A year now on my 2018 Levo Carbon and I had immediately replaced the stock Roval aluminum 27.5 x 40mm inside width to my carbon fiber Derby 29 x 40i AM 32H AM with 2.6 tires on the front and Derby 278.5 x 45i AM 32H with 2.8 tires on the rear, both with Onyx Racing Products hhubs with rear steel casette driver. The Derby carbon rim and heavier Onyx hub wheel weight difference is 2 lbs lower than the stock Roval aluminum rim wheels.
The mullet 29/27.5 is a noticeable improvement in rollover especially while descending. Handling with stock wheels was balanced, and with mullet wheels also balanced and smoother rolling. I tried a Derby 29 x 40i with 2.6 rear also, which added a little in smoother rollover, but reduced climbing and braking rear traction.
A friend on the same model 2018 Levo with stock 2 lb heavier wheels and same tire model Schwalbe Eddie Currents, and I on my Derby's did battery use distance comparisons. We are nearly the same weight, and climb and handel bikes nearly the same also. The 2 lb lighter carbon Derby/Onyx wheels did not improve battery use more than about 1 or 2% better compared to the stock wheels over a long ride draining our fully charged batteries to 10%. We had both set our Mission Control power settings to be much lower than stock default power mode settings except hard pedaling turbo mode (100%). And we stayed in eco mode as long as possible, and had changed power levels up for steeper climbs at the same time.
Changing tires to lighter and easier rolling Schwalbe Hans Dampf front and Nobby Nic rear tires made a much bigger difference. Weight is about 635 g or 1.4 lbs lighter than Eddie Currents, and the easier rolling treads enabled close to 10% less battery use measured in the same overall miles covered on the same long battery draining ride with similar mainly dry trail conditions.
Here's a little self promotion if considering carbon fiber rims for any bike. Derby Rims are well proven as the most durable carbon fiber rims, not the lightest and also not the heaviest for a given rim wheel size size and width. Nearly every Derby mountain rim model has had a less than 0.5% damage rate during the last 3 years, and a large majority of the rare damage was for Derby rims that were over 2 to 6 years old. Only the 27.5 x 35i AM has a higher rate near 1% during the last 3 years, I suspect due to the most harsh Enduro DH type high speeds over rocks frequently bottoming suspension or large drop landings onto rock landings, which is abusive use of any AM equipment. AM is NOT Enduro. AM is and always has been technically difficult trail climbing oriented with technical difficult trail descending at moderate speeds. Enduro DH high speed and free-ride large drop stunt riders should be on Derby DH rims for best 0.5% damage rate durability. The Derby road width 25mm inside and narrower rims, normally used for mountain XC, road, and gravel road bikes, have never been reported damaged in 4 years of availability.
26mm inner I think or 28.
