Advice on Colnago C59 Geometry

[airwise]

I would go so far as to say the differences are imaginary and would bet my house that you couldn't tell the difference without knowing which you were riding. But the main thing is you enjoy your ride and that's all that counts IMHO.

[Colonia]

Sorry but that's incorrect. Or at least it's worded in a way so as not to make the point you intend. There is a 0.6 deg difference in ST angle.

If you position the saddle in exactly the same place in relation to the BB as you would on a 48s, thus not affecting your seating position, the effective reach will be at worst +3mm than the 48s.

In my case I can get virtually an identical position on a 54 std, a 52s or a 50s Colnago.

It is not incorrect at all. 1 degree in STA equals about a cm on the top tube. I don't know the headtube angles on the two frames (do you??), but we are looking at about a half centimeter increase in reach.

Furthermore, the larger bike technically requires a larger stem to keep things in proportion. If the rider is more suited to the 48s, this will be a problem. Same issue if the rider has a short femur and runs out of saddle rail when moving the saddle farther forward (on the 50s) to account for the slacker seat tube angle.

[Colonia]

deleted double post

[Colonia]

A point many lose, is that Colnagos are frames made with italian racing geometry.

That means low bottom brackets, slanted head tubes and shorter top tubes.
They are thought to be setup, on "long and low" stems, so your weight would be properly balanced.

I have had Colnagos ( C40s, C50s, EP, EC ) on sizes 54,55,56, 56 "freuler", 52s, 57 and 58

I can sure get the exact same fit on all those by using the right combination of stem and seatpost seatback.

But the one that really fits, handles, climbs, descends and rolls perfectly for me is the 56 traditional on a 120mm stem, (-6° no spacers, or the equivalent fit on -17° ). It simply puts me on the right place. no doubt about it. Coincidentally this fit is "balanced" so I have exactly 56cm "Saddle-tip-to-center-bars" and 56cm "center-bars-to-center-front-hub".

Some people don't know that and tend to set up their Colnagos on "short and high" stems and that is IMHO wrong. even more with compact bars with the shifters pointing up. While that setup can be right on an american geometry sloping frame, they are not good for the italian traditional geometry.

there is an interesting read on RKP about this here

http://redkiteprayer.com/2009/10/a-study-in-geometry/" onclick="window.open(this.href);return false;

Can we put this myth to bed? Italian stage-race geo is described in detail in the CONI manual, and that geometry is largely unchanged on today's Italian bikes. The long and low thing is bollocks. For example, a 56 cm Colnago should run a 9.5-10 cm stem based solely on frame proportionality (body morphology can dictate otherwise, of course). You can also see how this works just by looking at a bike: look at where the end of the bar (curve) ends up in relation to the front hub -- with a proportional stem, it will sit right over the hub.

Super high bars with shifters pointing way up usually just indicates a missized frame --- likely due to an error in seat height. And, generally, regarding shifter position, compact bars are a different world than trad. bars.

[kulcha]

Hi Colnago gurus,

Apology to bring up the thread again. Gonna pull a trigger on a C59 and I need some kind advices as I think I am stucked in between 45s or 48s.

My measurements are as below:
Height 173cm
Inseam 78cm
Saddle to BB 67cm (140degree kneed angle)

Thanking you in advance!

[mpower]

Hi Colnago gurus,

Apology to bring up the thread again. Gonna pull a trigger on a C59 and I need some kind advices as I think I am stucked in between 45s or 48s.

My measurements are as below:
Height 173cm
Inseam 78cm
Saddle to BB 67cm (140degree kneed angle)

Thanking you in advance!

Get a 48s.

[kulcha]

Hi mpower,

Many thanks for your prompt response. I actually tried on my friend's 48s over the weekend for >100km. With my measurements, the seat post looks short on the 48s and I felt that I was a little over-reach on my friend's 120mm stem.

Though I took out the spacers and slamped the stem slamped, I think I could still go down further for more aggressive position.

FYI, I've been on TT for more than 2 years and I'm planning to get C59 to join my friends in weekend group rides.

I think with 45s, I can get a better stack and reach, who do you think? Is there any way I can find C59's stack and reach? I could not find them after much search.

Thank you again.

[mpower]

I have almost the same body specs as you except with 170cm height and 76cm inseam. Both my C59s are in 48s and are with 68cm saddle height from BB center to saddle top as per the photos. I also run 110mm stems with 420mm center to center handlebar. The reach is also 40cm. They both look ok to me with this saddle height.

A 45s would look very 'compressed' to me.

Hi mpower,

Many thanks for your prompt response. I actually tried on my friend's 48s over the weekend for >100km. With my measurements, the seat post looks short on the 48s and I felt that I was a little over-reach on my friend's 120mm stem.

Though I took out the spacers and slamped the stem slamped, I think I could still go down further for more aggressive position.

FYI, I've been on TT for more than 2 years and I'm planning to get C59 to join my friends in weekend group rides.

I think with 45s, I can get a better stack and reach, who do you think? Is there any way I can find C59's stack and reach? I could not find them after much search.

Thank you again.

[kulcha]

Thanks man!
You're Ah Keong's brother right? I can recall that I saw this photo in his FB.
Cheers!
Good to see u here

[mpower]

Thanks man!
You're Ah Keong's brother right? I can recall that I saw this photo in his FB.
Cheers!
Good to see u here

[gilldog]

If it helps i have just pulled the trigger on my ultimate build c59.
I'm 5'8 and have a 50s ,100mm stem, short reach bars and a 25mm layback Colnago seat post. I was worried that it may feel to long but if anything it feels shorter than my 54 Cannondale synapse with the same vital statistics.

It had a maiden voyage up the road on sunday and first impressions are that on the tops it feels quite short but in the drops and hoods feels long in a good way. It has taken me about 3 months all in all to build it, i studied every forum and measured every frame i could find to assure myself i have the right size. However in the end you have to pull the trigger and make do with your purchase as test riding these things is an extraordinarily difficult thing to do. and even if you do miss size you can take some solace that the pros are running smaller frames with longer stems and larger seat post set backs so there is always room to tweak it.

Believe me the sizing will be long forgotten the moment you try and chase two unguided gear cables through the frame when you build it. (i found a torch and a specially made cardboard hook torn from a cereal box did the trick in the end)

i must post some pictures

[kulcha]

Thank you very much all!

I spent whole night reading this forum and other sites and I had decided to go for 45s

Now I must find a good reason to convince my gf, "look my cyclist buddy bought wrong size and it fits me and it is 50% cheaper"

[PSM]

I would also say a 48s. But I didn't spend the whole night...

[shimmeD]

I'd go for the one with the shortest head-tube and slam that stem.

Only that there's hardly any difference in between the two, and they're both too much for me in any case.

I have virtually identical inseam and seat height.

[quinner]

I think 54 is equivalent of 50s?

Agree 52s or 56 would be your size.