a "better" bottom bracket intended for an older LX-or-better level crank if you plan on doing a lot of riding -- something like a Shimano UN-73 (~$30US) if it is a square tapered BB ... only a few dollars/pounds more, but it will be a lot smoother, out-of-the-box, and probably last longer than the least expensive cartridge BB available.

Almost ALL Shimano cartridge BBs require a special tool ... the LIFU tool is cheaper (but, harder to find) and seems to be made of better alloy than the PARK tool.