Life from an outsider's perspective…

Hayes V9 rotor, the incredible 9″ disc.

Hayes V9 9 inch disc rotor.This 9 inch beast is the biggest and baddest disc brake rotor out there at the moment. Yes of course it’s “grabbier” than smaller 7″ and 8″ rotors, but it does provide stronger braking no matter what brakes you’re using. It’s a simple upgrade although technically not compatible with many of today’s suspension forks. It only offers a marginal brake power improvement over standard 8″ front discs used for downhill mountainbiking.

The main benefit of the Hayes V9 rotor is the increased cooling capacity. I recently descended some continuous 20% streets, and although the disc gets extremely hot, there is absolutely no detectable loss of brake power due to “brake fade”. Most riders will not notice any difference compared to normal 8″ rotors. If on the other hand, if you regularly ride down the world’s steepest streets, these are well worth the money.

Hayes V9 disc brake 9″ post mount adapterI’ll be honest and admit that when I first got the disc from JensonUSA, I just went straight down the nearest steep street I could find to test out its performance. Since I didn’t bed the pads in properly, I looked down at the front wheel to find this disc was drastically warped within about the first two minutes of use. It was clanging about like an old errant hubcap after a multiple car pileup. The disc managed to get back into shape on it’s own, and I haven’t had any further problems since then. Needless to say, you’re supposed to gradually increase the force you apply to the levers.

After a while, I found the Hayes 9″ disc grabs once during every rotation of the wheel. There is not much I can do to prevent this. The Hayes disc is only slighty warped, but that alone does not normally affect the actual stopping power. This interferes with the ability to brake on loose surfaces and I lost a lot of confidence when applying the front brake only. A better option is the Formula 220mm disc rotor.

6 Responses to “Hayes V9 rotor, the incredible 9″ disc.”

  1. where can i buy this?

  2. JensonUSA appear to no longer be selling them. Try or I recommend the Formula 220mm rotor with the alloy carrier… I’ll write a review of that this evening…

  3. Technically not compatible with a smaller fork…. but what actually happens to the fork if I use this rotor with say a Fox 32?

  4. Well the first thing that will go will be the main fork seals on the stanchion tubes. But other than that, I think you risk physcially damaging the fork legs and disc brake mounts. Simply because bigger discs generate a bigger force on the forks…

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