BONTRAGER AEOLUS PRO 37V – A VALUE-PRICED ALL ROAD WHEELSET?
When I set up the Bontrager Aeolus Pro 37V wheels, I was really looking forward to seeing how they rode, more so than most other wheels I test each year.
Why? Well, a little context might help explain.
ANTICIPATING ALL-ROAD VALUE
Bontrager makes their Aeolus wheels in a premium-priced RSL line for paved road use, a value-priced Pro line also for paved roads, and a V line of RSL and Pro-priced wheels intended for riding on both road and gravel.
I’ve rated the Aeolus Pro 37 as one of the best value-carbon road wheels, the Aeolus Pro 3V a solid value-carbon gravel wheelset but average on roads compared to others in its price range, and their premium-priced Aeolus RSL 37V all-road wheels a strong road and gravel performer as well as a great road climber.
Bontrager Aeolus Pro 37V’s predecessors, from left to right, Pro 37, Pro 3V, RSL 37V
The all-road category, a relatively new one of bikes and wheels that perform as well as the best, dedicated road and gravel ones, has been dominated by higher-priced products. And by dominated, I mean that few, if any, value-priced bikes or wheels clear that all-road bar against dedicated, value-priced bikes or wheels.
That’s likely because, in the case of wheels, it takes costly materials, components, and manufacturing processes to make them laterally stiff and vertically compliant enough, wide and light enough, responsive and relaxed enough, and versatile yet capable enough for the performance demanded by the range of surface and terrain we ride in these different cycling disciplines.
It’s a category comprising the likes of the ENVE SES 4.5 and 3.4, the Zipp 454 NSW, 353 NSW, Roval Terra CLX Il, and Bontrager RSL 37V. These true “all-road” performers are as good as the best, dedicated climbing, all-around, and gravel wheelsets. They are “all expensive” too.
I can justify that expense knowing that I only need to buy one wheelset for both my road and gravel rides, change the tires depending on which surface I’m riding, and not give up any performance.
But then I saw that Bontrager was introducing the Aeolus Pro 37V (and 49V) all-road wheelsets for US$1800, £1800, €1800, priced well below those I’ve listed above and not too far above the value-priced dedicated paved or gravel road models.
Knowing that Bontrager was one of the first long-established brands to compete on price and exceed the performance of wheels from the upstart brands and one whose RSL 37V proved to me that they had delivered on the all-road concept very well, I had high hopes for the Pro 37V.
A DIFFERENT KIND OF PERFORMANCE
While I think Bontrager is getting closer to a value-priced all-road wheelset, I don’t find Aeolus Pro 37V meets my all-road definition of being as good as the best dedicated value-carbon road and gravel wheelsets.
The ride feels dampened both on and off-road. This sensation carries some positives and negatives.
On the positive side, the dampening reduces vibration on rough paved, dirt, and gravel surfaces, The Aeolus Pro 37V smoothes the transition over cracks across old, poorly maintained roads. While the wheelset seems to have a narrower band of tire inflation pressures between a harsh and mushy ride, it’s a very comfortable experience across a consistent paved road when I’m in that band.
Mounted up and inflated to the right pressure with 40mm or gravel tires. it’s also very comfortable off-road.
But when the surface changes significantly, for example, when I ride across a 2”, 5cm or deeper road pothole or off a rock onto the dirt on a technical gravel section, I feel a reduced impact but longer vibration through the Aeolus Pro 37V than other wheels I’ve ridden.
No snap or spring comes from these wheels when I make a line change on the dirt or pick up the pace on a paved road. They can feel a bit noodly making a hard turn on gravel, and there’s no zip coming from them out of a fast turn on the road.
Yet, when I want to do a hard acceleration, for example, when I re-engage the pedals quickly, the rear wheel instantaneously reacts as if it were reading my mind. This response is what I need on gravel climbs where I’m on and of the pedals as the pitch seems to change a few percent every few feet or if I’m trying to close a gap I’ve let open on a road group ride when faffing around with a gel or getting caught up in conversation off the back.
In simpler terms, the Aeolus Pro 37V’s compliance is excellent until you hit a sudden surface change when it’s not, and they don’t respond energetically unless you need to reengage the free hub.
KEYS TO A BETTER UNDERSTANDING
Perhaps Sir Winston Churchill’s quote about “a riddle wrapped in a mystery inside an enigma, but perhaps there is a key” applies to the Bontrager Aeolus Pro 37V.
At the risk of having my dusty chemical engineering diploma recalled, one of the keys may be the different properties of thermoset resins used in nearly all carbon bike rims made today and the thermoplastic ones used in the new Aeolus Pro 37V.
Thermoset materials form strong, three-dimensional chemical bonds between their polymer chains during curing that make for mechanically strong, stiff, yet brittle wheel rims.
Thermoplastics don’t create bonds when cured but can be melted and recycled, unlike thermoset rims. CSS Composites, a Utah-based thermoplastic cycling rim and wheelset manufacturer, makes the Aeolus Pro 37V for Bontrager.
The other key (like a safe deposit box, there need to be two keys to open this riddle) is Bontrager’s use of their Rapid Drive 108 hubs that engage every 3.3 degrees. While this is more than you’ll ever need for even the biggest accelerations on road bikes, it is ideal for uneven cadences on steep, soft surfaces riding off-road.
A few other enigmatic characteristics fill out the Pro 37V’s scorecard. By today’s modern wheel standards, their rims are neither shallow nor deep (37.7mm deep per my calipers) but are quite wide (24.8mm inside, 31.5mm outside). Laced with 24 DT Swiss Aerolite bladed spokes, they weigh in at 100 to 250 grams heavier than higher priced all-road wheels (1527 grams on my scale) and don’t climb or maintain their momentum as well as others of similar depth.
VALUE-PRICED OPTIONS
The Bontrager Aeolus Pro 37V performs equally well on and off paved roads. But from my experience, they don’t perform as well as the best value-priced carbon road or gravel wheels.
If you want one wheelset for both surfaces and prioritize comfort over speed and responsiveness, the Pro 37V, available using this link to Trek’s online store or at a Trek dealer, is one of the few value-priced options I’m aware of.
Likewise, if you’ve opted for an all-road bike and ride a semi-slick gravel tire on both surfaces, the Pro 37V will be in keeping with that setup.
But if you want to ride one of the best-performing value-priced carbon wheels for road and gravel, I still think you’re better off getting a dedicated wheelset for each surface.
See how these wheels compare to others in my review of the Best Value Carbon Wheelset.
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Thanks, and enjoy your rides safely! Cheers, Steve