Bontrager adds depth to RSL and Pro wheel ranges

Bontrager Aeolus RSL 51
(Image credit: Bontrager )

Bontrager has updated its top- and second-tier road wheel ranges with new sizes, wider rim profiles and, by using an all-new three-dimensional modelling design process to refine the rim shape, reduce rolling resistance, increase stability and improve aerodynamics. This, according to the brand, has resulted in its best road bike wheels to date, offering a clear improvement in performance over the outgoing Aeolus XXX range.

As with most current bike design, Trek has leveraged an increase in modern computing power, revising the design process and increasing the measurable variables and detail that’s possible to be modelled. Bontrager says this has allowed them to more accurately model real-world conditions and study drag across the whole wheel in every direction. As a result, the new wheels in the 51mm size are claimed to offer a 16 per cent increase in aerodynamics over the Aeolus XXX 4 wheels. The three-dimensional study has not just optimised straight-line speed either as Bontrager claims a noticeable improvement of stability as well. In ‘real-life’, these updates to rim shape add up to a claimed saving of 6.3 watts (RSL 51 TLR Vs XXX 4 Tubular). In more practical terms, Bontrager calculates that as 35.7 seconds faster over an hour of riding at 32.5kph. 

Adding to the existing Aeolus RSL 37 and Pro 37 wheelsets, which were both launched last summer in line with the latest Trek Emonda, the RSL range is given three additional sizes covering 51mm, 62mm and 75mm, and the Pro range gets a single addition with a depth of 51mm. 

Each rim depth is separately optimised as differing rim depths have different demands on aerodynamics and stability. Both the RSL and Pro of the same size use the same rim profiling and manufacturing techniques, what differs are the materials used. The Pro rim uses a Pro OCLV carbon while the RSL rims use a lighter and stronger RSL-level OCLV carbon.


(Image credit: Bontrager)

Wider rims for better aerodynamics

Bontrager hasn’t just reworked the shape, they also studied rim width and has settled on a 23mm internal rim diameter for all new models, while both 37mm models remain narrower at 21mm. 

The reason for the wider rim is that Bontrager found this width optimised a closer aerodynamic connection between a 25mm tyre and rim. All the wheels come in tubeless clincher options only which, combined with the wider rim, will allow lower pressures to give more grip and comfort but reduce rolling resistance when compared to tubulars. The narrower 37mm deep rim is aimed at climbers and the prioritisation of lightweight rather than aerodynamics resulted in the rim width remaining at 21mm, helping to save around 30g.

All the wheels use DT Swiss hubs and are built with DT Aerolite spokes (24/24). The Aeolus RSL wheels are built around a hybrid of DT Swiss’s 240 and 180 hubs with a Ratchet EXP 36-point engagement 11-speed freehub. To make the Pro models more budget-friendly, Bontrager has chosen DT Swiss 350 hubs with 18-point engagement and SRAM/Shimano 10/11 freehubs. If you are running a 12-speed cassette, compatible freehubs are sold separately. Bontrager includes TLR rim strip, TLR valve and traditional rim strip so that all you need is tyres and sealant to get rolling.

Bontrager will sell all the wheels individually to allow consumers to mix and match wheel depths to find the best setup for their riding. All the wheels are warrantied for life from manufacturer defects and the wheels don’t have a rider weight limit either. As a bonus, if you damage your wheels within the first two years of ownership, Bontrager will replace your wheels free of charge under Trek’s Carbon Care program.

Pricing on the Pro version is set at £1299.98 / $1299.98 / €1299.98 whereas the premium RSL range retails for £1999.98 / $2399.98 / €2399.98 across all the sizes.

Bontrager Aeolus RSL specs

  • Height: 37mm, 51mm, 62mm and 75mm
  • Weight: 1325g (37mm), 1410g  (51mm), 1520g (62mm) and 1654g (75mm)
  • Inner rim diameter: 21mm (37mm), 23mm (51mm, 62mm, 75mm)
  • Hubs: DT Swiss 240s internals with Ratchet EXP 36-point engagement
  • Spokes: DT Aerolite spokes 24/24, DT ProLock nipples
  • Price: £1999.98 / $2399.98 / €2399.98

Bontrager Aeolus Pro specs

  • Height: 51mm
  • Weight: 1590g (51mm)
  • Inner rim diameter: 23mm (51mm)
  • Hubs: DT Swiss 350 internals with 18-point engagement
  • Spokes: DT Aerolite spokes 24/24, DT ProLock nipples
  • Price: £1299.98 / $1299.98 / €1299.98 

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Graham has been part of the Cyclingnews team since January 2020. He has mountain biking at his core and can mostly be found bikepacking around Scotland or exploring the steep trails around the Tweed Valley. Not afraid of a challenge, Graham has gained a reputation for riding fixed gear bikes both too far and often in inappropriate places.