Bontrager's new Aeolus XXX wheels offer "best-in-class aerodynamics"

Bontrager has released a new lineup of Aeolus XXX carbon road wheels for road, cyclocross, and gravel/adventure. The lineup features three rim depths and a redesigned shape that Bontrager says is lighter and more aerodynamically efficient than its previous designs, with a massively improved braking performance.

The new shapes are designed to provide extra stability in crosswinds, the idea being that you can run a deeper rim without compromising handling. 

“[We] plotted over 10,000 aerodynamic shapes while developing Aeolus XXX, with each new design building on the strengths and learning from the shortcoming of those previous,” says Bontrager. “Shapes were further refined by selecting leading shapes and analysing them each to find the ideal balance between strength and weight. [We] ultimately landed on three unique rim profiles that each provide leading stability, speed, and weight for their depth.”

These are they:

• Aeolus XXX 2 28mm depth, rim weight 370g
Bontrager says, “It’s the lightweight climber that’s strong enough for cyclocross and gravel riding.”

• Aeolus XXX 4 47mm depth, rim weight 430g
Bontrager says, “Do-it-all workhorse performance. It’s the most versatile option for everyday aero performance.”

• Aeolus XXX 6 60mm depth, rim weight 500g
Bontrager says, “Ultimate speed with unmatched stability, bringing an ultra-aero wheel to more riders and conditions.”

Each is available in four different options: tubeless-ready/rim brake, tubeless ready/disc brake, tubular/rim brake and tubular/disc brake. The front wheel is £899.99 and the rear is £1,099.99 in all cases. 

Bontrager says that it concentrated greatly on stability during the development of the Aeolus XXX wheels.

“Reducing aerodynamic drag can give a rider ‘free speed’ but wheel stability is just as important of a consideration in overall rim design,” says Bontrager in a white paper that accompanies this launch. “By increasing wheel stability we can give a rider more confidence to ride a deeper wheel faster, and in more conditions.

“We performed a detailed research study on wheel aerodynamic stability. We started by comparing actual ride wind speed and yaw data with rider feedback indicating feelings of instability. This allowed us to identify riding conditions that can make a wheel feel unstable. Results showed that large changes in steering torque caused by high front wheel side forces is the largest contributor to instabilities. We took this data and coupled it with actual wind tunnel runs of the same wheels at the same wind speed and yaw to identify specific crosswind forces that we needed to design for to make a wheel more consistently stable.”

This figure (above), from Bontrager's white paper, shows drag versus side force (both averaged over 0-20° and rim weight data for the Aeolus XXX lineup and best in class competitors. All data shown here is Bontrager's own.

These figures (above) show the front wheel drag of the Aeolus XXX 4 versus competitor wheels, and the front wheel side force of the Aeolus XXX 4 versus the competition. Again, all data is Bontrager's own.

Bontrager claims that it has addressed the limitations of braking on carbon, particularly focusing on wet conditions. Most carbon wheels fall short in this respect compared to alloy, although Mavic, for example, uses a laser process on some of its wheels to remove the resin from the surface of the brake track while leaving the carbon fibre intact, and the braking performance is excellent..

“Thanks to a unique, laser-etched texture on the braking surface called Laser Control Track, the wheels offer braking performance that is on par with alloy rims while providing better modulation and an increased sense of control,” says Bontrager.

We’ve not yet used these wheels so we can’t comment on the performance ourselves. They’re designed to work with Swissstop Black Prince pads.

These figures show braking lever force versus braking force data for wet and dry conditions on Aeolus XXX wheels with Laser Control Track, Aeolus D3 TLR and Paradigm alloy rims.

The Aeolus XXX rims have a 21mm internal rim width that’s designed to provide support for wider tyres, and come with TLR strips for those who want to run tubeless tyres.

“From an aerodynamic perspective, Aeolus XXX were designed around a 25mm tyre and were also tested with 28mm tyres to validate the aero qualities with wider tyres,” says Bontrager.

The minimum tyre width they’re designed to take is 23mm.

They feature DT-Swiss hub internals with 36-point star ratchets that provide fast engagement when you start pedalling (10°) and they’re laced with DT-Swiss Aerolite spokes. The wheels have no rider weight limits.

All of the rim brake models are available immediately, as are the Aeolus XXX 2 disc models. Aeolus XXX 4 and Aeolus XXX 6 disc models will be available in June.

There’s also a new Aeolus Pro 5, a 50mm deep tubeless-ready, rim brake wheelset that, according to Bontrager, balances durability, weight, and aerodynamics. It’s aggressively priced at £549.99 front, £649.99 rear.

Whereas Aeolus XXX wheels have a new profile and are made at Trek’s Global Headquarters in Wisconsin, USA, the Aeolus Pros are designed to provide a value alternative with profiles borrowed from previous Aeolus D3 models.

www.trekbikes.com