Utah based Mercury Wheels apparently is looking to shake up the carbon mountain bike wheel market with some innovative new material tech. Under the vague name of Fiber-X, Mercury claims this new composite material going into their upcoming X-Series trail wheels offers twice the tensile strength of hi-mod carbon, while able to damp major impacts to build a more durable mountain bike wheel.

Mercury X-Series, Fiber-X reinforced carbon MTB wheels

For now, all we really know about the new X-Series wheels is some marketing jargon, plus what we can infer from a few photos we have gotten ahold of (and this teaser video they just sent.)

Mercury has designed these X-1 enduro wheels with a unique trapezoidal rim profile (straight sides, straight top) designed to transfer trail buzz and big impacts into the new, more elastic Fiber-X material where energy can be dissipated. The Fiber-X ‘stuff’ is that prominent silver stripe down the middle of the rim. The idea seems to be that the new fibers allow the rim to take strong successive impact in the same are without compromising wheel strength/integrity.

Mercury X-Series, Fiber-X reinforced carbon MTB wheels

With a claimed wheelset weight of 1670g in 27.5″, these X-1s have a 30mm internal (38mm external) width for aggressive trail riding.

All of the X-Series rims are said to share this general rim configuration, with 27.5 & 29″ rims in development, and internal rim widths ranging from 25-40mm to cover everything from XC to gravity. All of the wheels are set to use hookless, tubeless beads, offset rim beds & embossed graphics. The wheels will also going to be laced to a new Mercury Axis straight pull hubset, featuring fast 3.5° engagement via multi-step pawls.

Mercury X-Series, Fiber-X reinforced carbon MTB wheels

We expect to get the full lowdown on the new rim tech, plus the new hubs in about a week’s time. Keep an eye out…



  1. If the rims are any more elastic than a typical lightweight rim, it’s likely to cause premature spoke fatigue. The same thing happens with those Notubes CB7 rims. There’s a limit to the comfort that can be reliably offered by rim deformation or deflection, and eventually the wheels just aren’t very durable long-term. When spoke tension fluctuates wildly, spokes break. If you can accept replacing spokes more often, it’s perhaps a solution.

    These rim designs are ignoring many years of trial and error, if they think “because carbon/aramid/cloth/fiber” fixes the spoke issue. For racing, fine, do whatever you want, since any advantage helps.

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