Easton EC90 XC 29 Wheels - Review

Carbon Fiber Rims

At 1,433 grams, Easton claims that the EC90 XC 29 wheels are the lightest UST 29er option on the market, a point that's largely due to their carbon fiber rims. These aren't just any catalog-order carbon fiber rims, though, with the company saying that they're actually employing proprietary ingredients to manufacture their 'Armoured Ballistic Composite' (ABC) rims in Taiwan. I'm told that the ABC material is similar to what the military employs for lightweight body armour and some ballistic applications, with the idea being that if it is resilient enough for the military to use, it's probably tough enough for us to bounce them off some rocks and roots.




So what is ABC? Easton says that they employ exclusive yarns and laminate structures, along with ''MRES-class resin formulation involving rubberizing and other impact-resistant components,'' that allows them to use 15 - 20 percent less resin than if they went with a more conventional approach, but still end up with a finished product that's extremely strong. They also use high-modulus polyethylene rather than Kevlar for a high strength to weight ratio, which is supposed to be ideal in situations that require resistance to ballistic and blast impacts. Their words, not mine, and while I don't suspect that most us need to be concerned over how our rims will hold up to gunfire, it's not far fetched to assume that a material designed to withstand bullets could also shrug off some pointy rocks and misjudged line choices.

The final product is 19mm wide internally (24mm externally), which makes them better suited to tires less than 2.3" wide in order to avoid excess casing roll, and they sport a sealed UST rim shape that allows you to set them up tubeless without fussing about with rim tape. This is possible due to Easton's patented double-threaded nipples that turn into inserts in the rim's outer face, thereby allowing Easton to forgo having to mould or drill holes in the rim bed to provide access to the nipples. The carbon rim's UST designation doesn't just denote a sealed rim bed, though, as the rim must also conform to the UST standard that includes both a specifically shaped bead hook and humps on either side that help to lock the tire in place. Companies that use the UST design say that it makes for a much more secure, and therefore safer, tire and rim combination.


Easton's Latest Hubs

Easton has a bit of a spotted past when it comes to their hubs, but they say their latest design has sorted out the bearing life issues that have plagued the company's otherwise impressive wheels. The all-black hubs no longer offer the ability for the rider to adjust bearing tension, which is probably a good thing when you consider that many people were likely over-tightening them, which then drastically reduced bearing life. Instead, there's a much simpler design that only requires that you tighten the rear axle to 10 Nm. The job does require a large wrench and a 12mm hex key, though, the latter of which most people probably won't have kicking about in the bottom of their toolbox, although it's not a task that should need to be done more often than doing your taxes. The axle also has lefthand threads to keep it from undoing itself when you're riding, much like how the drive-side threads of a traditional bottom bracket are lefthand threaded for the same reason.

Both the front and rear hubs spin on sealed bearings, as you'd expect, and the freehub body employs a traditional three-pawl design that everyone will be familiar with, and it engages with a thirty tooth drive-ring inside the hub shell to provide twelve degrees between engagement points. Replaceable hub end-caps allow the front to fit either 15mm thru-axles or forks with quick-release lowers (remember those?), while the rear hub can do both 12 x 142mm axles or 135mm quick-release setups. No Boost option at this point in time, though.





On The Trail

I mounted up two different sets of tires on the EC90 XC 29s - a set of 2.25" wide Vittoria Barzos, and some Racing Ralphs from Schwalbe - all of which went on quickly and easily without spraying sealant or making me throw any tools across the shop. Setup is made even more painless by the sealed UST rim bed saving you from having to wrap the rim with tubeless tape, which isn't exactly a hard job to do, but it is one less thing to have to think about. I flatted a few months ago while using a different wheelset because the tubeless rim tape actually tore for some reason, but this won't ever be an issue with the EC90 XC 29s.

If you've never had the opportunity to ride a set of wheels that barely weigh more than a single dual-ply downhill tire does, you're missing out. You literally feel fitter and like you've just mainlined a triple dose of caffeine, especially if the EC90 XC 29s are replacing something more run of the mill like the 1,800 grams wheels that were previously on my bike. The result was faster acceleration and higher speeds all around, and I'm not just talking about them feeling faster - my times up my local ascents all tumbled after installing Easton's flyweight wheels. The stopwatch doesn't lie, but it shouldn't really come as a surprise given that I dropped nearly a full pound of rotating weight, which is the most important mass when you consider that we use our meager horsepower to get our wheels spinning in the first place.




As far as rigidity goes, the EC90 XC 29s feel adequate relative to burlier cross-country wheelsets out there, despite having only twenty four spokes per wheel and weighing very little. I come in at around 165lb and probably ride above my skill level on occasion, but I never felt like the wheels were flexing an excessive amount. In fact, I'd argue that they feel better on the trail than a set of wider ENVEs or XTR wheels, and although that's a subjective thing to say, the best way to describe the difference is that some of the competition can make you feel like there's a few extra PSI in your tires, whereas the EC90 XC 29s have a touch more forgiving nature to them. This is a good thing, especially on a short-travel bike. I wouldn't call them flexible, though, as these are pure cross-country wheels and they're more than laterally rigid enough for that task.

There's no arguing that the 19mm internal width of the Easton carbon rim will seem excessively slim to some, especially as even cross-country rims are tending to go wider and wider these days, and it makes the EC90 XC 29s and whatever tires you end up running a bit sensitive to air pressure. I had some noticeable casing roll and sealant bleeding out at the bead, even when running the 2.25" wide Barzos in the mid-twenties, with the blame falling on the 19mm rim width rather than the tires themselves (I had no issues with the Barzos on wider rims). Adding just a few PSI put an end to this, but the 19mm width means that they're not best suited to wide tires or low pressures.


Reliability

Bearing life is still up to par, with both the front and rear wheels spinning smoothly after months of use. Anyone who's used Easton's wheels from a few years ago might be surprised by this fact, but the company has obviously made some improvements on this front. There was something odd going on with the rear wheel's axle, though, with there being a smidge of bearing play, or at least something that felt a lot like bearing play, that refused to go away regardless of how tight I did the axle and end-cap up. Easton says to tighten the axle to a very snug 10 Nm, which is 88 inlb (disc rotor bolts are often torqued to 55 inlb), but the small amount of knocking at the hub never went away despite any amount of force applied. Sure, the play only added up to maybe a millimeter or two at the rim, but I'd bet that anyone who just shelled out $2,200 USD would be bummed by it. Easton did say that this would be covered by their warranty program, though.

The 1,433 gram weight of the EC90 XC 29 wheels suggests that they probably aren't the best choice if you measure your ride enjoyment in time spent airborne, but having said that, they held up relatively well to the sort of abuse and neglect one usually tends to only dishes out when they simply get to hand the product back and walk away from any repair bills - the only upkeep being a single truing session for the rear wheel. It wasn't out by much, but it was enough that I wanted to stay on top of it before it got worse, which it never did after setting it straight in the truing stand. I'd say this is acceptable for such a light wheelset that was treated pretty roughly.



Pinkbike’s Take:

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Reviews and Tech Reviews Wheels Easton