Want to shed weight from your rig? Looking for faster wheels for cyclocross or gravel racing? Hoping to add some volume to your gravel tires? WTB aims to be the answer to your desires this fall with its re-entry into the wheel market. Read on for our review.
Wilderness Trail Bikes, or WTB, known for its tires and saddles, is back in the complete wheelset business after an exit from the segment a decade ago. The newest CZR carbon wheelset is now available in two versions, the i23 for gravel and the i30 for 29” mountain bikes. They differ in the dimensions, stoutness of the carbon rim, spoke count, spoke type, and internal hub specifications.
WTB CZR i23 with ‘fast’ 37 mm WTB Riddler mounted. © C.Lee/Cyclocross Magazine
At least as remarkable as the wheels themselves is WTB’s Ride With Confidence Guarantee. The WTB Ride With Confidence Guarantee is a free replacement for CZR rims and wheels to the original owner if they are broken while riding. That would include smacking your wheel on a buried rock at speed as I’ve done to more than one carbon rim.
We have been rolling on the CZR i23 wheelset for the past 6 weeks, even before public release. According to WTB: “C arbon thickness was fine-tuned throughout the CZR i23 rim to reduce weight, improve vertical compliance, reduce rider fatigue and increase overall comfort.” We cannot say anything about the actual layup but will report that the overall wheelset is quite light, with weight exactly as advertised. WTB advertises wheel weight with tape and valve stems in place. For comparison to competing products, the approximate calculation of a valve stem and typical tubeless tape is 15 grams per wheel. WTB adds a rigid nylon rim strip under the tape (called Solid Strip by WTB) to keep the tape from stretching into the spoke holes and prevent tape punctures that would break the airtight seal in the event of spoke failure. The front weighs 623 grams for our review sample, and the rear 771 grams with the tape and valve stems installed. It is a 1394 gram wheelset, 1364 grams without the tape and valves for a rough comparison to competitive wheelsets. If you remove the nylon Solid Strip, that would make the wheels weigh a few grams lighter still.
The Build
The CZR i23 rim is 23mm wide internally, with a 24mm depth. Its profile is asymmetric to offset the reinforced spoke holes, reducing the dish of the complete wheel. The CZR i23 rim is available separately and WTB advertises a rim weight of 331 grams, which is indeed quite light. Each CZR i23 wheel has 24 j-bend bladed Pillar spokes laced 2X to the proprietary WTB Frequency hubs with external nipples. Frequency hubs have a choice of SRAM XDr or Shimano HG driver body, center lock or 6 bolt rotor mounting, 24 or 28 spokes, but are only available with 12mm through axle, 100mm front, and 142mm rear. The driver has 6 pawls with 3 engaged at any time offering 5 degrees of engagement. The pawl springs in the hub of the CZR i23 wheel are the lighter of the two options. This makes the hub quieter with lower friction than the heavier pawl springs. The heavier spring option comes with the mountain bike-oriented CZR i30 wheel, but can be purchased from WTB for installation by a trained mechanic into the i23 hub. The WTB CZR i23 wheels are built by hand in San Rafael, California. I checked spoke tension which is specified by WTB to be maximally 110-120 kgf. Indeed the dished side (drive side on the rear, rotor side on the front) is consistently just short of 120 kgf all the way around.
The WTB CZR i23 rim has hookless sidewalls, an internal width of 23mm and comes pre-taped for tubeless tires. © C.Lee/Cyclocross Magazine
The WTB CZR i23 rim has an internal width of 23mm and comes pre-taped for tubeless with the valves already installed. The advertised wheel weight includes the tape and valve stem. © C.Lee/Cyclocross Magazine
Our review set of CZR i23 wheels has center lock Frequency hubs with a Shimano HG 11 speed driver and 24 spokes front and rear. The wheels are priced separately at $750 front, $850 rear. The CZR i23 rim can also be purchased separately for $570 if you want to build your wheels around different hubs.
WTB CZR i23 24 spoke carbon rim gravel wheel. © C.Lee/Cyclocross Magazine
I am impressed that the purpose-designed CZR i23 gravel wheelset is so light considering the construction with steel spokes and standard-looking hubs for a price less than 2 grand. The Ride With Confidence Guarantee gave me the confidence to think of mounting cyclocross tires to the rims. With a 29.3mm outside width, I decided to not go too narrow and used a 37mm WTB Riddler, to begin with. The tire-to-rim compatibility met expectations with relatively easy mounting and sealing. The Riddler 37 is a 450-gram tire with a 93mm bead to bead dimension. It is 38.3mm wide when on the CZR i23 and inflated to 30 psi. It offers good rim protection for mild gravel and even some rock chunks if you’re not going too fast and have judiciously chosen tire pressure for your body weight.
WTB Frequency hub with 5 degrees of engagement and a choice of pawl spring tension. © C.Lee/Cyclocross Magazine
The rider weight limit for the WTB CZR i23 is 265 pounds and at 155 pounds, I am well below that. Test rides were on a variety of pavement, fire roads, and single-track trails with a mix of conditions including rocks, roots, ruts, and hardpack. I was lucky not to have any sharp strikes, though the tires bottomed out to the rim on many occasions. The Riddlers had front and rear tire pressure between 25 and 30 psi depending on conditions. The tubeless reliability of a WTB tire to WTB rim was perfect with easy mounting and no burbs during the review period. Based on historic experience with WTB designed rims, I do not expect any compatibility problems with the tubeless tires available today. In one low-speed incident, the front wheel hooked a branch and flipped me into a face plant. My body received more damage than the CZR i23 that only had a bent spoke near the nipple. The wheel stayed completely true, and the rim was not outwardly damaged at the spoke hole.
This carbon rim with similar dimensions to the WTB CZR i23 was the victim of a high-speed (30 mph) rock strike. The rim is 30 mm external width with a 40cm tire mounted run at 23 psi. If this was a WTB CZR i23, it’d be covered by the Ride With Confidence Guarantee. © C.Lee/Cyclocross Magazine
The relatively low profile of the i23 rim and standard spoke lacing pattern may add to ride comfort from the wheels, but the metrics are hard to measure for a tensioned wheel. In the field, tires have more impact on comfort and handling, but longer spokes and less vertical rim stiffness inherent from a lower profile rim add up to some compliance from the wheel itself. All that said, compared to competing wheels, the WTB CZR i23 is no stiffer or flaccid than average. With hard cornering, tested on the road with more tire pressure, and off-road in more typical ‘cross and trail conditions, they don’t waver. They do not have the remarkable lateral stiffness of the Industry Nine UL 240 TRA reviewed a couple of years ago, but neither do they reveal any undue lateral flex that would adversely affect steering or bike handling. A low profile certainly makes riding in a strong crosswind more manageable.
Note the reinforced spoke holes on the WTB CZR i23 rim. © C.Lee/Cyclocross Magazine
WTB Frequency hubs have proven durability so far, though total mileage is still in the hundreds of miles, not thousands. The hubs run smoothly without bearing play or strange noises. Engagement is solid and 5 degrees is plenty close for almost every situation a gravel or ‘cross bike encounters. The hub body has some teeth marks, but nothing extraordinary. The wheels have remained round and true throughout the review period and spoke tension remains unchanged.
The WTB CZR i23 with a WTB Riddler 37 mounted. © C.Lee/Cyclocross Magazine
The Verdict
I’m a fairly light rider and appreciate light wheels. The sub-1400 gram WTB CZR i23 is considered light in the gravel and ‘cross-category. They accelerate and corner well and have proven durable in all the conditions I ride, which are considered under-biking to some. Perhaps WTB expects the wheels to be ridden hard and the WTB Ride With Confidence Guarantee encourages it.
Two things to consider if you want to use the designed-for-gravel CZR i23 for cyclocross:
- The tire may mount wider than labeled. If racing a UCI category, be sure to check if the mounted tire meets the criteria for your category.
- A 33mm tire will offer little rim protection if the course has hard features. The Ride With Confidence Guarantee may offer confidence, but you may still not complete your lap if you have a catastrophic rim strike.
For a gravel event where you may choose a larger tire, the CZR i23 is a great lightweight option. The WTB Ride WIth Confidence Guarantee backs up the sturdy build to make the CZR i23 wheels a great performance value for $1600 since your race wheels can be your everyday wheels.
WTB CZR i23 has spoke hole reinforcements and holes drilled off-center to reduce wheel dish. © C.Lee/Cyclocross Magazine
WTB CZR i23 carbon gravel wheelset specs:
Price: front: $750, rear: $850, pair:$1600
Weight: 1,394g (actual with tape and valve stems); front: 623g, rear: 771g
Rim Weight: 331g (claimed)
Rim: WTB i23 tubeless carbon rim: 23mm inside width, hookless
Rim Width: 23mm internal
Rim Depth: 24mm
Hubs: WTB Frequency, aluminum, 12mm X 100mm front, 12mm X 142mm rear Center Lock, 6 pawls in 2 phases, 5 deg engagement
Freehub: Shimano/SRAM 11-speed, XD-R compatible
Spokes: 24 Pillar SS flat spokes, rear 2X. Front 24 X 2
More info: wtb.com
Stay tuned for more tech in the upcoming weeks.
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