Cannondale SystemSix size 51, I like long front center

[Hexsense]

Introduction
Years ago I was on Allez Sprint size 49 with short wheelbase. And life is normal. Using slammed 120mm stem, I have to scoot back a bit on the saddle before cornering hard.
Then one day, I got Supersix Evo 2020 size 48. Eventhough the reach is about the same, the front center length is lengthen from 566mm to 588mm.
And that's the revelation... My bike feel much more balanced and in control. I don't have to scoot back to corner anymore. I'm very happy with the change.
Then...
If more is better, even more is even better, right?
I decided to find out.
I bought Cannondale Systemsix size 51. It has practically the same stack height as Supersix size 48. But even longer reach and front center. The front center is so long that it's longer than Tarmac SL7 size 56! Whoa, nicee.

Frameset Preparation:
Since I just want to find out if it's better than my Supersix. I'm not going to buy a new complete bike or frameset. I managed to scavenge a used frame on Ebay in the size 51 I need. However, the frame is in BBQ black color. And I hate all black bike both from safety and styling point.
So...
I have to change the bike color. But I don't want to repaint which will kill the resale value of this frame if I don't like it.
Therefore, I learn how to apply vinyl stickers, use knifeless tape to do clean cut on the vinyl and start adding color to my bike frame.
I added red and blue color to the frame. Then changed lettering and Cannondale logo to glittinging flip color.
Ref: How to use knifeless tape to cut vinyl on the frame https://www.youtube.com/watch?v=UWqIBnr-1yg
Ref2: How to vinyl over logo and text decal on the bike https://www.youtube.com/watch?v=0FEBkAP3KBo

[Hexsense]

Build:
This is quick. It's a component move over from my Supersix. Except using new bar that I want to try and 10mm shorter stem (110mm instead of 120mm).
New brake hose as I leave the old hose there just in case I want to revert back to Supersix.

Brief component summary:
38cm Coefficient RR handlebar
110mm -17 degree Bontrager Blendr Pro stem. I could save more weight here as I no longer need Blendr mount with this handlebar.
165mm Quarq Dub D1. Rotor chainring for the deep aero look.
Mostly Ultegra Di2 11 speed with Dura-ace FD.
Galfer rotor. It has a low profile look. Sometime blend to the background which I like more than having eye-catching discs.
Leverless axle from SuperSix.
Light-Bicycle AR56 front, WR65 rear wheels on Carbon-ti hubs.


My SuperSix non hi-mod was 7.2kg and My SystemSix ended up almost 7.5kg.

Ride Comfort:
On the first ride, I miss my Supersix...
This thing is rigid. Seatpost flex less, fork and bar flex less. It remind me of Allez Sprint ride quality...

On the second ride, I drop tire pressure on my 25c front tire on 23mm internal width rim and 28c rear tire on 25mm internal width rim from 58psi down to 55psi.
And the comfort is nice again. Aero bike can ride harsh, but lower tire pressure can cure it.

Handling:
Yes, I notice that the bike is longer. I'm 5'6 rider that use stem height so low that most bike size 52 is too tall, yet this bike has the front center length that is longer than other race bike size 56.
From Supersix with 588mm front center to Systemsix with 595mm front center, I think it reach the point that I don't feel benefit of lengthening front center anymore.
It definitely still ride better than short front center of Allez Sprint. But I can't say longer is better, over the Supersix's already long front center.
Overall, I still like that I only need 110mm stem rather than 120mm. But it isn't a big positive change I experience going from Allez Sprint to Supersix.

Aero?:
SystemSix doesn't really "feel" faster on headwind or tailwind.
But it "feels" more aero in the crosswind. This is a little surprising. I thought slim tubing with less side profile of Supersix would save me energy as I don't have to fight crosswind as much. But it turns out, that deep tubing of SystemSix is doing the sailing job when the wind hit from the side. Yes, there are more force pushing bike to the side. But my bike is so long that it's really stable anyway. It probably is even easier to control now because the deep frame tube catch wind the same way as deep wheel and counter-act the steering motion. Unlike on my Supersix which virtually have no side profile frame vs deep wheels.

Overall:
I keep the change, and will sell Supersix frameset.
It ride less comfortable. The extra length sadly isn't as overwhelmingly positively noticeable vs Supersix. Unlike when I switched from Allez Sprint to Supersix. Regardless, it's still not a negative change. I also like that I can now use (-17 degree) 110mm stem instead of (-17 degree) 120mm.

[romanmoser]

Great experience thanks for the return
Pro stealth light saddle ? Old one flatter or curved new one ?
Really intrigued by these bars

[Hexsense]

In picture is Syncros Belcarra V 1.0 tt saddle because it allow more forward seat location.
But I have since switched back to my trusty saddle, the SQlab 612r. It set me more rearward on the bike than Syncros saddle, but that's fine.

[trainergav]

It's crazy to me that the 48cm Supersix and 51cm SystemSix are so similar in size. I would have expected lots of variation between brands but not for 2 similar era bikes from the same brand. And the Cannondale size calcuator doesn't seem to notice the difference.

[overdriven98]

personally I like it short, I hate the feeling of driving a bus

[Hexsense]

I think trail value and chain stay length have more effect on feeling of driving a bus.
In this case, 58mm trail and 405mm chainstay. Both are as racy as it gets.

It's crazy to me that the 48cm Supersix and 51cm SystemSix are so similar in size. I would have expected lots of variation between brands but not for 2 similar era bikes from the same brand. And the Cannondale size calcuator doesn't seem to notice the difference.

For the equivalent size number, they are equivalent in reach. But SuperSix's stack is lower.
So, 44cm Supersix is as tall as SystemSix 47. 48cm Supersix is as tall as SystemSix 51, etc.
SystemSix 51 is still 7mm longer in reach than Supersix 48 so they aren't that similar.
Most people size their bike by reach. Just not me. I'm limited by stack height. It can't be too tall or I won't buy it. SuperSix 51 is too tall.

[drumjdds]

interesting, I'm always playing around with different stem lengths and angles on my size 51 S3. now I'm thinking perhaps size 49 with a longer stem like you