In The Know Cycling

The Bontrager Aeolus RSL TLR is Trek’s new entry into the competition for the best everyday road training and racing tire.

Using a high thread count cotton casing, Bontrager appears to be reaching for speed, comfort, and handling benefits that tires with similar casings, like the Vittoria Corsa PRO TLR and Specialized Turbo Cotton clinchers, have become known for.

Our experience riding the Aeolus RSL TLR once again proves the adage that you can’t judge a book by its cover. In this case, you can’t judge a tire by its casing.

Instead, my fellow tester Miles and I found that these Bontragers perform more like nylon casing tires than those suggested by their 320 TPI (threads per inch) cotton casing fiber count.

That’s not a good or bad thing. It’s just a different expectation than we had going in.

With most cotton tires, you need a fair amount of finesse and patience setting them up on your rims and looking after them over time. I happily give the Vittoria and Specialized models the added attention they need for the superior road performance they deliver.

But the Bontrager Aeolus RSL TLR installs, seals, and holds air far better than those cotton casing tires.

They are also one of the more durable road tires we’ve tested, regardless of the casing. For the first hundred or so miles, they feel quite stiff. But after a while, they loosen up and wear at a normal rate, far slower than cotton tires do.

I rode over rough patches of paved roads and gravel sections and through cracks and shallow holes without interruption. Neither Miles nor flatted while riding the tires.

On wheels with 23mm and 25mm internal widths, these 28mm Bontragers measure right around 30mm wide, depending on the inflation pressure. That’s narrower than the 31mm or wider external rim width on most modern wheels with those internal widths and creates a good aerodynamic combination.

Coincidentally, the rim-tire width relationship on the same wheels is similar to that of the 28mm labeled Vittoria Corsa Pro TLR but not as aero as the same size Continental Grand Prix 5000 S TR and Schwalbe Pro One TLE tires.

On the road, the Bontrager Aeolus RSL TLR rides a bit off the pace of the Conti and Vittoria, our top-rated everyday training and road racing tires.

They are louder and feel more rubbery than most. That suggests more rolling resistance than their peers in this category of tires, though it’s hard to predict based on these subjective measures. Bicycle Rolling Resistance drum test scores place them behind the Conti but similar to Vittoria and Specialized’s S-Works Turbo RapidAir 2BR.

To get the best road feel from tires, we’ll typically start with a pressure suggested by the SRAM calculator and lower it in increments on each ride to get more comfort. We’ll stop and bump it up again once the tire’s response to acceleration and cornering becomes too slow or soft.

Neither Miles nor I found a pressure where these Bontrager tires were as comfortable without feeling squishy as the Vittoria and the Specialized, the two most comfortable models of the group. And raising the pressure beyond the recommended level quickly gave us a harsh ride.

Miles estimated the ideal inflation range between harsh and squishy on the Aeolus RSL TLR to be about 5psi. That’s far less than what he’s experienced with the Contis, and it makes it challenging to choose the ideal inflation pressure for a ride or race with varying road surfaces.

That said, once we landed on the right pressure or in the right range, these tires handled and gripped well, but no better or worse than average compared to others in this category.

Overall, the Aeolus RSL TLR is a competitive, if not stand-out, training and racing tire. Its light tan sidewalls are attractive to my eyes. Consistent with modern road tires, Bontrager makes them in 26mm, 30mm, and 32mm sizes, along with the 28mm we tested.

You can order the tires from Trek and Sigma Sports for US$90, £80, €90.

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See how these tires compare to others in my review of the Best Tubeless Tires.