Does anyone know where I can find a chart comparing the Q factor (width from outer surface of each crank arm) of different manufacturers crank arms?
I should go round measuring cranks so i have a chart to go with the tube dimension and geometry ones.
Campag is 145.5 - all I need to know 
This may help a little
http://www.sheldonbrown.com/bbsize.html
I have DA 10 sp. on one bike and Ult. 10sp. on another. I’ll try and measure them tonight to compare.
I just moved from an older FSA carbon crank to the DA one and I’m convinced the Q is much wider on the DA one.
Shimano claimed that the Q-Factor didn’t increase from 9 to 10spd but it did. I think most external systems did increase the q-factor over whatever system they replaced.
That’s apparently part of why Campag took so long to release an external BB - had to find a way to match the Q of the Square taper crank/bb.
Looking in the FSA product managers guide the claimed numbers are:
I - Isis, M = MegaExo
Double 130 BCD
K-Force M 147
K-Force I 146
Superlight I 147 (they were awesome cranks - that was when I liked FSA)
Carbon Pro Team I 148
SL-K I 147
Carbon Pro I 149
G2 M 147
Energy I 147.5
Gossamer M 147
Gossamer I 147
Double 110BCD
Carbon Pro Elite I 147
(other models are same as 130BCD)
Track Cranks (Vigorelli) I 135
All the Triples are 159 -160
As it happens I have a gossamer MegaExo beside my desk and a pair of calipers (I’m starting to recognise that I have a problem) and they measure 147mm. bit of a surprise as I thought the Q would likely be like the weights - reality a bit different from on paper. Looks like we can trust all the numbers above.
I too have calipers and bike parts lying around my desk, it’s normal, really.
I’ll measure mine tonight, for now, i’m off to the pool.
You know what a PITA that is? If you have cranks laying around it is simple…otherwise you need to take off a crank arm and mount it in the same direction as the first to get a caliper on em…unless you gots one huge caliper.
I just measured my DA 10sp. cranks at 145mm. It’t not that big of a pain, you just take a straight edge and put it against the flat part of the cranks near where the pedal inserts. Then run the caliper across.