gravel wheel aero testing – Ascent Big Chungus

I've done some aero wheel testing in the past but wanted a look at some of the newest stuff coming out…in this case, something you aren't going to see on many bikes yet! Ascent's offering tested here, the Big Chungus, had some specs that caught my eye so I got them. 32 mm internal width with a hooked rim, 40 mm external width, 59 mm front rim depth with a 54 mm rear, 24 CX ray bladed spokes front and rear, all with a quite competitive weight of under 1450 grams for the set. Serious business.

Everything about these wheels is absurd, including how fast they are. I tested these back to back (identical bike, tires, rotors, and cassette) with Reserve's 25GR shallow gravel wheels with a rim depth of 18 mm. They have similar bladed spokes to the Ascent's. 29 x 2.1 Thunder Burt's measure 52 mm wide on the Reserves and 54.6 mm wide on the Ascents so I ran 1 psi less on the bigger set to equalize things. If the CRR values look a bit lower than some others, it is due to increased temperature outside.

I had super good weather for these tests, as seen by how clean the Virtual Elevation plots are! The results are quite clear, with a savings of .017 CdA for the Ascent wheels vs baseline. This works out to a savings of 7 watts at 32 kph and 23 watts at 48 kph…again, serious business. These are without a doubt some of the fastest gravel wheels on the market, and only a couple ticks off the even wider new Enve G SES 6.7s but lighter.

The absolute CdA values are for my Trek Checkpoint in upright hoods position, which is actually quite similar to some of the fastest aero gravel bikes in the recent CyclingNews wind tunnel testing. I mention this as it is still true the rider is the biggest portion of aero drag, so get your fit dialed first and foremost! For anyone looking at a set of the Big Chungus hoops, holler at the Bicycle Station crew or direct at Ascent.