I want to change the crank arm length on my Bianchi 928 CF bike. The current set up is FSA ISIS drive Double Compact.

I have no problems with the BB or the FSA Compact and have located a crankset of the length I want in ISIS at a good price so I'm inclined to buy them and I'll have a spare set of chainrings for future use.

My concerns are:

Mega Exo and other external bearing BB set seem to be more prevalent, the current choice. Is ISIS drive on the way to obsolescence (at least sooner than the external bearing BBs) and will it be hard to find in oh, say, five years when it may be time to replace it?

I think I may want to have the BB shell faced before I install this hypothetical BB. What is a fair price to pay for this? This needs to be factored in to my budget.

I am not a sprinter so the stiffness I hear about with the Mega Exo is probably not a a big deal to me. Durability is. Is there a difference in usable life between the BBs? Is the external bearing easier to service?

Thanks!

I used ISIS for several years and had no problem with it, but many users have. It's definitely on the way out. FSA outboard cranks also have had their share of problems. One of the most common designs uses one center fixing bolt on the left crankarm and a tapered spline on the left side. There have been plenty of problems with those cranks. FSA resorted to recommending a specific loctite product for the splines and another for the fixing bolt threads.

ISIS BBs are really not serviceable, you just replace it if it dies. Pretty much the same for outboard BBs, although you can press out the bearings and put new ones in, with the right tools.

I don't think anyone can predict how long ISIS BBs will be offered. I'd either stock up on BBs now, or buy something that has a better future.

FSA has redesigned some of their cranks to use 6mm wide bearings instead of 7mm and added a wave washer to set the bearing preload, to eliminate the problems with some of their early model cranks.

If you're going to get an external crankset, get shimano - the mega exo bb's are shyte as are most of FSA's low/mid end cranksets. I doubt you will need to have the BB faced - but if necessary expect to pay anywhere form $20-$40.

I highly suggest not buying into FSA cranksets. They really, really do suck.

Part of my thought process is to get rid of the FSA crankset entirely. The rest of the drive train is Campy 10sp and I'm inclined to replace it with a Campy crankset and BB but the FSA is doing the job so far. I just want to get rid of 2.5mm of crank length right now and that will cost about $72 shipped and give me some spare chain rings.

Thanks for the input.