It’s no secret that great parts are hard to review- and Shimano’s XTs have long been among the best day in, day out cranks on the market. For the past several generations, the arms, rings, and bearings at the center of Shimano’s do-it-all group have drawn on the company’s greatest strengths- while the latest generation’s 10 speed compatibility and double- or triple-ring options bring them bang up to date. The crank arms are hollow forged from aluminum: a stiff, light (just under 860g including BSA BB), and durable construction method. The 24-32-42 chainrings are built of steel, aluminum, and composite in order to balance weight with durability. Finally, Shimano’s tortured-looking chainring teeth, ramps, and pins are designed to provide shifting performance that approaches XTR- for a fraction of the cost. That’s the sales floor pitch: how have the latest XTs performed on the trail and race course? Hit the jump to find out!
In short, there are no surprises when it comes to the FC-M780s. Their performance is excellent all around. Over nine months of 24-hour racing, trail riding, and backcountry epics, they’ve generated only positive thoughts- when I’ve thought about them at all.
The 24mm steel spindle and wide (but not cartoonish) arms make for a plenty-stiff pedaling platform, and the rings themselves are impressively solid as well. While some of the big ring’s teeth have suffered from being bashed into rocks and logs, the ring itself has stayed straight and a few seconds with a Leatherman can snap off any teeth too badly deformed to carry on. 
Similarly, the aluminum arm ends are deeply scratched- but those gouges aren’t the concern that they might be with carbon fiber.
The DynaSys (ten speed) chainrings have played well with both our 10s Project 24.2 race bike and an older 9s trail bike. The 24t lowest cog yields an ever-so-slightly taller low gear when paired with a 36t cog than a 22×34 would- but it’s not missed on anything but the steepest and longest climbs (and remains worlds better than a double when winching up 12,000′ passes).
On the race course, I found that I actually prefer the triple to Shimano’s doubles. While the double arguably shifts better, it requires more front shifting as I run out of gears at one end of the cassette or the other. Sure, the granny is essentially along for the ride and a 1×10 would be lighter- but that 32t chainring is just about ideal for most courses. Of course, the available double (FC-M785) exists for those who would prefer it, with very similar construction and performance.
If past experience is any indication, Shimano’s XT chainrings will last longer than anything else on the market (ours aren’t thinking about pausing, let alone stopping). When the time comes, the standard 104/64 bolt circle diameter will make finding replacements or fitting a bashguard easy. The black finish on our samples is showing the effects of constant rubbing from my duck-like feet- something that would be less of an issue with the available silver finish. Performing nearly as well for less than half the price of an XTR triple, the $320 XTs are hard to argue with. There are a lot of good cranksets on the market, but none I’ve ridden approach the FC-M780s’ stiffness, shifting, and durability without costing significantly more.
marc
