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Easton EC90 Cranks

January 28, 2009
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Easton is one of the most trusted name in cycling composites, so the EC90 carbon fiber crankset attracts our attention for its surprising light weight (664 grams, including bottom bracket assembly), and also because we know from experience that Easton would not have released it if the crankset did not pass the most stringent testing standards. Except for aluminum inserts at the pedal threads, and where the arms engage the tubular chromoly bottom bracket axle, the EC90 crank arms and spider are full carbon composite construction. Easton’s suggested retail for the EC90 crankset is $699.

TECH
Easton uses a number of tricks to build the EC90 cranks. The arms have a rigid foam core that allows Easton to use a high-pressure molding process. Microscopic carbon nanotubes are used to fill the spaces between the fibers in the crank’s carbon matrix. The crank is molded using strips of unidirectional carbon ‘confetti,’ which gives the structure omnidirectional strength, similar to an aluminum forging.

The chromoly steel crank axle uses Easton’s ‘Taper-Wall’ construction. The tube walls are thicker where the crankarms attach and notably thinner in the center. The left-side crank arm clamps to the splined axle in the same manner as Shimano Dura-Ace, and bearing end-play is adjusted with a threaded end-cap in the manner of a threadless headset. The external bottom bracket is available with ceramic hybrid bearings (100 grams) or stainless steel (105 grams).

Easton breaks tradition with a wrap-around flange near the clamping area on the left arm that gives it a bulky look, but probably adds stiffness. Aluminum, Torx-drive chainwheel fixing hardware is a nice touch, and the proper wrench is included with the crankset. The standard chainrings (53, 39) use a 110-millimeter bolt circle, on a five-arm spider. Easton uses both machined shifting gates and stainless steel pins to assist the front derailleur, and the aluminum chainrings are hard anodized and Teflon coated to minimize wear and friction.

RBA SAYS
We replaced a SRAM Red compact crankset with the EA90 and it was an easy installation. The EA90 system moved the chainline outward one millimeter, which made running the cross-chain position (big ring to large cog) noisier than it should be. Shifting was crisp in both directions, especially up to the big chainring, which was quiet and very positive regardless of where the chain originated from on the cassette sprockets. We didn’t have test riders on staff powerful enough to flex the Easton crank arms, but we did give them all we had and can happily report that the EA90 crankset can best or equal SRAM, Campagnolo or Shimano in rigidity, and matches the shifting performance of all but the ’09 Dura-Ace.

Easton successfully offers up an alternative carbon fiber upgrade to anyone who is riding a first or second-tier crankset from the big three and is interested in a significant weight reduction (30 grams in our case). A compact crank is probably on the way, but until then, anyone who wants to ride a sub-600-gram carbon crankset from Easton will have to man up to a 53×39-tooth gear selection to experience its pro-level performance.

PRICE: $699
CONTACT: www.eastonbike.com

WEIGHT: 664-grams, including bottom bracket assembly
BONUS POINTS: Stiff with good power transfer and light, light, light.

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