It was with some reluctance that the engineers at Roval began experimenting with fat bike width rims in an attempt to see what benefits – if any – they might be able to harness for their new trail wheelsets. But it didn’t take them long to realise that the wider rims offered more tyre support, increased tyre volume and, with the ability to run lower tyre pressures, more traction. While prototypes started with a whopping 45mm internal width, Roval finally settled on 30mm.
Our carbon Fattie SL wheelset weighed in at an impressive 1,580g (for the 29in version). The rims use Roval’s Zero Bead Hook Technology and come with the option of using Roval’s revised tubeless rim strip or new rim ‘plugs’, which snap into each spoke hole to create a tubeless seal and save a claimed 60g over the rim strip. Even with just the rim plugs in place, setting the tyres up tubeless with just a track pump was never a problem throughout testing.
Roval has reduced the spoke count compared with its previous Traverse SL wheelset, dropping from 32 spokes in each wheel to just 24 front and 28 rear. On steep trails where you’re likely to drop into tight catch berms, you can feel some lateral flex, but it’s minimal and doesn’t affect steering accuracy when threading your way down particularly fast, technical routes. Though the Fattie SLs aren’t quite as stiff as pricier counterparts from the likes of ENVE they’re not that far off, and they’re still a big jump up in stiffness over alloy rims, as well as feeling more taut, sprightly and fast through the turns.
As you’d expect from the 30mm internal rim width, the increased tyre volume does offer that bit more comfort on really rough trails, and we’ve had no problems with tyre support or burping when running pressures a good few psi lower than our standard 25psi front, 28psi rear set-up. We dropped tyre pressures down to 18psi to really test the traction benefits and were seriously impressed with what we could get away with. Push the tyres hard at that sort of pressure and things do get a little squirmy though.
After nearly four hard months of testing, both easily convertible hubs are still spinning smoothly, with no play in the bearings. The rebadged DT Swiss 350 rear hub continues to offer a reassuringly quick pick-up too, with consistent, positive engagement each and every time you put the power down.