Easton claims its new EC90 Aero 55 tubular road wheelset is the "fastest 50-60mm wheel on the market". Not surprisingly, we approach such bold statements with more than a few grains of salt. We unfortunately don't have our own wind tunnel data to support or refute that claim but after several months of testing, we can at least confirm that they're very obviously wickedly speedy.
The EC90 Aero 55's 55mm-deep 'Fantom' rim shape takes the current wider-is-better philosophy to new, uh, widths. The external measurement at the brake track is already monstrous at 28mm but the rim flares out even further to 30mm closer to the midsection (1.5mm wider than Zipp's latest 303 Firecrest tubulars). As with other modern aero wheels, the fat shape terminates in a notably blunt nose, all of which stands in stark contrast to the narrow and sharp V-shaped profiles used just a few years ago.
In contrast to the old V-shaped rims of days gone by, the Easton EC90 Aero 55 profile is very distinctly blunt and fat
Out on the road, it doesn't take long to discover that the EC90 Aero 55s are gloriously speedy, especially when compared with a more traditional, non-aero wheel. Sure, the excellent wheel stiffness, feathery 1,353g actual weight (587g front, 766g rear, plus 141g for skewers), and low rotational inertia make for a quick start off the line and a pleasantly light feel when climbing but, as is always the case with aerodynamics, the tangible effects are much more noticeable the faster you go. What's most impressive here is how much faster you can go with the same amount of effort as compared to something with more drag – or, conversely, how much easier it is to maintain the same speed as compared to a wheel with more drag.
Our bodies aren't as finely tuned as a proper wind tunnel, however, so we can't say for sure if the Eastons are actually any faster (or slower) than comparable aero wheels of similar depth. We can say, however, that the distinctively round shape is impressively easy to keep stable in swirling crosswinds and still feel fast even when the wind conditions are less than ideal.
Easton says the very blunt nose and rounded rim shape helps with crosswind stability – and we tend to agree
One typical ride here in BikeRadar's US headquarters in Boulder, Colorado heads straight north out of town, directly perpendicular to the brutal Chinook winds that regularly pepper the area each winter. Whereas we're usually loathe to head out in those conditions with aero hoops, the EC90 Aero 55s proved to be one of few models we felt comfortable on in nearly all conditions – a particularly important thing to note for interested buyers who aren't going to have the luxury of swapping wheelsets with changing weather conditions.
We were also impressed with the new Echo rear hub design, which now not only spreads the main, outer axle bearings 95mm apart (more than twice the distance of Easton's previous R4 SL hubs) but also supports the new aluminum freehub body with an enormous angular contact cartridge. The new setup no longer includes an adjustable bearing preload feature – but that's just fine, since it's no longer necessary. Our rear hub started out silky smooth and has stayed that way throughout testing.
With the freehub body removed, you can see just how far the main cartridge bearings are pushed apart, which bodes well for longevity
Some – ourselves included – might find the 52-tooth driver ring's quick 6.9-degree engagement speed to be overkill for the road. However, the rim's wide profile makes these wheels a perfect candidate for cyclocross, too, where that responsiveness would be much more applicable. Either way, there's no noticeable additional drag as a result, and as long as you're ok with the slight buzziness that resonates from the rear end while coasting, we have no issues with it.
Unfortunately we can't say the same for the other end. The front hub shares the rear's slick oversized body, stainless steel spoke flange reinforcing rings and wide bearing spacing. However, it wasn't long before our front hub developed a tiny bit of play – not enough to impact overall wheel performance but certainly more than we'd prefer to see in a wheelset that costs as much as it does.
Stainless steel rings reinforce the big aluminum spoke flanges, which not only adds strength but adds a bit of visual flair
Easton says that it is aware of the bearing issue and has already corrected it in later production runs.
"We have made running changes on the front and rear hub bearings," said wheel engineer Brendan O'Brien. "They now include tighter internal clearance values which directly affect play.”
Brake performance was a bit mixed, too. In dry conditions, the included SwissStop pads don't have much initial bite but ramp up nicely with increasing lever pressure and, save for when they get very hot, they're generally quiet without any of the pulsing we've sometimes encountered with other carbon wheels. Wet braking performance is… well, it's still a carbon rim, so it's expectedly unexceptional. In either case, you'll want to check whether your current brake calipers are compatible with rims this wide. For example, we were definitely pushing a set of current SRAM Force calipers to the extreme here.
Finally, there's the issue of long-term durability. While we didn't subject our test wheels to the multiple years of abuse most average users would hope to see out of these, the revamped rear hub design is certainly very encouraging. We wish we could say the same for the internal spoke nipples, though. Easton rightfully says that they yield a stronger rim given the smaller holes and better aerodynamics with the cleaner profile, but even small corrections unfortunately require you to remove at least a section of the tire – and if you glue your tubulars on correctly, this is no easy task.
While Easton acknowledged (and has apparently corrected) the bearing issue, the company stands firm by its decision to use internal nipples.
"The use of internal nipples was a conscious decision from our engineers due to the significant aerodynamic advantage tested in the wind tunnel," said Easton marketing coordinator Monica McCosh. "Additionally, carbon tubular wheels are generally used as race wheels, so giving up the serviceability of external nipples for improved aerodynamics is consistent with the product’s intended purpose. With the high tension spokes and very stiff carbon rim, these wheels should be extremely hard to put out of true and therefore the need to access the nipples should be an unlikely occurrence."
Unlikely, yes – and in fairness, we didn't need to true our set during testing. When and if truing is needed, however, doing so would be anything but a quick and painless process.
For more information, visit www.eastoncycling.com