WTB CZR i30 Wheelset Review: These Carbon Circles Keep on Rollin’

If you’re under the age of 40, there’s a good chance your first mountain bike rolled on rims from Wilderness Trail Bikes (WTB). The California-based company has been designing components since 1982, and their new CZR i30 wheels are a testament to those long seasons of R&D. We tested a set of the $1,600 hoops (available at Performance Bike and other online retailers) under a hardtail and full suspension bike with a few different tire variations. The results came out heavily in WTB’s favor.

WTB CZR i30 wheel specs and construction

Compressing the scale to a total of 1,949g with tubeless tape and valves installed, these are not the lightest or the heaviest 28-spoke carbon wheels on the market, and weight doesn’t appear to be their primary objective. Each of the rims is laced with 28 three-cross spokes, with brass nipples at the far end adding some heft to the build. Brass corrodes slower than alloy and it’s less likely to round off while truing the wheel. It looks like WTB set their phasers to longevity, and the carbon spheres include a lifetime warranty.

WTB made a smart bet with limited models for the CZR i30 wheels. The rims only come in a 29″ diameter, and the hub spacing is boost-only, pairing well with the standards of most modern bike frames. The internal rim width is 30mm which sits nicely with the majority of gravity tires that folks will mount up. Like the carbon rims from Reserve, these have reinforced spoke beds to ensure that none of the nipples pull through under maximum trail pressure. With a top rider weight of 300lb, the force on those nipples could become quite high. I have had zero issues with this wheel build, and all of the components and construction seem spot on.

We asked WTB about the spoke beds specifically and they replied, “The reinforced spoke beds on our CZR i30 rims/wheels allow us to strategically strengthen areas of the rim that experience the greatest forces, while also using less material elsewhere to subsequently save weight where it isn’t needed (in between spoke holes). CZR i30 spoke beds are roughly three times thicker than the thinnest areas of the rim walls. Increasing material thickness specifically around the spoke hole not only greatly increases spoke pull-through strength, but also increases overall vertical compliance through the thinner areas of the rim profile. This strategic buildup of carbon is similar to how the legs (often referred to as the bead area) of our CZR i30 carbon rims are disproportionally thick in order to provide strength during hard rock hits while still allowing the transition area of the legs to quickly thin out into the rest of the rim profile, thereby saving weight. ”

A friend here in Bellingham has been riding the WTB Frequency hubs for more than two years now without needing to service the bearings. They remain smooth spinning, which speaks heaps considering the onslaught of rain and mud our gear sees here. In addition to their long-lasting cartridge bearings, the Frequency hubs use a 6-pawl freehub body that alternates between groups of three pawls at a time for a solid 5° of engagement. While it’s a ways off some hub engagement measurements I’m stoked on just a 5° piece of the pie moving before the power transfers. The engagement is plenty tight for tricky climbs where I need to kick a half-stroke of the cranks between tall rocks, and I’m not left pining for the 0.52° of my other hubs. While near-immediate engagement feels great, this smidge wider angle is by no means problematic.

The CZR i30 wheels came with tubeless tape and valves installed, and all of the tires I mounted have snapped to the shoulders with floor-pump pressure. I have yet to burp a bead on these, leading me to believe that WTB, like many other brands that design rims, have the internal profile and diameter dialed. They manage to achieve that easy and tight tubeless seal without making the tires so tight that they can’t be dismounted in the woods when it’s time to install a tube. Thank you rim designers, one and all!

On the trail with the CZR i30 wheels

Hardtails are to carbon wheels what flat pedals can be for foot technique; demanding. The rigid rear end provides a good amount of feedback, and it can be easier to find the flaws in tire traction and wheel deflection when there’s no shock to hide movements and energy transfer. I started off testing these wheels with my favorite Magic Mary and Big Betty tread combo from Schwalbe since I know well their grip and support characteristics. Those cozy casings felt right at home on the CZR i30 rims. There’s a record skipping here, and the title track is “All Carbon Hoops Are Great Today.” It blares loudly behind most reviews of contemporary carbon wheels, and this set is no exception. I pushed these wheels as hard as my little hardtail can handle, damaging the air spring of a fork in the process, and the WTB wheels remain smooth and true.

On to the full-sus bike they went, and I bet you can guess how this part of the story rolls. The CZR i30 wheels provide all of the best steering stiffness a rider could want alongside a chunder-damping demeanor that matches the best carbon wheels we’ve had the pleasure to pedal between. Carbon can be tuned with precise amounts of impact forgiveness in different directions, and these rims seem to have the compliance variables properly aligned. On the steepest and messiest descents near this part of the Canadian border, this wheelset can hold a line as well as wheels that cost a fair bit more.

The WTB wheel system loads up tension nicely in fast compressions, with a quiet and smooth spring out the other side. From ride one, the spokes and nipples have yet to utter a peep, lacking the familiar “ping” that can accompany wheel builds where the spoke stressing process was skipped. Tension on all 56 spokes feels balanced and the tension meter is happy with the scant amount of variation. To top it off, the rims are as true as the day they were laced, free of any alarming blemishes.

In summation

The all-black colorway on these wheels may not be for everyone, but if you’re okay with your hoops not screaming “yo, I spent more money” the performance is definitely there to reward your purchase. These carbon wheels sit in a moderate weight class, waiting patiently for folks who appreciate the ride feel of carbon above the gram-saving possibilities. If you’re in the carbon circle market and want long-lasting hubs and rims with a lifetime warranty, these are worth a long look.

• Price: $1,600 (pair)
• Available at Performance Bike and other online retailers.