Specialized's wheel brand Roval has two new wheelsets: the alloy Traverse Fattie and the carbon Traverse SL Fattie, both of which come in 650b and 29in sizes. It’s worth noting that Roval won’t be offering either wheel in 26in. The new wheels are aimed squarely at the booming trail and enduro market, but draw inspiration from the monster rim width used on fat bikes.
Roval engineers admitted there was some initial hesitation about trying cross-over technology from the fat-bike fraternity. After a bit of persuasion from engineer Jason Chamberlain — who inspired the project after getting into fat bikes himself and feeling the benefits of the wide rims — that they finally hit the hills on their trail bikes using the 45mm inner width alloy prototypes, which weren’t exactly featherweight.
“It was a little difficult to swallow as we’d been riding nice light carbon rims,” said Roval’s Joe Buckley. “And right away, yeah, of course this rim is heavy by the nature of what it is [a prototype], but what I was able to ride with the low air pressures — typically I ride on a narrow rim I run 30psi in the back and 28psi in the front and with these I was running them in the low 20s — and the amount of traction and additional control was like, holy crap! This is a miserable wheel to pedal around but the traction is amazing! Right away, we knew there was something to it."
Spoke-hole plugs offer a tubeless set-up without the weight of super-wide tubeless strips
Buckley and his team then began experimenting with various rim widths, looking at the benefits of the wider rim versus the trade off in weight. After studying a variety of options in the lab and through real-world testing, they settled on an inner rim width of 30mm, “which is a good balance between the weight and the amount of traction you’re getting,” Buckley said.
So what are the advantages of a wider rim? A wider rim helps increase tyre volume, which produces a more comfortable feel, as well as increases tyre support allowing the rider to drop tyres pressures for improved traction.
Once rim width was decided the design process could begin.
The wider rim meant few spokes could be used
Traverse SL Fattie — US$1,400 / £TBC
The claimed weights of the new Traverse SL Fattie wheelsets: 1,530g in 650b and 1,570g in 29in. The wider rim and its additional stability enables Roval to reduce the spoke count down to 24 spokes up front and 28 at the rear, compared to the old Traverse SL 29 wheels that used 32 front and rear. As a reminder to those worried about durability, Roval engineers were keen to highlight that the focus was “on durability over weight loss," which is why the rims are reinforced around the spokes.
The new wider or ‘Fattie’ high-end carbon rim uses the same ‘Zero-Bead Hook Technology’ as previous rims and is laced to a DT Swiss 350 rear hub that uses a 54-tooth ratchet, offering 6-degree engagement for rapid pickup, and is compatible with the standard 135mm and 142x12mm rear axles. There’s also Roval’s 142+ option which steps out the hubs flanges (spacing the cassette out an extra 2mm), bolstering rear wheel stiffness by a claimed 10 percent. The 142+ option is only compatible with Specialized frames.
Up front, the hub stays the same as before — just with a lower spoke count — with an alloy body and sealed cartridge bearings and will work with 15mm or 20mm front axles.
A DT Swiss 350 rear hub anchors the wheel
There’s also three different vinyl decal options included if you’re not taken by the stealth carbon look.
On top of that, the Traverse Fattie SL can be run tubeless using Roval’s rim strips or their new Roval Rim Plugs. Fatter rims naturally require a fatter and therefore heavier rim strip in order to run them tubeless. Roval employees say that widening the rim strip out to work with the 30mm rim bumps its weight up to 72g (on the 29in wheel). To get around this, Roval developed rim plugs that snap into each of the spoke holes in the rim bed, creating an air tight seal thanks to o-ring used on each one. This reduces the weight over a wide rim strip by 60g and are included with the carbon Traverse SL Fattie wheels. They’re also provide a more consistent seal which won’t shift around over time, they say. If you chose not to use the rim plugs, the rim strips have also been improved upon to ensure a better seal.
Roval also modified its tubeless valve, which now features a button-head style top that is supposed to work better with flatter rim beds profiles.
Traverse Fattie — US$600 / £TBC
The plan started out with the idea to create a 30mm inner width version of the Traverse SL Fattie in alloy, but after the first test sample arrived, things weren’t quite what Roval had hoped for and the design had to be tweaked.
“We wanted to do 30mm and we designed the extrusion, got the first test samples in and what we found was that it doesn’t translate exactly how like it does in carbon," Buckley said. "Having a standard straight sidewall is nice and light, but the problem was that it wasn’t that ding resistant." So, about 0.5mm materail material was then added to each side of the sidewall.
“The goal was to go totally hook-less, but to get the strength we wanted out of the wheel, we found that it was necessary to add that material at the top," Buckley said, adding that this is still not enough material to be considered a bead hook.
The rear wheel features the new DT Swiss 360 hub, which uses a 3-pawl mechanism rather than the Star Ratchet, but is still compatible with the XD Driver body. Rear axle compatibility covers the usual 135mm and 142x12mm, but unlike their carbon counterparts, there’s no 142+ option here.
Up front, the hub used is the Traverse Fattie is identical to that used in the Traverse SL Fattie, so they’ll work with 15mm and 20mm axles.
Spoke counts are also the same, using 24 spokes up front and 28 at the rear. The weight has been kept to a minimum, with the 650b pair coming in at a claimed 1,690g and the 29in pair coming in at a claimed 1,770g, which is impressive.
Sadly, the rim plugs that are included with the carbon Fatties won’t be available with the alloy wheels, but this could change over time.
