Roval Traverse 38 SL Fattie 650b 148

While there may be a linear relationship between increased tyre size and increased fun, this relationship only holds true when wider tyres are paired with the correct width rims. Having a three-inch tyre mated to a narrow rim makes for a squirmy, poor handling experience, and when you’re on the hunt for additional fun, these characteristics are undesirable. Lucky for you, the new age of traction, stability, and speed has arrived—and its name is the Traverse 38 SL Fattie 650b with a 148 rear.

While our 30-millimeter Traverse SL is already wider than most offerings from others, the benefits of three-inch tyres become more apparent with a proper rim interface. In search for the proper width, our engineers tested various iterations, from 30 to 45 millimetres, to determine where the sweet spot lies. What they ended up with is a 38-millimeter internal rim width that turns the Traverse 38 SL Fatties into descending machines.

A wide internal rim width endows riders with a variety of advantages that are exemplified even more with plus-sized tyres. The extra width allows for more tyre volume, translating into more supple ride qualities, and better support for the tyre, meaning that you'll experience less "burping" when riding tubeless and a drastic increase in traction. After determining the proper rim width for the plus-sized application, we began designing the rim using the same low-weight, high-strength technologies used in the Traverse SL and the Control SL. With this, we started with our Zero Bead Hook design that effectively eliminates the biggest weak spot found in traditional rims, and topped it off by using high-modulus carbon fibre to keep the weight down to a respectable 1650 grams.

Each Traverse 38 SL Fattie is hand-built to our own alloy hubs with DT Swiss Revolution spokes. Inside our hubs, you'll find sealed cartridge bearings all-around, and a quick-engaging 54t DT Swiss star ratchet system in the rear, allowing you to power over rocks and roots without delay. And while machines do a decent job of building wheels, we choose professionally trained humans to build ours, as they catch various flaws that a machine would otherwise miss. You likely noticed that the 24-front/28-rear spoke count seems low for such a burly wheelset, but during testing we discovered that when built with 32 spokes, the wheels were too stiff, resulting in poor ride quality.

To further reduce the overall weight, the wheels also include the Roval tubeless plug system, which sheds an additional 50-grams-per-wheel compared to a rim strip. Finally, with the 110/148 variant, you receive all of the benefits that Boost spacing offers. By increasing the width of the front and rear hub flanges, and in turn, increasing frame and fork clearance and stiffness, you obtain a stiffer, stronger, and more durable system at a minor weight penalty.

If you’re headed into the plus-sized wheel market, pick yourself up a set of Traverse Fattie SL 38 650Bs and notice for yourself that Fatties don’t have to feel fat.

• Rim Type: Carbon clincher, 2Bliss Ready, Zero Bead Hook design

• Rim Material: Carbon fibre

• Rim Width: 38mm internal

• Front Spoke Pattern: Radial/Three-cross (2:1)

• Rear Spoke Pattern: Three-cross (1:1)

• Spoke Count: 24-hole Front, 28-hole Rear

• Spoke Type: DT Swiss Revolution

• Nipple Type: DT Swiss Pro Lock hexagonal

• Front Hub: Alloy body, 15x110mm thru-axle only—15mm end caps included

• Rear Hub: CNC-machined alloy body, high-quality DT 350 internals and 54t quick engagement ratchet system cassette, includes SRAM XX1 11-speed freehub and 148 end caps

• Bearing Type: Sealed cartridge

• Assembly Method: Hand-built

• Every wheel includes tubeless valve stems in order to make tubeless set-up a touch easier.

• Total Wheelset Weight: 1,657g