BONTRAGER AEOLUS PRO 51 – QUIET COMFORT, LACKLUSTER RESPONSIVENESS
I had high hopes for our testing of the US$1500, £1250, €1800 Bontrager Aeolus Pro 51 TLR wheelset. We rated its shallower and similarly priced sibling, the Aeolus Pro 37, one of the best value bike wheels for its capable range of performance. And our review of the Aeolus Pro 51’s more expensive twin, the Aeolus RSL 51, which shares the same rim profile, carried the headline: The Definition of an All-Around Road Disc Wheelset.
I, and probably many of you, keep looking for that value-priced wheelset that rides nearly as well as one that costs twice as much. Using a set of performance criteria (not specs) to evaluate wheels, my fellow testers and I have ridden over a dozen value carbon road bike wheels (and another half dozen gravel ones) over the last few years in search of one that would save you a bucket full of money without giving up more than a shot glass worth of performance.
Unfortunately, the Bontrager Aeolus Pro 51 isn’t it.
Like all but a few wheelsets in this price range, the Pro 51 performs adequately in some areas and less so in others. From the rides that fellow tester Nate and I did, the Pro 51 doesn’t match or approach the overall performance we enjoyed of its RSL 51 sibling or the balance of good performance across areas like its shallower Pro 37 kin does.
Comfort is the Aeolus Pro 51’s biggest strength. Its wide rim profile allows you to run 28mm tires without sacrificing aero performance while keeping the pressure low enough to soak up the bumps on paved, poorly paved, or unpaved roads quite nicely.
True, the right tire and pressure are a big part of enjoying a comfortable ride these days. But I’ve ridden enough wheelsets, especially in the value carbon price range where the rim/spoke/hub component choices, lacing, or assembly don’t enable enough vertical compliance in the wheels for a comfortable ride regardless of the tires and range of pressures I tried.
The Pro 51 felt planted in corners though accelerating out of them was underwhelming. They’re stiff enough to confidently get you through but not responsive enough to get you flying out.
That lack of responsiveness also showed up during acceleration efforts. They were not at all lively. It took a lot of effort to get them up to speed.
Once up to speed, it took more effort to keep them there compared to the best wheels at this price point and more expensive ones. That was disappointing since the Pro 51 uses the same rim shape as the RSL 51.
While aero performance, which we judge based on our ability to maintain momentum in the 20-25mph/32-40kph range for the RSL 51, was good but not exceptional compared to top-performing all-around, the Pro 51 isn’t on par with the RSL 51.
The common rim profile gene did show up in the Pro 51’s good stability in side winds. That’s a welcome benefit if you ride where it is regularly windy.
Climbing with the Pro 51 was a drag, figuratively and literally. Even riding a course with rolling hills took more effort than a wheelset this depth should. 7% grade climbs put me in the hurt locker the way 10%+ ones normally do.
All of this made me feel like I had “dead legs” when riding the Pro 51. I do get those days regardless of the wheelset and certainly feel that way when trying to climb or ride aggressively on most 60mm deep wheels rather than the straight flats they are designed for. But I should feel better than that on a good set of all-around wheels of the Pro 51’s depth and profile.
Nate put a finer point on it, saying the Pro 51 wheelset’s responsiveness was “dull.”
Design: The Aeolus Pro 51 measured 1625 gram weight likely contributes to its relative lack of responsiveness, acceleration, and climbing ability. That measurement is with about 15 grams of tubeless rim tape and no valve stems. If you instead install the 60-gram per wheel plastic tubeless strips that Bontrager includes in the box, well, we’re getting into stock wheel weight territory.
Even with the TLR rim tape, the Pro 51 is almost 200 grams more than the RSL 51 (1441 grams measured) and even 50-100 grams more than my top-rated aero wheels, which are 10mm deeper and more aero.
I don’t know how much of that extra weight is in the rims where it matters most vs. in the hubset. Bontrager uses the DT Swiss 350 hubs in their Pro line of wheels, which, while heavier than the DT Swiss 240 EXP, are infinitely quieter. Quieter, as in absolutely silent.
While there may be a performance difference between the 240 and 350, I can’t feel it on the road. But I sure do notice the solitude of a quiet freehub.
As mentioned, the Pro 51 rims are wide, measuring 23.2mm inside and 31.0mm outside, with an actual depth of 51.5mm.
Design: The Aeolus Pro 51 measured 1625 gram weight likely contributes to its relative lack of responsiveness, acceleration, and climbing ability. That measurement is with about 15 grams of tubeless rim tape and no valve stems. If you instead install the 60-gram per wheel plastic tubeless strips that Bontrager includes in the box, well, we’re getting into stock wheel weight territory.
Even with the TLR rim tape, the Pro 51 is almost 200 grams more than the RSL 51 (1441 grams measured) and even 50-100 grams more than my top-rated aero wheels, which are 10mm deeper and more aero.
I don’t know how much of that extra weight is in the rims where it matters most vs. in the hubset. Bontrager uses the DT Swiss 350 hubs in their Pro line of wheels, which, while heavier than the DT Swiss 240 EXP, are infinitely quieter. Quieter, as in absolutely silent.
While there may be a performance difference between the 240 and 350, I can’t feel it on the road. But I sure do notice the solitude of a quiet freehub.
As mentioned, the Pro 51 rims are wide, measuring 23.2mm inside and 31.0mm outside, with an actual depth of 51.5mm.
Quality: The matte-black rim finish on my tested set didn’t clean up very well. No matter what I tried, the finish looked quite blotchy. While you don’t buy matte-black rims for their finish, and the blotchy look is only visible when you look closely in the right light, it’s disappointing nonetheless.
Bontrager’s service policies should cover this issue. You can ride (and clean) the wheels and still get a full refund within 30 days of your purchase if you decide you don’t want to keep them. They also come with a lifetime materials and workmanship warranty.
The crash replacement policy for these and all of Bontrager’s carbon wheels is decent, if not the best. They will replace or repair your wheels for free within two years of you buying them if you damage them while riding.
As they are owned by Trek, which has one of the largest dealer networks, you can take your Bontrager wheels to any bike shop that sells Trek products for warranty or crash replacement service.
Price: You can use these links to order the Bontrager Aeolus Pro 51 TLR wheels direct for US$1500, £1350, €1750 from Bontrager and Sigma Sports.
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You can read my evaluation of other wheelsets in this category in the post The Best Value Carbon Wheelset.
Hi. I recently bought a set of these after a recommendation from my local bike shop due to my weight and their shorter spoke length for strength . I primarily value the comfort these wheels provide over my stock affinity wheels and some aero benefit . It so much for racing characteristics . Would you say the Aeolus 37 version of these are as comfortable or less ? Just curious if I would still have the same benefits . Thanks !
The Real Person!
Andrew, you can improve your comfort with changes in your tire size and pressure alone. Spoke length is only one aspect of what leads to wheelset stiffness and strength and short spokes typically make for less stiff/strong wheels. Body position is 5x to 10x more important than wheelset depth. The effect of a wheelset’s depth on aero performance is unnoticeable until you are riding at racing speeds. Depending on your situation, the Aeolus Pro 37 can be as comfortable or less so than the Aeolus Pro 51. Review of the Aeolus Pro 37 here: https://intheknowcycling.com/bontrager-aeolus-pro-37-review/. Steve
Okay thank you for the input. So it sounds like you are saying the Aeolus 37 would be a stronger wheel? Sorry I was going based on what my local shop recommended regarding the spoke length and strength and thus bought the 51’s. The other option I was considering was a HED Ardennes aluminum wheelset instead of carbon at half the price. I am 250lbs now but I plan to get down to 190lbs so I am sure all of this will change as I get in proper condition. But, I just listed the Aeolus Pro 51’s on ebay as I think I might have made a mistake getting a wheel that won’t really make much difference over dropping my psi and maybe going to a 32 over a 28 tire size. I do think some aero benefit would be helpful but maybe not that important over the other factors you mentioned. Just looking for the best wheel for my bike as a non-racer. I have a 2019 Trek Domane if it helps.
The Real Person!
Andrew, there are a lot of considerations in choosing the best wheelset for each of our situations. I’d suggest you work through this post to help you choose. https://intheknowcycling.com/how-to-choose-bike-wheels/. If that doesn’t get you there or you want a personalized recommendation, I do that for Know’s Club Leader members. Steve
I have a new 2022 Trek Emonda SL7 with the SRAM E-Tap setup. I also have the BONTRAGER AEOLUS PRO 51 sheet set wrapped in a set of Bontrager R3 28mm tires. I am not running tubeless. I have the air pressure at 110 PSI. Is that too high? The rim says max 120 PSI. I weigh 225 lbs.
The Real Person!
Ke, Yes, that’s far too high. Tire pressure guides like this one https://axs.sram.com/guides/tire/pressure would suggest 70-75 psi for your setup. Steve
So I lowered to the psi that you recommend and the wheels felt like a sloth. Flat out too. Interesting how SRAM states one thing but the Bontrager states max PSI is 120.
The Real Person!
The max psi has no relationship to the recommended psi. With wider wheels and tires, you’ll go faster with far lower pressures than what you may have set in the past. You can read more about this and see tire pressure guides from ENVE and Silca that get you to a similar recommended range as the SRAM guide at this link: https://intheknowcycling.com/how-wide-wheels-wide-tires-make-you-faster/#IV
I think if you update the dt swiss ratchet to 54t is a pretty good wheelset for that price. Which wheelset do you prefer then in the same price range?
The Real Person!
Eric, Perhaps. It’s hard to pinpoint exactly what makes for a more responsive wheelset but some combination of stiffness, aerodynamics, weight, carbon layup, hub engagement, spoke placement, and perhaps other factors will determine how responsive a wheel is when you try to accelerate. The Aeolus RSL 51 is more responsive and has the same rim profile and points of engagement in its hub but uses a different carbon layup and is about 250 grams lighter.
Check out this review of value carbon wheelsets for some better options. Steve
Thanks for your answer.
Have you tested the ultegra 8170 c50 wheelset?
The Real Person!
Eric. Haven’t tested it and probably won’t. Like a lot of Shimano parts right now, it’s hard to find. The specs also suggest it may not be worth the time – 1600 grams for a 21mm inside, 28mm outside width wheelset. BTW, you can use the search bar at the top of any page to look for mentions or reviews of wheels you are interested in. Steve
I have this wheelset. No issues. I’m right there with the rest of the group. I fly by folks with more expensive wheelsets and bikes. I’m sure there are marginal gains with better wheels. But if you’re not a racer, I don’t think the rest of us will notice marginal gains or losses. I’m also 225 pounds so responsiveness will come with more riding and less weight!
Thanks you the detailed review.
What would you recommend as a all-round very light (56kg) rider – Bontrager aeolus pro 51 or 37?
Would I see any aero gain difference?
Do they catch crosswind differently?
The Real Person!
Alon, Unless you’re a very strong rider for your weight (>200-225 watts FTP or nearly 4w/kg) that rides > 22mph ave, I’d suggest the Pro 37 between those two wheels. Below those performance levels the Pro 51 will feel sluggish and won’t give you any aero benefit. They won’t be much fun going uphill. You can read my review of the Pro 37 and other wheels at this price point in my review of the best value carbon wheels. Steve
Thanks Steve.
I’ve read the 37 review and this one. I think I’ll take your advice and go with the 37mm.
BTW: Does the crosswind feels different?
The Real Person!
Won’t be a big difference. The Pro 51 is pretty good in the crosswinds for its depth
Just purchased a bike with Aeolus Pro 51 wheels. From what I take from your article I would achieve better performance if I upgrade to Aeolus RSL 51 wheels. Is my understanding on target?
The Real Person!
Edward, If fast acceleration and quick responsiveness is important to your performance and you frequently ride on rolling hills and have steeper climbs on your routes, you’ll get notably better performance with the RSL 51.
Im curious if those Pro51 could be a good gravel wheelset ?
I have a deal a lbs and wondering since they are market as road wheels.
Any toughts?
The Real Person!
Danny, I didn’t test them on gravel but based on my road testing, I wouldn’t think they’d be great on gravel. They’ve just replaced the Pro 51 with the Pro 49V and Pro 37V. We are testing those wheels now. Steve
Hi Steve, I am curious to know your thoughts on the Pro 49V compared to the Pro51 and RSL51. Thanks!
The Real Person!
Ryan, I’ll have a review up next week about the Pro 49V. I appreciate your patience until then. Steve