I've been meaning to post this topic for awhile but am finally getting around to it. I have a 58cm SystemSix (in the beautiful silver/black colorscheme) and for awhile I was running some HED C2 rims laced to BHS hubs. With these wide rims, my 23mm GP4000s were measuring out closer to 26mm which was awesome and gave a great ride BUT there was literally a mm tops between the tire and Sram Red (silver) brakes and road debris was getting caught between them. Who knows what would've happened if my wheel went out of true or I broke a spoke! I've tried to search WW and all over the internet in general and essentially have 2 questions.

Do the Sram brakes have especially little clearance and are there brakes that would have greater clearance or is this a Cannondale geometry issue? I've read about Shimano brakes having a little more clearance but I wouldn't be able to run them due to clearance issues.

And my second question for anyone that has run a SystemSix, what were the largest tires you could fit in your frame? I love the stiffness of it but this has me discouraged and thinking about getting a new frame if I'm stuck to running 23 or barely fitting 25's on a standard width rim. Thanks guys for the help!

I'm interested in this also- I was looking at some Hed Stinger 9's, but I chickened out due to the width.



(I've cleaned the bike since I took this photo)

I am very tight on clearance on the rear brake bridge, it is not a caliper issue. My frame will not take a 25 mm tire on a narrow mavic rim.

I'm running a 56cm and I can fit a 23mm tire.. anything more i have issues with seattube, tire clearance... very short stays on my frame

Since the System uses a CAAD 9 rear triangle which I believe has had consistent geometry, and I have a CAAD 5, I can tell you that I tried a 28mm tire on it with no problem. Lots of clearance with Campy brakes. I think it's your brakes causing the problem.

Unless I'm wrong about the geometry of course in which case this is no help.

edit: went to check and from what I can tell from the geo charts and my CAAD there is no difference up to the present.

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dangerous curves ahead

I run 25mm GP 4000s on HED C2 rims (Ardennes) on my System Six with no problems. I have DA 7800 brakes. Hope this helps.

My concern is that the HED Stinger 9 is ~28mm wide, and the distance between the stays is just under 38mm, is ~5mm per side enough, or will I end up with the rim rubbing on the chainstays under heavy load?

My current 808 doesn't, but it's pre-Firecrest, so a lot narrower.

poster's question relates to the height of the brake bridge on the seat stays. Given that the System Six has a fabricated rear end, it is possible to have variations in the location of the brake bridge in relation to the drop out. As I noted, on my size 60, the brake bridge will rub a 25 mm tire. Perhaps a change to a different caliper would help marginally, but on my DA 7800, center bolt is awfully close to the tread of a 23mm tire.

I'm surprised that Cannondale would have this much variation - but obviously they do. My CAAD has more than 5mm clearance to the seatstay and bridge, and 4mm with the brake installed. Also 4mm to the FD clamp on the seat tube.

All pictures with a 28mm Conti Gatorskin.

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dangerous curves ahead

25c Gatorskin, ~5mm clearance to the brake bridge:

Thank you everyone for sharing your experiences. I just don't think this is the right frame for my purposes so it's up for sale in the classifieds

i've seen this bike in person--it's in fantastic shape. someone's going to get a really great deal!

where?

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dangerous curves ahead