Quote Originally Posted by rm -rf View Post
Stack and Reach
I used "stack and reach" from the bike's Geometry charts to compare some new bikes with my previous bike. I get a good idea of how each frame will affect stem length (via reach) and steerer spacers (via stack).

(Higher bars will somewhat affect stem length, since the rider isn't leaning forward quite as far.)

Your 56cm Supersix is stack 56.7, reach 39.3 cm.

A 56cm Cannondale Synapse carbon is stack 59.0, 38.6 cm.

BMC GF02 in 56cm: stack 58.0 reach 38.4 cm.

Chainstay length, from bottom bracket to axle, are all similar, with the Supersix 56 around 406mm and the Infinito 57 at 411mm, and the GF02 at 412mm. The Synapse is somewhere near 413mm. So these aren't long wheelbase touring bikes at all.

Bianchi Infinito
55cm stack 56.7, reach 38.1
57cm stack 58.3, reach 38.6

My Infinito CV has what I thought was a taller head tube than "race" bikes. But it's not all that different than your Supersix.

Compared to your Supersix, the 57cm Infinito has a 16mm taller stack, and 7 mm shorter reach. That's 1.5 10-mm spacers taller, and less than 10mm in stem length.

The frame feels stiff to me, making for precise handling. The road buzz vibration canceling works, and I think it helps to keep the bike stable on very rough surfaced turns. (And there's even room for 28c tires if you ride long days on rough roads.)

Worth a test ride.

Max spacers
I think most carbon steerers recommend no more than 40mm of spacers. (I thought some were 30mm max?)

That's 4 10-mm spacers.
Subbed for this post to use it as reference.