17 June 2009

bikefix Exclusive Review: Shimano Deore XT (M770) crankset

While flash, sexy parts may be exciting and attract envious glances at the trailhead, there is a lot to be said for the unglamorous workhorses that just plain work well. Ride after ride, these parts perform their intended function with minimal complaint. Not necessarily inexpensive, their long and uncomplicated years of service can make them a bargain in the long run. Much of Shimano's Deore XT group fits this description to a T. While the flagship XTR group gets all of the attention, and other companies' offerings have more carbon fiber cachet, in my experience, nothing seems to work better while requiring less attention than the original mountain bike group.

While there are quite a few who complain about the large bearings' unloaded seal drag and yet another bottom bracket standard, its hard to argue with Shimano's Hollowtech II system. By moving the bearings outboard of the bottom bracket, the company made room for massive spindles supported on oversized bearings, spaced as widely apart as possible. The system is stiff, light, and durable. Coming the from short-lived bearings that were a characteristic of the ISIS standard and broken spindles that marked the square taper standard before that, Hollowtech II was a great use of divergent thinking to address common problems. Sure, bottom bracket shells had to be better prepared than in the past, some of the early bearing seals were pretty awful and the Q-factor (lateral distance between pedals) grew a bit- but given the alternatives, the choice was clear.

The M770 crankset is Shimano's second generation Hollowtech II XT crankset. This particular crankset has been on my all-day XC bike for the past two years with virtually no complaints. The bottom bracket still spins smoothly, the chainrings hold torque and shift well. When I installed the M770s, I had a look at my old (previous generation XT) crankset's big ring and thought that I'd try to wring another season out of the old one before installing the 'ring that was provided. Two years on, the now five year old Shimano XT big ring is still going strong. Sure, its missing a few teeth, ground down and broken off by rocks and logs, but its still straight and works just fine and has earned its keep. Some day, when things go horribly wrong, there's a new XT ring on the wall in the garage, waiting and ready to go.

Buying an XTR equipped bike about a year ago, I pilfered most of the parts for my favorite bike before selling it on (it rode terribly). For a time, I was seduced by the sexy gunmetal XTR crankset and ran it on my main ride. While those with perfectly dialed front shifting (there has to be someone out there), there might be improved shifting. I, for one, couldn't feel a difference, and the 70g weight savings was outweighed by a resale value high enough to fund a new brakeset and the need for XTR-specific tools. The fancy cranks went and the XTs stayed.

Priced similarly to aftermarket options from Race Face and TruVativ, Shimano's Deore XT crankset isn't as rare or sexy but a prize nonetheless. The company's SLX crankset is also attracting a lot of attention down the bike shop, and saves $75 in exchange for an extra 45g, a bit less spent on the rings and a stouter bottom bracket axle. Given my XT set's flawless performance, I can't see much point in recommending trying anything but. Not cheap, but undoubtedly the safest crankset bet for one can make for $315.


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