Though some may question the logic of using carbon fiber for mountain bike wheels, the latest generation of plastic wheels combine light weight, stiffness, and durability in a way that aluminum wheels simply can’t. The but, however, comes at the cash register: carbon fiber wheels are pricey. Easily twice the price of their alloy-rim’d stablemates, the cost has been awfully hard for most riders to justify.
In order to bring the experience gained from building the all-mountain Haven Carbon wheelset to a wider audience, for 2013 Easton have released the EC70 Trail model. Forgoing the UST compatibility provided by the Haven’s solid inner wall and turnbuckle nipples has reduced the EC70s’ cost, while the updated M1 hubs promise to have left earlier versions’ bearing and freehub durability issues behind. Armored Ballistic Composite has been replaced with EC70-level carbon fiber, reducing impact resistance somewhat, and the rims have narrowed somewhat.
What’s left is a 1,355g wheelset (1,420g once taped) designed for both race and trail use. The price? A still-dear $1,800- about 30% less than the Havens. But are they any better than a 1,400g alloy wheelset? Hit the jump to find out!
In a word, yes. We’d like to preempt any but I could build a 1,350g Stan’s wheelset for $X… comments by saying that there’s no way that any aluminum-rim’d wheel in this weight range would be holding up as well as the EC70s have been. 
We too would love to believe that we could build a flyweight aluminum wheelset, slap it on a 6in trail bike, and ride that bike as intended. In fact, we’ve tried. And the results haven’t been pretty. Dented rims, wobbly wheels, unacceptable flex, or all of the above have all been the results. For an XC race bike in kinder environments, sure. But despite a head start measured in decades aluminum wheels in this weight range simply can’t take the abuse of day in, day out trail or all-mountain use.
The EA70s, on the other hand, are holding up just fine. Mounted to our 150mm BMC Trailfox, the hand built and acoustically trued Eastons have spent 6 months on New Mexico’s rock-strewn trails, mowed down nearly 70 miles of Arizona’s Black Canyon singletrack, and rolled and dropped the best that Grand Junction and Fruita have to offer. There hasn’t been a peep or a wiggle from the hubs and the rims are as true as they come. 
In fact, the bearings were so smooth after 5 months that we couldn’t being ourselves to knock them out to install the recent (free) upgrade kit.
The EC70s arrive with all of the necessary adapters to run the front wheel as a 15mm thru axle or quick release and the back as a 135mm QR, 135x12mm thru axle, or 142x12mm thru axle. Over the past month, $93 XX1-compatible freehubs have also become available and their installation is quick and easy. As mentioned above, our hubs have been smooth and trouble-free. As a bonus, they’re pleasantly quiet: somewhere between American Classic and DT Swiss or Stan’s on the low end of racket scale.
What does not come in the box is anything to make the wheels tubeless. This seems like a major oversight on Easton’s part as few riders in this price range have any interest in running tubes. A bit of experimenting found 2 layers of Gorilla Tape (as used by Enve and others) and Stan’s universal valve stems to be the ticket. Once seated, they’re fine- but we can’t help but think that a bead seat tweak would help to make installing tires on the EC70 Trails as easy as it is on most other wheels. 
As they stand, an air compressor really is needed to get everything in place.
So who are the EC70s for? Their combination of light weight and solidity makes them a great match for the Trailfox: a 6in bike that can be ridden on anything from a lift-assisted descending day to a backcountry epic. The 20mm rims are a bit narrower than many riders prefer- but by tucking the sidewalls in a bit seem to have spared us from some of our usual sidewall cuts. Again, we’d love to see the bead seat further developed- but once installed we haven’t had any issues that weren’t caused by operator error. Beyond trail riders, bigger racers would be a natural fit for the EC70s- benefitting from the wheels’ combination of light weight and solidity.
Despite their mid-level EC70 tag, their price tag makes the Eastons a premium product. In the sub-$2K range, the EC70 Trails are stouter than Roval’s Control Trail SL ($1,650 / 1,280g) and their 29er version is lighter than either Reynolds’ 29er Carbon ($1,990 / 1,555g) or Roval’s Control Carbon 29 ($1,200 / 1,590g). For those who can both afford and justify the cost and are patient with initial setup, the EC70 Trails would be a great choice for a lightweight ‘quiver killer.’
marc
