Dirt Rag Magazine

Review: RockShox BoXXer World Cup Keronite

By Matt Kasprzyk

This grey dual-crown fork might look unassuming among the RockShox BoXXer line-up, but there are a few distinct updates and tech features that set it apart from other downhill forks, even within the BoXXer family.

The Lowers

That grey color of the fork’s lowers is a result of a sealing process called Plasma Electrolytic Oxidation. It’s an electrochemical surface conversion treatment that is applied to the magnesium lowers. Maybe it sounds a little like hard anodizing? Well, it kind of is. This specific PEO tech has its roots in the Russian space program and has also been used in the aerospace and automotive industries.

The Keronite PEO process can make the surface of soft metals, like aluminum or magnesium, harder and more wear-resistant, while increasing corrosion resistance without the use of heavy metals or strong acids.

So what’s the big deal? Well, for the same price as the other BoXXer World Cups you can save 30g. In many applications Keronite is used to increase wear resistance. RockShox uses it to reduce weight and eliminate the inconsistencies of paint.

In addition to the lowers, the external adjustments also got makeover for 2011. Everything is tool-free. Trailside adjustments are made easier with repositioned knobs. Independently-adjustable high and low speed compression, and beginning and end of stroke rebound controls are right at your fingertips, well, at least they are when you take your hands off the bar…

On the inside

The BoXXer R2C2 and World Cup models also got some updates on the inside. The Mission Control DH rebound dampener does away with the Floodgate threshold adjustment in favor of a high-flow compression piston to optimize “descent-oriented bump performance.” Basically, this means that the ports in the piston are now larger, for improved oil flow. RockShox’s goal is to have the rebound assembly provide no compression effect of its own.

Rebound and compression are now designed to be totally independent of each other. The air spring and dampening units were also moved lower in the legs—apparently there were a few issues with over-tightened crown bolts creating stiction. The Solo Air assembly controls both positive and negative air pressure and is fed by a high-pressure Schrader valve. The new Schrader valve system eliminates the older O-ring seal, which was prone to wear.

On dirt

Setting up the BoXXer World Cup was fairly simple. There’s a sag guide printed directly on the stanchion in 10, 20, and 30 percent increments. Improved detents make adjustments easier and the RockShox website provides some good starting points for setup with their tuning guides. At 190lbs., I started at the recommended air pressure and have reduced it slightly since then to achieve full travel. I’m currently about 6psi less than what’s recommended. After talking with RockShox, this seems pretty typical.

The setup guides are really just a starting point; your personal settings will reflect your own riding style and terrain. For high-speed compression, I ended up settling on two clicks from the softest setting. (That’s one click softer than recommended.) I was getting too much feedback on small, high-speed bumps, like the braking bumps often found at bike parks. Low-speed compression seemed to be dead-on with what was recommended.

Beginning-stroke rebound is something I’m still playing with. This is how fast the return stroke speed is through the first 40% of travel. A slower beginning-stroke rebound will allow your front wheel to stay on the ground more, but I feel there’s a balance I haven’t quite found, of being able to skip over bumps and absorbing too much. Right now I’m at 10 clicks from slow and RockShox recommends 13. Ending-stroke rebound is how fast the fork returns to full travel after large hits. For the local rockgardens, tabletops, and mid-sized drops I’ve settled on the recommended 13 clicks for my weight and have left it there without any issues.

Final thoughts

In terms of performance, I’m not sure how you could really complain about this fork. It’s one of, if not the, lightest production downhill fork on the market. It’s incredibly tunable to style and terrain, and the Keronite surface treatment might increase durability, but it certainly decreases weight. My opinion is that if this fork doesn’t feel good to you, then you probably don’t have it set up properly. It’s not cheap, but the Keronite version is the same price as the other World Cup models. There’s no up-charge for the fancy Russian space tech, so if you want to save an extra 30g, then I guess you’re getting a gray fork. Maintenance on an air fork will be more than a on coil-sprung model. So if you don’t like to tinker, stick with a coil. RockShox recommends 20-hour service intervals and an overhaul once a year.

Product specs

  • MSRP: $1,700
  • Travel: 200mm
  • Weight: 5.93lbs. w/o crown
  • STeerer: aluminum, 1 1/8”
  • Spring: Solo air
  • External adjustments: beginning and end of stroke rebound, high and low-speed compression, bottom-out control.
  • Disc mount: 74mm post mount
  • Country of origin: Taiwan
  • Online: www.sram.com/rockshox
 

 
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