Using my very basic talents with a measuring tape, I came up with the following numbers: inseam 76cm, torso 64cm, forearm 34.5. I am 5’8" and weigh 152lbs. I am interested in a Saber. Would I fit on a 51 or be better served on a QR with a compact frame?? Thanks
The standard method is to multiply your inseam by .67 which with yours gives 76 x .67 = 50.92.
Based upon this, a 51 cm is your size. Top tube measurement IMO is actually the most imporant but there is not a formula that I’m aware to determine this. A 51 cm frame seems the place to start.
Cerveloguy is right. Top tube length is super important. So is the relationship of your femur length to the effective saddle/frame setback of the bike. All these proportions need to be in concert for the bike to feel “right” and perform optimally.
Check this out: These are the perfect fittng sizes for the following bikes for me. The purpose of this illustration is to show how differently the NAMES of the sizes (but not necessarily their actual dimensions) sound and look-
My perfect in the following model is:
Guru Trilite= 49cm.
Felt DA650= 52cm.
Cannondale IM2000/650c =52cm. (slightly high at head tube).
Cervelo P3= 51cm./650c.
Look KX Lite= 49cm (road frame).
Bianchi Mega Pro Triathlon= 55cm.
Notice the range of size names goes from 49cm to 55cm. The dimensions of each of these are close enough so that I can achieve the correct position using the appropriate handlebar/stem/seatpost combination and the bike stilll operates or interacts with the road appropriately.
What exactly is a Bianchi Mega Pro Triathlon? Is that the Chrono?