Review: SRAM Eagle X01 Drivetrain

I hadn't yet started riding when our cassettes went from 7 to 8 cogs, but I doubt there was much controversy. The extra gear came with a switch to wider freehub bodies, so no parts needed to be any thinner, more fragile, or more precise.

But I did watch 9 speed happen, and I remember thinking it would be the beginning of the end. Chains and cogs had to be narrower, as did the margin of error because shifters needed to pull less cable per click. That was almost 20 years ago, and we survived. Now, after riding 12 speed for just six months, I've already begun to take it for granted.

SRAM's Eagle drivetrain is about more than just 1x11 with an extra ring. It's about the many innovations that make that extra ring possible, as well as a few more that refine the 1x experience, which some of us may not have noticed even needed refining. We covered all the nitty gritty nuts and bolts in our first look at the Eagle launch.

The common thread on those nuts and bolts is a dedication not just to longer life, but to maintaining peak performance throughout that longer life. Product longevity is a dying art in a society where we're expected to want a new phone, a new car, and yes, a new mountain bike every year. A few skeptics have even accused Eagle of simply being twelve more cogs in the consumerist machine. But after six months of abuse and hundreds of thousands of feet of elevation, my own Eagle drivetrain is in much better shape than my 6-month-old Samsung Galaxy.

And it had better be. At the X01 level, the cassette costs $360, and the chainring goes for $100. The unique shapes of the front ring's teeth were designed so that you'd be spending that $100 as seldom as possible. Extra material has been removed in the spots where 1x11 teeth were seen to be mushrooming over time. While the anodization has of course worn off my 34 tooth ring, the oddly shaped teeth still look nearly good as new.

The updated design also makes for smoother and quieter entry of the teeth into the chain. While I've never filed a noise complaint against a 1x11 chainring, noise means friction, friction means wear, and wear costs money.

The chain itself is also designed to limit the wear caused by the inevitable cross chaining that happens on 1x drivetrains. The links' perfectly rounded inner surfaces glide noticeably more smoothly onto and off of the high torque low gears, and after some hard use, my cassette still looks fresh. But I'm only just now ready to replace my first chain.

All the engineers in Germany can't make a gear that will survive long under a badly stretched chain, so it won't be until I've gone through a couple more preventative chain swaps that Eagle's true longevity will be tested. The important fact is that these past 10 months of the 12 speed drivetrain being out on the market have proven the concept.

But honestly, just riding it will prove the concept. I'm able to run a larger front ring and still have a lower low end than I had with 1x11 thanks to the no-longer-strange-looking 50 tooth ring. It's easy to mistake that big ring for a bailout gear. It's a different color and appears like a bigger jump than the rest of the cogs, which happen to match each of the gears in SRAM's 10-42 11 speed cassettes. But it quickly became just another gear to me.

Though it takes an 8 tooth jump compared to the 6 tooth below it, the gear ratio change from 42 to 50 is nearly identical to the one from 36 to 42. It also doesn't shift like a bailout gear. In fact, the Eagle derailleur shifts more smoothly than its predecessor throughout the entire cassette. The innovative chain gets some of the credit, and the derailleur gets the rest.

Its new Type 3 clutch is softer initially, so you're not fighting it as much on the downshifts. But Eagle's shift quality is just as susceptible to cable friction as any other drivetrain. This winter, the wettest in California's recorded history, claimed two lengths of cable and housing. But each time, after 15 bucks and 20 minutes, it would be good as new and ready to shred.

The elephant in the room here is that Eagle's introduction means that yet again, the ceiling on high end bike and component pricing has been raised. But the technology will eventually trickle down. Maybe not quickly enough or far enough for some, but it will. And most importantly, Eagle's long term durability is evidence that the people behind it know that it ain't cheap, and that we don't want to buy a new one every year.

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