Ibis

941 Carbon Fiber 29in Boost Wheelset - DT Swiss 350 Rear Hub

When the carbon ship first landed on the 29er dock, we figured our problems were solved. All the benefits of wagon wheels' fast angle of attack with the floppy nonsense of huge diameters made from alloy. Then Ibis made the wide 941 rims, which boosted stiffness even more. And now, with the advent of the 941 Carbon Fiber 29in Wheelset and its DT Swiss 350 Rear hub, Ibis literally Boosts the 29er wheel game to yet loftier heights of stiffness. Elsewhere, we've referred to the standard Ibis 941 as a monster. Extending that metaphor to include the Boost model would make this the king of beasts.

By now, you know the story of Boost axle spacing: adding 10mm up front and 6mm out back to improve the spokes' bracing angles and make a net gain in tracking consistency and power transfer. The 941 rims' generous widths produce a similar stiffening effect, but that dimension's benefits extend to the tires. The rims' 35mm internal width means the tire beads can sit fatter with side walls that are more vertically oriented, increasing air volume capacity and allow tire pressure to be reduced by a claimed four to six PSI, on average. Essentially, 2.2in tires can widen to a volume akin to 2.3 or even 2.4in tires without incurring the associated penalty in rotational mass.

Lower pressure and fatter tires net greater traction and handling because the tire is able to roll "through" obstacles rather than bouncing across them, so it maintains more contact with the trail. Airborne tires can't grip to transfer power or hold lines in corners, so more trail contact means faster, more confident rides. Wider rims also translate to a wider tire footprint, further boosting traction and increasing stability.

Now, take a closer look at all-mountain wheels these days and you'll find internal rim widths from 21-26mm. Ibis takes that average and gives it an "F." Witness the 941's gigantic 35mm. That is tremendous stability. That is traction for days. And the use of carbon keeps the rim weights down to a claimed 490g per hoop, totaling 1770g for the set. Most of us have accepted that netting the advantages of wide rims and mid-sized tires entails an unofortunate weight gain, but Ibis casts that thinking aside. And, since it comes from the company that raised legendary all-mountain machines like the Mojo and the Ripley, you know durability is a given.

Ibis also tested the gravy out of the best competitors' rims for comparison and found its new 941s to be anywhere from 50% to 300% stronger in various tests. Part of what made this possible was the hookless bead construction of the rims, which optimizes tubeless tire compatibility while strengthening the bead by replacing traditional musical note-shaped beads with stout rectangles of carbon. Spoke holes are reinforced by additional carbon to ensure strength, too. Ibis opted for traditional J-bend spokes (triple-butted: 2.2 - 1.5 - 2.0), and standard 7075 alloy spoke nipples, all available from your local bike shop in a very-worst-case scenario.

Please check your frame's clearance to ensure that it can accommodate the 941's very wide rims — we'd recommend tire clearance for 2.3in tires at least, just to be on the safe side. Most of the new high-clearance enduro sleds we've seen debuting over the past year or so shouldn't have a problem, but measure twice, just to be safe, especially with pre-2015 bikes.