Conclusion: The tyre is becoming an aerodynamic component
Gravel tyres are designed to roll smoothly, provide grip and be as puncture-resistant as possible. Apparently, that’s no longer enough for WTB. With the Byway RS, Course and Macro models, the US manufacturer is launching a new generation of wide gravel tyres that focus not only on rolling resistance and grip, but also on aerodynamics. To achieve this, small vortex elements and so-called ‘Trip Strips’ are incorporated into the sidewalls to better control airflow.
Sounds like a marketing gimmick? Perhaps. However, according to the manufacturer, the test results are remarkable: in collaboration with Stromm Cycles, a power advantage of 5.8 watts at 30 km/h, 9.3 watts at 35 km/h and 13.8 watts at 40 km/h. For fast gravel races in particular, this approach could therefore mean more than just a nice detail on the sidewall.
Key facts
- Three new models: Byway RS 50, Course 52 and Macro 54
- Aerodynamic technology: Vortex elements and trip strips on the side walls
- Up to 13.8 watts less aerodynamic drag at 40 km/h according to WTB/Stromm
- 120 TPI carcass for a smooth ride
- SG2 Puncture Protection continuously from bead to bead
- Dual-DNA rubber compound with a fast centre and grippy shoulders
- 50 to 54 mm wide depending on the model
- Weights: 620 to 640 grams
- Black or tan-coloured side panels
- Price: 79.95 euros RRP
WTB is rethinking the gravel tyre
With these three new tyres, WTB is pursuing a clear concept: increased volume is not just intended to provide comfort and traction. The tyre is also designed to cut through the airflow as cleanly as possible.
To this end, WTB has optimised the entire carcass for modern gravel wheels with an internal width of 25 to 32 millimetres. The focus is particularly on the 28-millimetre width. The wide rim, together with the tyre, forms a controlled surface. This is precisely where the aero structures come into play.
Vortex elements and trip strips influence the flow along the tyre sidewall. They are designed to reduce turbulence behind the tyres and wheels, thereby lowering aerodynamic drag. The effect increases significantly as speed rises.
At 30 km/h, WTB quotes a power saving of 5.8 watts. At 35 km/h, this is said to rise to 9.3 watts. At 40 km/h, the figure rises to 13.8 watts. For leisurely gravel rides, this is unlikely to blow anyone away. However, anyone who competes in gravel races and regularly races around the course at 35 or 40 km/h should take a closer look.
Stromm brings wind tunnel thinking to the track
WTB enlisted the support of Stromm Cycles for the development. The company had already been working on a particularly fast UCI-compliant road bike and has now applied its aerodynamic expertise to the tyres.
Stromm tested the design using the Chung method and compared the new tyre with an identical model without aerodynamic features. The tests took place at the Jerry Baker Memorial Velodrome in the US state of Washington.
According to WTB, the team did not just test clean tyres. Dirty surfaces were also taken into account in the measurements. This is a very important point: gravel tyres are rarely used under laboratory conditions. Dust, dirt and mud are part of everyday life.
Three tyres, three characters
Byway RS 50: top speed
The Byway RS is the flagship of the new range. A smooth centreline and shallow transition tread blocks are designed to minimise rolling resistance as much as possible. The shoulders provide grip as soon as the terrain becomes looser.
With 620 grams It also remains the lightest of the three models. Tarmac, hard gravel and fast race tracks are its natural habitat.
Course 52: the all-rounder
The Course 52 bridges the gap between speed and off-road performance. Its tread pattern offers more grip than the Byway RS, without turning the tyre into a specialist for rough terrain.
635 grams It weighs in at 52 in width. This should appeal particularly to riders who don’t want to fit a different wheelset for every race, but are looking for the right tread pattern to suit all situations.
Macro 54: when the gravel gets coarse
The Macro 54 takes it a step further off-road. 54 millimetres wide, with taller, more widely spaced lugs and the largest volume in the range, designed to provide control on loose, stony and technically challenging terrain.
With 640 grams It weighs just 20 grams more than the Byway RS. In return, it offers significantly more tread pattern and volume, but also the highest rolling resistance.
Puncture protection and aerodynamics go hand in hand
Despite all the excitement surrounding aerodynamics, WTB hasn’t forgotten about traditional tyre design. All three models feature a revised 120 TPI casing and come with continuous SG2 puncture protection.
The combination with the Dual-DNA compound remains an interesting feature: WTB has opted for a fast-rolling rubber compound on the tread and softer, higher-grip shoulders. The tyre is therefore designed to maintain speed on straights and provide good grip when cornering.
The real trick lies in the side panel
With its Aero range, WTB picks up where traditional tyre development focuses primarily on protection, stability and grip: at the junctions with the sidewall. On the new WTB tyres, inconspicuous aero structures are located there alongside the outer lugs. The claimed effect, however, is anything but minor.
However, the same applies here: The The 13.8-watt saving applies only under ideal conditions at a specific speed. This figure is taken from WTB’s comparative test carried out under defined conditions. On the road or on a gravel track, speed, the rider’s position, the wheel, the rim, the tyre width and the surface all affect the actual result.
Editorial commentary
WTB has struck a chord with this new range. Gravel cycling has long since evolved into sub-categories, shifting from leisurely gravel rides to competitive racing – and as a result, aerodynamics is becoming an increasingly important focus. You can now even buy specialist aero gravel bikes. Although tyres on gravel bikes were long regarded primarily as a means of providing greater comfort and control, it is only logical that, with this trend, there is now also a demand for tyre solutions that reduce air resistance.
We will have to test whether the promised extra power actually remains so noticeably evident in everyday use and can be replicated. The technical approach is nonetheless worthy of attention.
Price and availability
WTB quotes a RRP of 79.95 euros. The Byway RS, Course and Macro are available with black or tan sidewalls and are set to be available worldwide via WTB retailers, distributors and directly from the manufacturer. These are joined by new CGR Carbon Gravel Wheels, which WTB has also announced and which are intended to round off the aero concept.
Max Fuchs
Editor