What size bb do I require?

Truvativ cranks / chainset.

Cheers.

errm – do you mean what length axle on the BB?

sq taper or Isis?

it's dependant on the cranks not the frame though.

68mm bb shell, and as above if they are isis or square taper cranks it depends on the crank arms (try googling the model).

Sorry, Isis.

you probably need to get the exact crank model and check on the truvativ site. likely to be either 108 or 113 though.

Mine needed a 68 x 108 (bit of an unusual size combination I think) – but I think the 108 axle was specific to the Crankset, which was a raceface evolve.