In Review: Crankbrothers Zinc 3 Tubeless-Friendly Rims Provide Cure for Burps and Blowouts

Crankbrothers has made a name for itself designing innovative products, from its revolutionary Eggbeater pedals to its various lines of compact, trail-ready multi-tools. This philosophy is also applied when building wheels that do not have the traditional J-bend spokes and drilled rims.

Crankbrothers' new wheelset is the Zinc 3, which is its first wheel targeted specifically to the cyclocross and gravel crowd. We first caught a glimpse of the Zinc 3 at the Sea Otter Classic earlier this year. Using Crankbrothers wheels for cyclocross and gravel is not new for us; we have previously had good results using the Cobalt 3 wheels for ’cross and gravel riding.

Crankbrothers Zinc 3 cyclocross/gravel wheels are disc only, tubeless ready, and eye catching. © Cyclocross Magazine

Crankbrothers touts lower rotating inertia for the Zinc 3 due to more of the wheels’ weight being closer to the hub. Without a published rim weight, it is hard to verify, but we would believe compared to a wheel of similar weight, it may have some slight advantages. However, the nipples are much longer than a traditional nipple and the rim’s extensions that host the spoke heads require additional material and weight, so we are guessing the acceleration benefits are minimal.

Crankbrothers touts lower inertia and faster acceleration due to more of the Zinc 3 weight being closer to the hub. Without seeing component weights, it is hard to verify. At 1710g, they are not weight weenie champs but so far have proven reliable. © Cyclocross Magazine

Our initial impression is the Zinc 3 is an attractive cyclocross or gravel wheel because of its features and not its ability to fulfill customers' gram-shedding dreams. The wheelset weighs in at an actual weight of 1708g (list weight: 1645g), so the wheels are not going to be pound-shedding hoops for most cyclocross and gravel enthusiasts. The true attractions of the Zinc 3 are the tubeless-friendly rim, unique look and hopefully, a strong, reliable wheel.

While we can’t yet speak to the Zinc 3’s long-term reliability, we can comment on the rim. Anyone who has ever dealt with mysterious tubeless leaks ultimately traced to crumpled or torn tubeless tape can appreciate the Zinc 3’s sealed rim design. The sole hole in the rim is for the tubeless Presta valve. In our past experience with the Cobalt 3 wheels, this design approach has proven to contribute to tubeless reliability.

The 21mm wide rim (internal) sealed rim has just one hole for the valve, and does not require tubeless tape. Crankbrothers Zinc 3 cyclocross/gravel wheels. © Cyclocross Magazine

Avoiding torn or crumpled rim tape is a nice long-term benefit, but avoiding burps and blowouts is a more important everyday concern, especially at the low pressures used in cyclocross racing. Thankfully, the Zinc 3 rim’s wide shoulders and narrow center channel offer a reliable platform for tubeless tire beads. Even during hard cornering or awkward landings, the tire beads stay in place and avoid the dreaded burp of air that signal an unfortunate trip to the pits.

The wide bead shoulder and sealed rim have made Crankbrothers' rims some of the most reliable tubeless rims we've used. Crankbrothers Zinc 3 cyclocross/gravel wheels. © Cyclocross Magazine

The 21mm internal rim width is a moderate width compared to most cyclocross and gravel tires, and we are tempted to call it a tad narrow for 40mm gravel tires when compared to other wheels we have reviewed. Whether used for ’cross or gravel, the width avoids squeezing the tires into an extreme light bulb shape that is conducive to squirming in corners at low pressures.

If gravel riders are drawn to the Crankbrothers wheels but concerned about the 21mm width, they may want to take a second look at the Cobalt 3 wheelset. The Cobalt 3 has an internal width of 23mm and is 90g heavier, but riders may be interested in accepting the extra weight for a wider rim.

The Zinc 3 is set up for a 15mm thru axle in the front and a 142x12mm thru axle in the rear, and both come with caps to make them compatible with quick release skewers. They are set up for International Standard six-bolt disc rotors.

Notably missing at this time is a 12mm thru axle option up front, which will leave a growing number of cyclocross, gravel and road disc users ironically out in the cold (given zinc's touted cold-fighting ability).

Crankbrothers Zinc 3 cyclocross/gravel rear wheels come with 142x12 thru and 10mm quick release options. © Cyclocross Magazine

Crankbrothers uses its twinpair spoke technology on the Zinc 3 wheels. The spokes are straight-pull steel spokes paired on opposite sides of the wheel. We have had good experience with the reliability of Crankbrothers' recent wheel models, but the proprietary spokes may be difficult to find at local bike shops. This should be a consideration if your gravel adventures lean towards multi-day bikepacking adventures in rural areas in the U.S. or abroad, and you will definitely want to pick up a few spares before you hit the road.

Crankbrothers Zinc 3 cyclocross/gravel wheels use twinpair spokes of a single length. © Cyclocross Magazine

One upshot of the unique design is there is only one spoke length you will need to purchase for your gravel adventure. And if you need to replace a spoke or nipple, the Zinc 3 is designed so spokes can be replaced without having to remove the tire and go through the sometimes messy and tedious process of re-seating the tubeless tires.

Crankbrothers Zinc 3 cyclocross/gravel wheels feature a unique flange for true straight-pull spokes. © Cyclocross Magazine

Our impression of the Zinc 3 is it is an attractive wheelset not for weight savings, but for tubeless reliability paired with a unique look and a relatively stiff ride. For those riders who want to have a unique-looking ride out on the cyclocross course, the Zinc 3 wheels provide a sleek look along with the reliable, problem-free tubeless rim.

Stay tuned for impressions of how the Zinc 3 wheelset performs as we continue to test it during off-road adventures.

Crankbrothers Zinc 3 Alloy Wheelset Specs:

Price: $750
Rim: 6061 aluminum alloy, 21mm internal/25.5mm external width, tubeless-ready, disc only
Hub: Crankbrothers three-pawl, 21T hub, HG-splined alloy freehub, XD driver compatible for 10-42 rear cassette
Axles: 15mm front TA, 142x12mm rear TA, end caps for quick release compatibility included
Spokes: 24 paired spokes, CB twinpair stainless steel straight pull
Weight: 1708g (actual), 772g (actual) front, 936g (actual) rear, 1645g (list)
More Info: crankbrothers.com

Photo Gallery: Crankbrothers Zinc 3 Alloy Wheelset