Originally Posted by
Lazyass
To learn that, read my previous replies and then try to comprehend them. Do you know what the lowest possible q factor is with respect to the chainstay width restriction? Do you know the various q factor measurements from other cranksets? For some reason I don't think you do. .....
I might have said the same to you about reading posts, especially post No.45 where I showed by
your own measurements that the right side Q-factor was unchanged between the two bikes. (I suggested 3x that you measure the right side Q-factors, but I guess you prefer not to).
Of course I don't know the Q-factors for various cranks, and what's more I don't care. My point from the very beginning was that BB width isn't the determining factor.
The minimum right Q-factor is determined by the 45mm or so chainline requirement, and both are determined by chainstay clearance, and crank arm thickness. It's easy, and has been for decades to build bikes with Q-factors as low as those minimums, if that's the goal, and narrowing the BB does nothing to change that.
BTW- since I didn't know, I decided to measure the Q-factor on my sq. taper, 68mm BB Chrous road bike from
2001. Right side Q-factor is 71mm, (outside face of arm to centerline) and the left the same,
for a total of 142mm, which is lower than your "narrow" bike. There's plenty of room to bring the left in if I wanted to, but I prefer symmetry.