Ypuh wrote: ↑Sat Sep 17, 2022 7:10 am

Hi everyone. I´ve got a question about the sizing of the C64. My physique is long in the legs (91.7cm inseam at 185cm length).

My ideal stack and reach is 610/395 with a 100 to 110mm stem (currently my frame has 396 reach with a 100mm/-7 degree stem and 42cm/70mm reach bars, could probably make a 110mm stem work too). If I look at the geometry table of a C64 you´ll end up with either a 56s, 56h or you can even make a 54h fit.

Since I don't really like the sloping looks on a frame this beautiful, I kind of don't want to consider the h-geometry. I also assume that if you add a headset topcap, you'll go over the 610mm so I'll end up with a 110mm/-10-12 degree stem.

Is 56s the best option and does anyone know how much spacers I would need (i.e. what is the height of the required headset top cap if you want to use Colnago's ICR stem)? From my own calculations it should work with about 5-7mm spacers if you include the mandatory topcap (+5mm) and

I also have long legs 88cm (cycling measured inseam where you stand against wall with "snug" bar under your crotch like saddle pressure) relative to my height 180.3 cm. Your arms also matter for ideal fit, as does of course your overall body posture and flexibility....

I am perfectly fit onto a 54s with 110-120 bars depending on reach of bars. I have almost no spacer under the stem and my stem is not the one for disc bikes requiring that extra space for routing cables. The drop of the bars is also an important factor. So, for the C64 rim brake bike I have short reach and short drop bars by 3T. The stem is your basic minimal negative which lines up about exactly with the top tube angle.

For comparison, I also race a Pinarello F10 in size 56 which is reach of 391 vs C64 385 and a shorter stack 569 vs 583 for C64. So, my F10 has a 1cm spacer and a 110 stem but my bars are a much longer reach 3T Aeronova. This is my race bike set-up though, not my ride 6 hours into the mtns bike which is more the C64 purpose. My mtns are in the Cascades WA state US.

Here is a convenient geo comparision tool for older bikes you might know more about your fit on vs the C64 sizing:

https://geometrygeeks.bike/compare/pina ... -2021-54s/
Unless you are seated very upright, I don't see how a 54 of any version would fit you very well. Yet, we do all have different bodies and my arms need room to stretch out forward and down. With my fitter we got my 5 hand/arm positions just right on my F10 by bringing my stem in closer but also lower and with the ENVE aero carbon stem that allows a for-aft adjustment of 2.5mm.

The 5 postions in order of aggressiveness/comfort:

1-comfort straight arms - hands on tops cross section

2-comfort straight-ish arms - hands on hoods

3-same arms but more hip flex puts hands in drops, can still ride here for hours, most of a criterium is here for example.

4-hands on hoods BUT arms bent maybe 60 degree such that forearms are resting "on" the bar sweep. The 3T Aeronova is perfect for this.

5-hands in drops again, finger tip on or near brake levers, but now arms bent for maximum aero, probably not here often, key moments, descents, etc.