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Fit For Purpose — Avid XX World Cup Hydraulic Disc Brake

  • By Ben Marchant
  • Published Dec. 14, 2011
  • Updated Oct. 11, 2012 at 4:51 PM EST

SRAM XX was developed as a World Cup level group set to give its premium riders and athletes every advantage when it came to weight, strength and performance. Developed in conjunction with their Pro level Black Box program it resulted in some of the world’s lightest components.

For World Cup cross country racers weight is a big big issue. Riders have been known to ride with three instead of six bolts securing their disc rotor (this editor recommends not trying this at home) in the pursuit of saving those few precious grams.

The XX caliper dropped the weight of the CPS but World Cup riders want more weight shaved. Photo courtesy of SRAM

Every aspect of weight saving has been addressed. The Avid standard Caliper Positioning System (CPS) (the cup and ball washers which allow for fine tuning of the caliper position) do not feature at XX level, which isn’t so bad given that most brake manufacturers don’t bother with them either.

The TaperBore system has been tweaked (more on this later) and every aspect of weight saving has been utilized, including a carbon fiber lever blade and magnesium calipers.

However, for the World Cup racers, even that was not enough. Take a 288 gram Avid XX brake and make it lighter? Really?

First up, take away the pad adjustment. You don’t need it if you have a mechanic in the pits fettling your gear for you after every ride. You have now saved a whopping 11 grams. Next use titanium bolts where possible such as on the matchmaker clamps. The full system weighs in at a svelte 277 grams.

For 2012 Avid tweaked the technology in both its XX level brakes. The company’s TaperBore system (the fluid in the lever is compressed into a tube that tapers as you get into the stroke) was refined to allow for better modulation through the lever stroke. You want to scrub speed quickly without locking out the system and going into a skid at this level.

This is really noticeable on the trail and feels very tuned. The brake is never squishy or soft under braking; rather you are aware of having more power available if necessary. I felt like I was able to hold my speed better as I was braking more precisely. This is a big plus.

On the flip side there is no brake fluid reservoir on the lever, meaning that it is a lengthy procedure to bleed them, something we did have to do. Again this is fine if you are a World Cup racer and have a mechanic on standby but in the real world it is a bit of a pain requiring syringes etc.

The levers are attractive, but the lack of a brake fluid reservoir on the lever makes bleeding difficult. Photo courtesy of SRAM

However the bigger problem concerns the lack of pad adjustment. This shouldn’t be a big thing yet. But as the pads wear, the lever will pull closer and closer to the bar. Ideally you need to add brake fluid. Bleeding the system is fine once you are confident in your abilities. Avid put out a really good video that shows you how to do it, but this in itself shows you that it is not a simple procedure. I found myself lamenting the loss of brake fluid reservoirs.

It is great in the looks department — a nice stealthy black as opposed to the standard XX grey. The lever feel is really natural and doesn’t feel plastic like some carbon levers can. Reach adjustment is via an Allen key under the lever and is fine. The caliper is nice, with great power transfer. Pads are now top-loading on all Avid systems, making them easier to replace. That being said, our set endured a fall of abuse like champions, in totally mixed conditions and terrain.

How do they compare to the competition? Well, brake feel is a highly individualistic thing, but don’t interpret that statement as a cop out.

This editor prefers brakes from a number of manufacturers for different reasons. Shimano brakes are so bomb-proof and easily serviceable. Magura’s new MT range have awesome power, low weight and a great feel and Hayes brakes are really getting their act together with their new Prime, while Hope and Formula have downhill strength power at XC weight.

So where does SRAM XX fit in? It is definitely in the ballpark, certainly in terms of weight, and it has one of the best lever feels and modulation. “Fit for purpose” is how I would describe them – a really great choice for the serious cross country racer.

Overall this is an excellent brake, but I wonder if it is really necessary for anyone but a top level cross country racer, and SRAM would probably agree. If you don’t fit that description, check out the regular XX brakes, or opt for the 50 gram heavier X0 series, which is very similar. You will be glad of the pad adjustment and probably not too worried about the extra weight.

FILED UNDER: Bikes and Tech / MTB TAGS: /

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