So if I change my BB, the I can pretty much buy any crank/BB combination that will fit my 68mm English thread, keeping in mind that my current setup takes a 109.5-ish spindle? I really only need the compact for one particular 50 mile ride that has a 4.7 mile section of average 9% grade. I have already put on an 11-28 cog with my standard crank but I am hoping that a compact will make that climb slightly less miserable! The descent is pretty fun if not a bit scary! Thanks!