My bud has a 53 I think, might be a 55, but you'd have to pry it out of his dead hands/clipless before he sold it!
I'll ask anyways!
L8R
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"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming, "WOW, What a Ride!" - unknown
"Your Bike Sucks" - Sky Yaeger