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.
Light, superfast aero wheels that handle well whatever the conditions.
road.cc test report
Make and model: Bontrager Aeolus 3 D3 wheels
Size tested: Shimano
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Bontrager say, "The climber's choice. Our D3 rim profile in a 35mm height yields an amazingly light wheelset with the aerodynamics of a far greater rim profile. There is no better way to make your bike perform better than removing rotational weight, and there is no better, lightweight clincher wheel system. Includes full OCLV carbon rims and silky smooth, Swiss-made hubs."
These are high-performance wheels that are suitable for all kinds of terrain and conditions.
Tell us some more about the technical aspects of the product?
The best thing to do if you want more tech info on these wheels is to check out Bontrager's white paper.
I've given these a right old battering over the past three months and they've just shrugged it all off.
Aerodynamic, light, stable... spot on. The braking performance isn't amazing but it's good by carbon's standards.
See above, they're doing great.
Of course, you can get lighter wheels by going for wheels with a shallower rim depth but the aero performance more than makes up for that.
Weeeeeeeell, they're expensive, of course, but considering the technology and the quality it's not a crazy price.
Tell us how the product performed overall when used for its designed purpose
Beautifully. Very impressive all round.
Tell us what you particularly liked about the product
The speed and stability in all conditions.
Tell us what you particularly disliked about the product
Like all carbon rims I've ever used, the braking performance lags behind aluminium.
Did you enjoy using the product? Yes.
Would you consider buying the product? Yeah, with someone else's money.
Would you recommend the product to a friend? Yep.
About the tester
Age: 41 Height: 190cm Weight: 75kg
I usually ride: My best bike is:
I've been riding for: Over 20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, club rides, sportives, general fitness riding,
Mat has worked for more bike magazines than anyone else in the known universe, dating back to a time when this was all just fields. He's been road.cc technical editor for four years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. When he's not cycling around Wiltshire, he's running around it, or possibly swimming (sadly, he's one of those 'triathletes'). Mat is a youthful 42-year-old Cambridge graduate, GSOH etc.