# Supersix/Caad 9 sizing re: stack/reach



## PlanetSimon (Sep 6, 2010)

Can someone explain Cannondale`s sizing protocol to me, as researching the stack/reach figures on the geometry chart shows no logical progression across the sizes. For instance, a 44 has the same reach as a 48, a 52 practically the same as a 54 and a 63 the same as a 58 (and less than a 60???) It seems obvious to me that if the seat tube angle changes across the sizes then the change in the top tube length needs to be adjusted to allow for this and not just proportional to the size increase which is how they appear to have done it. Given Cannondale`s years of designing bikes they must know what they`re doing, so am I missing something?

HTTL:Horizontal Top Tube Length, STA: Seat tube Angle, Stack: Stack, Rea: Reach

SIZE 44.0 - 48.0 - 50.0 - 52.0 - 54.0 - 56.0 - 58.0 - 60.0 - 63.0
HTTL 50.0 - 51.5 - 52.5 - 53.5 - 54.5 - 56.0 - 57.5 - 59.0 - 60.0
STA. 76.0 - 74.5 - 74.5 - 74.0 - 73.5 - 73.5 - 73.0 - 72.5 - 72.0
Stac 50.3 - 51.7 - 52.3 - 52.9 - 54.6 - 56.0 - 57.9 - 59.3 - 62.2
Rea. 36.8 - 36.8 - 37.8 - 38.2 - 38.3 - 39.4 - 39.9 - 40.4 - 39.9

PS: apologies for bad formatting,. Figures from Cannondale Geometry charts


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## Cleaner (Jun 19, 2009)

*The stack changes account for the sizing*

The bar center location is affected by the stack so even though 2 frames may have the same reach the location of the bars relative to the saddle will change more than the reach #s from the chart would suggest at face value.

See the picture, it illustrates why changing the stack moves the bars enough between sizes to have some delta that is significant when sizing up. This is the distance from the tip of the saddle to the center of the bars.


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## STARNUT (Jun 19, 2005)

what he said. Plus there is a few other things going on here. First is stack. The 44-48 have the same reach and different stacks same with the 52-54. This is pretty common in italian manufacturers. Go look at Pinarello and Colnago. I think the 4 largest sizes of the C59 from Colnago have the same reach. Made for different people.

Additionally, the chart does not show the caps and cones that both bikes come with for their respective headsets. Most of the CAAD9s and all the Supers come with a 20mm cone thing for the top of the headset. 99% of the Supers I see have that cone on them. So you'll need to add 20mm to the stack and reduce the reach as well to account for negative reach when the bars move up. You can run both frames sans cone (like I do)

Starnut


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