Though we've come to associate it with traditionalism and a staid, stick-with-what-works design ethos over the past decade, the last year has proven Mavic to be quite iconoclastic. The Crossmax Pro Carbon 29in Wheelset embodies this new boldness well, and while it's tempting to characterize it as a sharp departure from the brand's norms, the wheelset is actually perfectly in line with what we expect from Mavic: stiff, lightweight, and—most importantly—reliable. It represents the adoption of two major pieces of relatively new technology: Boost hubs and full-carbon rim construction. When combined, these two developments add a bit of riotous French stiffness to your wagon-wheeled rites of spring on the trail.
For those of you who just did a double take at seeing "new" and "carbon" in the same sentence, let us explain. The new technologies that induced Mavic to go full-carbon include things like hookless beads and the ability to encircle the tire bed in layers of uncut, uninterrupted carbon fiber. Both design features increase the wheel's ability to take hits without folding, and both actually are relatively recent developments. The hookless bead increases strength by eliminating the tiny, fracture-prone shelf of a bead hook; the uncut tire bed does so by eliminating the structural compromises of rims that are drilled for spoke holes. When combined with meticulous lay-up schedules and precise resin impregnation, these construction features give the wheels a reliability on par with Mavic's alloy rims.
The lay-up itself targets radial flex (read: squishy cushion for unruly runs) in order to balance the inherent lateral stiffness of carbon with the forgiving vertical compliance of low-profile alloy rims. The lay-up benefits aggressive riders because it helps maintain contact with lumpy terrain by absorbing impact through engineered flex, bouncing less, and keeping tires glued to the dirt. Boost spacing goes even further down this rabbit hole, spreading the flanges wider to improve the spoke bracing angle and add yet more drive stiffness to the already stiff wheel system—all without compromising the rims' propensity to dissipate shock.
That focus on traction, stiffness, and comfort is obviously well-suited to a tubeless setup, and Mavic's UST design—first developed in the mid-90s—returns with some appropriately impressive developments. The most transformative of these is the lack of a bead hook. In addition to handling bottom-outs with stoic aplomb, the XA Pro Carbon's hookless rim actually holds the tire more securely and reduces blow-offs (while you've got the wheels hooked up to a compressor) and burps (while you're getting sick).
The rim owes these properties to two features not included in rims with bead hooks: a more pronounced central channel and a pair of bead locks, not hooks. These two additions more effectively divide the duties of traditional bead hooks. The central channel centers the tire and helps it seat while inflating, and the bead locks keep the tire bead in place so it doesn't unseat during hard cornering at low PSI. We should note here that tubeless-specific tires are, among other things, less prone to bead stretching, so we recommend sticking to them with these rims.
The rims' ability to damp bumps is further enhanced by the two-cross lacing spoke lacing pattern, which does sacrifice a small amount of lateral or drive stiffness compared to radial spokes, but it also increases that bump compliance, requires less baby-sitting without risking spoke failure, and (most importantly) better handles the torsional load transferred from hub to rim while stopping with disc brakes.
As with its road line, Mavic demonstrates some XC-appropriate restraint with rim width, sticking to a tire-to-rim ratio that makes sense for practical applications rather than scoring on-paper points in the rim-width arms race. A bit of lateral fold in the tire actually benefits cornering, so the vertical side walls of the latest high-volume rims aren't necessarily the best solution for flowy handling. Instead of the 30mm+ rims we're seeing, Mavic opts for a more appropriate external width of 28mm, which is better suited to the included 2.25in Pulse Pro tires. Wider rims risk migrating the tire's shoulder knobs onto the center rolling strip and exposing the side walls to the trail furniture that the shoulders are meant to protect the casing from, but the Crossmax Pro keeps knobs and compounds where they're supposed to be.
The Pulse Pro tread's specialization is further boosted by Mavic's X-Mix dual compound, which features a slightly harder center strip and a slightly tackier shoulder strip for faster straights and more confident cornering. Finally, and despite all the radical changes to the rim, Mavic sticks with the same ITS-4 freehub design. With two sets of alternating pawls, the design limits engagement to XX degrees, providing a bit more bounce while popping over rocky cruxes or struggling across that last root at the top of a roller.
- Cross country wheels that reveal Mavic's inner innovator
- Carbon rim with engineered flex for cushion and traction
- Rim width lets mid-sized tires sit perfectly for flowy handling
- Hookless bead burps less and makes tire installation easier
- Boost axles improve spoke bracing angle for yet more drive stiffness
- Freehub with two pairs of offset pawls for fast engagement
- Two-cross spoke lacing stiffens torsionally but gives radially
- Dual compound tires blend confident handling with speed in straights
- Q & A
Good Design. User Beware of Assembly.
- Familiarity: I've put it through the wringer
What you should know:
1. The Good. I've put a couple hundred hard miles on these wheels. These replaced SRAM ROAM 40s. As expected carbon hoops accelerate faster, they track truer and interestingly the tire performs the same as they did on the old wheels but at about 2-3 psi lower. Overall the design is as advertised. If this was all, I'd have given these 4 maybe 5 stars, but;
2. The Bad. Both hub bearings loosened up noticeably within the first 50 miles. In itself, annoying but not a big deal. Then I had a Mavic dealer local shop check my work. Turns out the rear hub was assembled with zero lubricants in addition to not tightened. Backcountry has no dealer network. You are on your own for work you'd otherwise simply have your local shop address for a defect in assembly like this. This is pretty shit for a wheel set this expensive.
Other Notes to Know:
1. The warranty extends to 3 years if you register. Good.
2. The Mavic tires they promote as included take over a month to get to you. I had to call to make it happen finally. They're only 2.25s. Bad.