Reynolds Assault SLG disc brake wheels

The Reynolds Assault wheelset has proved popular for road and cyclocross use since its launch, offering some clever aero technology at a fairly competitive price. Now the mid-depth clincher rim is available with a disc hub, making a compelling choice for cyclocross racers and early adopters of road disc brakes.

During our review we ran the Assaults on the road exclusively, so we can't comment on their off-road toughness, but in general deep-section carbon wheels tend to cope well off-road so we would expect they would work well in the mud.

The clincher rims are 41mm deep and 25mm wide, with the distinctive Swirl Lip Generator noticeable on the sidewalls near the spokes. The 2014 model has a larger lip than previously; Reynolds say the new Enhanced Swirl Lip Generator is in fact eight times larger at just under 1mm tall.

Reynolds claim that the Swirl Lip Generator "helps turbulent air passing over the wheel to reattach to the spoke face after flowing over the spinning rim" and that wind tunnel testing shows a 35% aerodynamic benefit compared to the previous generation rims without Swirl Lip Generator. Thirty-five percent sounds a lot, but this only relates to the drag of the wheel (itself a small proportion of your overall drag).

I am a little sceptical about how air flow measured around a stationary bike in a wind tunnel really correlates to real-world use, where the interaction between rider and bike, plus the side-to-side pedalling motion would surely complicate things. In any case, Reynolds have done more wind tunnel testing than I have, so perhaps we'll have to let that one be.

These wheels are sensibly built to take the extra forces experienced with disc brakes, with a higher spoke count (24 front and rear) and two-cross spoke lacing all round. Straight-pull Aero Comp bladed spokes from DT Swiss are used. The rims do not have a brake track, saving weight, and the result is a competitive 1565g claimed weight (compared to 1597g as measured on arrival here). Clinchers are available now and tubs will follow soon, and should be a bit lighter.

The hubs are 11-speed compatible (we ran them with the new Ultegra Di2 groupset) and compatible with six-bolt rotors only. We don't have too much other information about the hubs, but we had no issues with them during the review.

The wheels arrived true and remained so during the review period with no trueing needed, even after a fairly painful meeting with a pot-hole that resulted in a flat. They are a smart-looking set of wheels, with graphics not as garish as some. To our surprise, we found that the Reynolds logos started to come off after a few hundred miles: they don't appear to be protected by a top-coat.

We fitted the wheels to the Culprit Croz Blade in place of some fairly basic Shimano RX31 wheels and unsurprisingly the difference was noticeable, with the reduction in inertia giving sharper acceleration and the deeper section rims making it a little easier to hold speed once you'd got going.

At 41mm they are a mid-depth rim, which you'd expect to offer a decent compromise between aerodynamic efficiency and stability in the wind. We had a few issues with high-speed stability in the wind when they were paired with an aero frame, but on a standard-tubed bike they were well behaved even in very gusty conditions, so it was probably the combination of the frame and wheels together, rather than just the wheels, that was the issue. Reynolds claim that the Swirl Lip Generator reduces the side force on the rim due to cross-winds. Without seeing the data, this sounds slightly counter-intuitive, but we were not able to make measurements to confirm it one way or the other.

At this price-point Reynolds is positioning the Assault Discs below the really expensive exotica. Given that you're getting a wheelset specifically developed by a big-name brand with the benefit of their considerable aerodynamic expertise, and backed by the Reynolds Assurance Program (giving discounted replacement or repair in the event of a crash), we think they are decently-priced. Rim tape and quick release skewers are included; wheelbags are not.

These are reliable and reasonably fast wheels. Reynolds makes big claims for the efficacy of the Swirl Lip Generator that we were not able to prove or disprove. They are a reasonable price given they have been developed in-house rather than assembled from a Taiwanese parts-list. We'd expect them to be very popular amongst serious cyclo-cross racers and road-disc early adopters.

Verdict

Good, reliable carbon disc wheels that will suit cyclo-crossers and road disc early adopters.