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KCNC Razor disc brake rotor review

KCNC Razor disc brake rotor review

A Shimano 180mm 6-bolt disc rotor weighs 138g. A same size KCNC Raptor rotor is just 94g. Fit a pair of KCNC rotors and you’re looking at a big weight saving on your bike without any loss of performance. Yet aside from the clear weight saving, performance is clearly key to such a product. In this respect the KCNC Razor rotors performed every bit as well as the Shimano rotors they replaced.

Ok, so disc rotors might seem like the last place you’d want to save weight, but if you’ve already shed as much as you can from every other component on your bike, then these lightweight aftermarket rotors are a nice way to finish off your bike.

Maybe you have a spare pair of wheels and you want to be able to easily swap from set to set (you might want a designated race set for example)? Or you’ve bent or broken a rotor and need a replacement? These are inexpensive and will fulfil such a need. We’ve paired ours with the lightest wheel and tyre combination we have for racing duties, where every bit of weight matters. Even if it’s only a placebo effect…it works.

Just 94g for a 180mm rotor and in a vital place on the bike, the KCNCs are perfect for weight-shavers.

We also think they look better than many stock disc rotors as well, with the small triangular cutouts giving a very smart look to the wheels.

They’re available in all common sizes, 140, 160, 180 and 203mm, have a 6-bolt drilling and are made from steel – claimed as “the lightest steel discs available”. We haven’t given them the ‘piling into a flying rock’ test, which presumably they would come away from in a worse state than beefier options, but if you’re buying a product to reduce the weight of your cross country racing machine then you probably won’t be all-too-bothered by that.


Lighter than stock disc rotors with no drop in performance.


Light weight


Less robust that a standard disc

Price: from £18.99
More information: Clee Cycles

What KCNC says:

  1. High grade 410 stainless steel (specifically for brake disk use)
  2. Double ground for superior flatness
  3. Heat-treated to 42HRC
  1. toper

    you’re not saving half a pound in weight!
    1lb = 455grams and you save 88grams

    1. James McKnight

      Editor’s clearly got Christmas syndrome… Thanks toper.

  2. Dan

    No loss in performance? I beg to differ. I bought these a few months back because I am a weight weenie. I have since given them away because they simply just did not work as well as the stock Shimano rotors. As gorgeous as the Razors are…this is not the place to worry about a few grams!

  3. David French

    “claimed as “the lightest steel discs available”.


  4. paulhaysom

    David, those are clearly carbon discs – of course they’re going to be lighter than steel!

  5. Sparkyspice

    Avid have added more metal to their latest G3 clean sweep rotors in response to customers who were having them warp on Alpine descents. Therefore I can’t help but think that a “large boned biker” like me would turn these into something resembling a popadum on a long descent…

  6. James Russell

    Hope Floaters all the way for me!!:)

  7. Shane

    I have had them on for 10 days, about 80 mtb miles, including a 25 mtb mile race.
    Initially no power, they improved a lot after 40 miles, but mine are still very weak. The picture above shows the 180mm rotor with the pad wearing at the top and bottom of the rotor. On the 160mm my pads are not that tall so I loose about 1mm at the top and bottom of the rotor which translate into a loss of breaking power.

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