Trek dealers know what a lot of the high end cycling community doesn’t: Bontrager’s parts & accessories are on par with many or most of the best boutique P&A sellers. Specialized has cracked that nut with shoes, helmets, saddles because it started as a P&A brand. It’s harder when you start as a bike brand I think, because the assumption is that your P&A will subordinate to the bike brand, and product development will largely be in service to that brand.
But Bontrager makes really good stuff and its aero wheels, in my own testing, have always been right there with the best boutique aero wheel makers. I had a pair of Aeolus 9 some years back, maybe a decade ago, and in my field trials it was the fastest wheel in my workshop. These were not carefully controlled trials, so, don’t make too much of that. Just… danged if I didn’t always go faster on certain closed courses on those wheels.
There was a flip-side to the speed of that fast wheel, and I don’t want to use technical terms (like “stall”) that might not precisely describe what used to happen to me but, it was kind of a rodeo riding those wheels in crosswinds, and as my field trial courses were on 2-lane roads, if a truck went by in either direction it was a relief to not get bucked off.
This Aeolus 75, which came out a year ago but it’s just taken me this long to come up for air and get a chance to use them – has a lot in common with the old Aeolus 9. These wheels may be fast like those old Aeolus wheels, but I can’t say so with data. There’s a thread on our Reader Forum about these wheels when they first came out, exactly a year ago, with some discussion as to why they aren’t as sketchy a ride as the Aeolus wheels that were so fast-but-temperamental. Maybe it’s a change in the shape; maybe it’s just because they’re 75mm instead of 90mm. Or both.
About that shape, there’s another discussion on our Forum about the Rule of 105 and in that thread I make the observation that it’s a lot easier to conform to this guidance with a toroidal wheel. If your wheel doesn’t have a toroidal shape it’s hard to use a tire larger than 25mm, or even 23mm, and keep to the Rule of 105. But a lot of us have awoken to the virtues of tubeless, and larger tires, and a toroidal wheel shape makes it easier to use a 28mm tire. Toroidal – to those for whom this term is foreign – means the aero wheel’s rim shape, with tire mounted, is more like an oval than it’s like a teardrop.
Is the Bontrager Aeolus 75’s shape toroidal? Well, it depends. It sure seems to me like it’s toroidal, and if you look at my calipers above they’re closed down onto the rim sidewalls and there’s a total of about 3mm of space between the width of the tire and the width of the rim. With a 28mm Vittoria tire on this wheel, the max width of the rim measures about 109% width of the inflated tire. But, there are patents to consider. The original toroidal patent granted HED has since expired, but there’s a subsequent Toroidal 2.0 patent that is in force as far as I know, and that calls out a specific angle between the tire and the rim. I have no idea whether this Aeolus is “toroidal” by that definition.
What I do sense is that this Aeolus 75 might be made for a 28mm tire. It sure seems like that to me. In fact, I had a hard time getting a 25mm tire to bead up, tubeless, inside the expansive 23mm inner bead width of the rim. This rim has a hooked bead and, like Shimano (as one example), not just the hookless wheel makers but the hooked bead makers have migrated to 22.5mm and larger for their inner bead widths.
That rim tape deserves mentioning. That’s called the Bontrager TLR Rim Strip and it’s pretty neat. I am so done with tubeless tape! What I prefer is that the wheel just come to me prepared, with rim tape and valve installed (thank you CADEX and Zipp). But this is the next best thing. It’s a strip you stretch on, kind of like a tubular tire for those who have that history, just, once it’s on if you dismount it Bontrager doesn’t want you to use it again.
So, get it right the first time. It snaps into place, entirely, completely and in the image above I show you what it should and shouldn’t look like. Yes, if you don’t get it all snapped in right the system may fix itself for you, with the air pressure forcing the rim strip into place. But it’s easy just to get it done right yourself. Put the rim strip in place right at the valve hole, then install the valve, then put the rest of the rim strip in place. Note that the valve has a rubber O ring, and that sits between the valve and the rim strip.
When this wheelset is mounted on a Trek Speed Concept, with 28mm tires installed, it’s clear that the bike was made to accommodate this tire size. You could put a 30mm tire on there and there be plenty of room. I don’t know, I don’t want to make a bigger deal out of it than is warranted, but the body language of the wheelset and the bike indicates to me that a 28mm tire is what the designers may have had in mind.
The rest of the wheel is well made, with a ratchet style hub (it’s a DT Swiss hub, and some version of DT Swiss is the hub in the Pro and RSL models). This wheel comes in a 37mm, 51mm, 62mm and 75mm versions, and is an upgrade from Bontrager’s Pro wheels. I have a set of Pro 51 wheels and they’re fine, but the RSL is a better (OCLV) carbon, better hub, better spokes, Bontrager just threw the kitchen sink at the RSL wheel line.
Here’s where you find info on Bontrager’s road wheel line. The RSL 75 is about $2,700 for the wheelset, which places this in the category of surprisingly affordable among ridiculously expensive TT wheels. When I go onto Trek’s Project One website, if I sub in the Aeolus RSL 75 wheelset for the otherwise stock Pro 51 wheelset the upcharge is $1,100, a slight discount from the $1,200 difference in these wheelsets aftermarket ($2,700 to $1,500).
