I currently ride a 56cm Trek and I am doing some planning on my next build. I was looking at the bikes of pro riders more or less my size and decided that Philippe Gilbert is my guy. While looking at his bikes I was a little surprised. As a 5'10" rider, he is using a 50cm frame!

It is somewhat acceptable for sprinters to go one or two sizes smaller but for a guy like Gilbert it looks weird. What's even weirder is that when racing for Omega Pharma Lotto he was using a 56cm frame.

Here are the two bikes:




and their respective measurements:

Canyon:

Rider's height: 1.79m (5ft 10in)
Rider's weight: 72kg (159lb)
Saddle height, from BB (c-t): 780mm
Saddle setback: 75mm
Seat tube length, c-t: 552mm
Seat tube length, c-c: 520mm
Tip of saddle nose to C of bars (next to stem): 587mm
Saddle-to-bar drop (vertical): 115mm
Head tube length: 150mm
Top tube length: 560mm

BMC:

Rider's height: 1.79m (5ft10in)
Rider's weight: 69kg (152lb)
Saddle height, from BB (c-t): 751mm
Saddle setback: 59mm
Seat tube length, c-c: 480mm
Tip of saddle nose to c of bars: 581mm
Saddle to bar drop (vertical): 122mm
Head tube length: 133mm
Top tube length: 535mm

Without even looking at the measurements, you can see the saddle setback difference. Both bikes feature very long stems (12 and 14 cm) and the saddle heights are completely different.

If you look at his riding position, not much has been changed and I think both look comfortable:



Does this mean that you can fit anyone to any bike? Is frame sizing a complete lie?

This guy is not some water carrier or peloton filler, he is the ex world champion and on multiple occasions the leader of his team. How can he have such different measurements on different teams?


Links for more photos and complete component list:
Pro bike: Philippe Gilbert's BMC TeamMachine SLR01 - BikeRadar
Pro bike: Philippe Gilbert's Omega Pharma-Lotto Canyon Aeroad CF - BikeRadar