Well to be honest it was because my Klein already had 172.5 cranks and I use it for long flat rides and some centuries. Now granted it is a different geometry than my Specialized but it has been set up pretty close to the same. Crank Arm at the bottom to the saddle is the same. Saddle to mid bar is the same. The Klein is a standard road crank with a 52x39. The Klein is not as aggressive as the Tarmac and has a longer wheel base. I can hold the wheel longer with the kids up to about 27 or 28 for about 12 or so miles with no real climbs with the Klein but add a hill and it is like a ran into sand. I get winded at 30 and by 32 I am just about through. No they don't run that fast all the time but on the days we break out the A and B riders and the B riders are all riding together sometimes I will go with the As. Then on Monday nights we do a training climb just so they can practice for weekend races. I don't race because the masters are too fast and the cat 5s are too unpredictable.

I may just have to get used to the 172.5s but I thought the transition would be smoother because of the other standard crank.