Curious if anyone has road one of the cannondales and how they compare to each other. Is one of these bike leaps and bounds ahead of each other? I've got the ability to et a six13 pretty cheap but should I hold out for a CAAD or System6?

I have been riding a Caad for years, Love it.. I also just bought a raw finish Six13 in a 54, frame was 1168 grams and the fork was 344. I have it built up to 6350KGs with carbon 50mm rims, Speedplay Ti's and Sram Red. Love it thus far. They say the System Six is stiffest Cannondale going and I think some tests show that to be the case. I think the Six13 is slightly softer ride than a Caad8/9. Good Luck!

I had a 2005 Six-13 (the original, three carbon tube version). It broke and Cannondale replaced it with a System Six. I also added a Caad 9 as a race frame when I broke my older Spec. S-Works Alu. frame.

The Six-13 was awesome. I really liked it. I honestly can't offer any more about it since I broke it five years ago and don't really remember much about it other than I really liked it.

The System Six was even better. It is substantially stiffer in the front end due, I think, to the oversized headtube and fork. It is the best bike I have ever ridden - I like it better than the Evo I test rode a few weeks ago. I have yet to find a bike I like better. If you can find one in good shape, particularly one that has been painted an not the raw alu./carbon version, it is worth it.

The Caad 9, it's ok. It isn't as smooth or as stiff as the System Six despite sharing the same rear triangle. I think the alu. S-Works I had was a superior aluminum frame.

Sadly, my System Six is suffering from severe galvanic corrosion - an issue common on the unpainted Six-13s and System Sixes. It's reached a point that the clear coat is pealing off. My wife is convinced it is no longer safe to ride, though the local rep says it is just cosmetic. Regardless, I don't want to on the bike when I found out it is more than just cosmetic, so I am getting a new bike.

I posed a similar question recently. I currently have a Six13 and enjoy it quite well. As my riding has improved I've been wondering if a stiffer frame would benefit me, but I'm not sure I need it just yet, having only been riding for 2 years. My wife has a CAAD9 in the same frame size, so I took it out a few days ago to give it a try. I couldn't tell a big difference, but perhaps I'm not sensitive enough to notice. I will continue to enjoy my Six13 and think about a System Six or Super Six sometime next year.

I ride all mentioned models in parallel (CAAD 4, CAAD5, Six13, System 6 and Super 6 (HM and standard) all sized in 60.
The CAAD 4 is quite a reliable partner (surprise, surprise). Although with 1" steerer, the fork with alloy steerer allows a sportive kind of riding. It is not really light and the small tube diameters are not quite fashionable, I like and use this rig for the dark and wet seasons of the years.
CAAD 5 is unquestioned a masterpiece. Light, stable and made in a time periode in which C´dale offered really flashy and nice painting options. Not comfy but a real racer with a great geometry.
The Six13 Team, based on the CAAD7 with inserted carbon tube is a very comfy, not to say wobbly, bike. I ride the frame with a Look HSC5 Sl fork, which is quite a decent fork. But it does not help. Compared to all other C´dales: the Six13 is a eyecatcher on shaky legs. Sorry Six13.
The System 13 followed the Six13. And C´dale heard what customers said. This frame is made for heavyweight riders. The headtube with its incredible large diameter is rock solid. As is the fork. The rear end, again from the CAAD7 gives no indication of comfort. This bike is made for sprinters. The Liquigas scheme is my favorite. With regards to the present marketing hype of "aero", this frame is a top looser due to the unmatched tube diameters. I love it.
The Super Six has better designed proportions; the front end tube joint is nice and beefy. Even a size 60 frame looks muscular and not bone thin like steel frames in that size. The ride gives way more comfort in the rear end. Having said this: we all know that good tires, weight-leveled pressure and a Syntace P6 are the incredients for a comfortable ride over a long time.
Nevertheless, c´dale made a huge leap with the SuSi.
BTW: I cannot recognioze ANY difference between the HM and standard frame. Weight? No idea. I ride.
Hope this helps

The older frames, particularly around the CAAD7/8 era are just as light as the CAAD10. The first iteration of the Six13 was not bad either. The late Taiwanese models just come across as cheap and generic, at least IMO.

I have owned CAAD5/7/8/9...with the 9 obviously the best of the four. I was going to get a CAAD10 but I could not pass up this new, 2007 System Six frame for $500. I've ridden the Super Six(2010) and EVO(2012) and I still strongly feel the System Six is the stiffest, most sprint-responsive frame Cannondale ever made:

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