Bontrager Aeolus 3 D3 wheels

Bontrager's shallowest Aeolus D3 wheels combine impressive aerodynamics with a reasonable weight and predictable handling, making them an excellent all-conditions option.

As you'll probably know, over the last few years many manufacturers have begun to concentrate on the aerodynamics in the section of the wheel where the rim is leading as well as the section where the tyre is leading. Zipp, for example, have focused on this with their Firecrest designs. Bontrager have done so too; D3 means Dual Direction Design.

The result is a 35mm-deep rim that is much broader than a traditional V-shaped aero rim, with a fairly blunt curve on the spoke side – although not as blunt as Zipp use on their Firecrest wheels. Bontrager's sidewalls don't stay wide as long as Zipp's do. Instead, they gradually curve inwards right from the brake track.

The rims are wide at 27mm, the idea, in Bontrager's own words, being to "reach out and 'catch' the flow that separates off the [23mm] tyre before it can create a massive wake."

For a full discussion of why the D3 is shaped exactly how it is you should definitely read Bontrager's white paper on the range. http://media.bontrager.com/images/features/201108_aeolus/bontrager_aeolu... The white paper relates to the tubular line-up rather than to the clinchers but the principles are the same.

Clearly, it's a document that pushes the Bonty way of thinking – they're hardly going to publish a screed that paints their wheels in a poor light – but it gives a useful explanation of the theory behind the D3 wheels and tells you how the various depths compare to one another and the opposition, according to Bontrager's own figures.

According to Bonty, the Aeolus 3 has lower drag than both the 32mm-deep Zipp 202 and the 45mm-deep Zipp 303 at all yaw angles (the combined effect of the actual wind and the movement of travel) from 0° to 12.5°, then beyond that the Zipps have a slightly lower drag.

The biggest difference between the Aeolus 3 and the slightly shallower Zipp 202 is at 10° yaw. There you're looking at a time saving of somewhere between 25secs and 50secs an hour, depending on the bike and the rider. Zipp would doubtless dispute the figures. We're not in a position to give you independent wind tunnel data but here's what we can tell you...

The Aeolus 3s are lightweight for their depth. Bontrager claim a wheelset weight of 1,440g (650g f, 790g r). According to the Road.cc scales, ours came in at 1,479g (667g f, and 812g r, no skewers, no rim tape, 1,521g with rim tape) which is still highly reasonable.

They accelerate quickly, there's no doubt about that, picking up speed with a real rapidity when you come out of a slow turn and stomp on the pedals. More important, they maintain that speed with more ease than any other wheels I've used of a similar depth. They keep on spinning beautifully over a whole variety of terrains and in all conditions.

The other thing you notice is that the Aeolus 3s offer excellent stability in crosswinds. Fair enough, 35mm rims aren't so deep that you're likely to get buffeted around all that much, but when things are blustery you do notice that keeping a steady ship is pretty straightforward with these. You certainly don't find yourself correcting the steering all the time as the wind gusts.

Braking on those carbon rims is fine – not amazing, but fine – as long as you use the Carbon Stop brake pads provided. You don't get the punch that you get with alloy rims but you never do with carbon. It is consistent and reliable, though, so you can adjust your timings accordingly. As well as the pads you get quick release skewers, wheel bags and alloy presta valve extenders as part of the package.

I've ridden these wheels so much over the past few months that I've nearly gone through the entire tread on the rear tyre (sorry Bontrager, but you're going to need to replace them when you get these back) yet both wheels are still running true. You'd be hard pressed to tell that these aren't fresh out of the box. Well, apart from the fact that they're filthy.

They're built with 18 DT Aerolite spokes at the front and 24 at the rear held in place by Alpina locking alloy nipples. The hubs are Bontrager-designed with DT internals, the rear one using DT's Star Ratchet design to provide quick engagement and, in our experience, plenty of reliability. Both Campag and Shimano/SRAM versions are available, including one that's Shimano 11-speed compatible.

Two grand for a pair of wheels is clearly a lot of money however you look at it, but a pair of Zipp 202s will cost you £1,900 and a set of Zipp 303s is £2,300 (list price) so they're roughly in line with those in terms of pricing.

Verdict

Light, superfast aero wheels that handle well whatever the conditions.