SRAM Debuts X01

Single-Ring Drivetrains Grow a Bit More Affordable & Gain Greater Foothold

By Vernon Felton

Last year, SRAM strode onto the scene and raised a ruckus when they unveiled XX1--a component group that made single-ring drivetrains feasible for riders who didn't possess Hemi-level legs, while also promising to rid the world of dropped chains and mis-shifting rear derailleurs. Today, SRAM announced the release of a more wallet-friendly single-ring group, X01, which sells for roughly $200 less than SRAM's top-tier XX1 kit yet boasts the same core features.

What sets X01 apart from its slightly pricier sibling? Why should you even care when you've probably spent years shifting a front derailleur and never thought, "Man, what I need right now is some way to just rid myself of that thing that makes climbing hills easy!"

Fair questions. Here are some answers. We'll start with the basics on X01 and move onto the larger discussion of why any of this actually matters.

All the core features of XX1 are embedded in this new X01 group:

*Single chainring (five different sizes) with alternating wide-narrow teeth;
*A chain designed to mesh perfectly with the chainring's alternating teeth;
*11-speed trigger (or GripShift) rear shifter;
* X0-level "X-Horizon" clutch-equipped rear derailleur;
*SRAM's XD driver body; &
*A gargantuan (10-by-42 tooth), 11-speed cassette.

There aren't in fact, a whole lot of obvious distinctions between XX1 and X01. The marketing literature notes that the X01 crankset now features a chainring guard option, which is a plus for anyone who rides technical terrain. Interestingly, absent from the X01 mix is the 28-tooth chainring that is an option in XX1. Finally, the published weights for core components (the crank, cassette, etc.) seem to be within a few grams of one another.

Given the great similarity between the two component groups, it's not surprising that X01's price tag looks a lot like XX1's. In total, you're looking at about a $200 savings, which isn't likely to land an X01 group in every home's pot, but anything that brings us a step closer to that scenario is welcome news all the same.

XX1 hit the market last year with a sticker price of $1449.00 The new X01 group isn't far behind.

That's the question that needs asking.

Well, at the expense of sounding like a sold-out stooge, there are actually a host of benefits that crop up when you move to a single-ring drivetrain.

The most obvious is simplicity. Ditching the front derailleur and its accompanying shifter helps reduce complexity.

"Handlebars are starting to look like airplane cockpits," explains Race Face marketing and warranty man, Rob Bohncke. "You have dropper-post triggers, lock-outs for your fork and rear's just becoming cluttered and complicated. Single-ring drivetrains help simplify your controls--that's a good thing."

While SRAM isn't touting weight savings as the key benefit to going "one by,” you can clearly dump some grams from your rig by killing the shifter and front derailleur attached to it. It's just simple math.

Fewer Dropped Chains
One of the greater benefits of SRAM's 1X drivetrain is that it nearly eliminates dropped chains. Chain retention gets a boost via SRAM's "TYPE 2" clutch-equipped rear derailleur and the patent-pending wide-narrow-wide-narrow tooth profile on SRAM's chainrings that meshes with SRAM's specialized 11-speed chain.

Stronger Chains
Since the XX1 and X01 chain no longer needs to be pushed and shoved from chainring to chainring, it can also be made burlier. SRAM claims that the XX1 chain is nearly four times more wear resistant than its 10-speed chain.

As with XX1, you can run the new X01 group with either SRAM's 11-speed trigger shifter or GripShift unit. What you won't find is a shifter for that left hand of yours.


When people talk about the benefits of ditching the front derailleur, they tend to focus on how it might benefit them on their current bike. That makes sense, but it misses a larger point: killing the front derailleur has the potential to improve the effectiveness of future full-suspension frame designs.

Engineers hate the front derailleur. In addition to being the most sluggardly of components on our bikes, it also takes up a ton of crucial real estate on a frame. The front derailleur sticks out there like a sore thumb that's begging to be smashed by increasingly-fat rear tires, complicated linkages and the like.

"About 70 percent of the time that we spend designing a typical frame is spent dealing with front derailleur clearance. That's pretty brutal," explains Dave Weagle.

I gleaned that quote from Weagle a year ago, when I was asking engineers from every corner of the industry about the difficulty of designing long-travel 29ers. Each and every designer pinpointed the front derailleur as one of their biggest headaches.

In a nutshell, a lot of bikes (particularly 29ers) have long chainstays and suffer from tractor-trailer handling because of that damn front derailleur. Chainstay-mounted derailleurs and shorter 2X front derailleurs have helped ease the pain, but taking the front derailleur out of the mix entirely? That's going to allow engineers to build some truly kick ass bikes in the future.

The Trance Advanced SX is just one 2014 model that will wear SRAM's new X01 kit.

"One-by from a design perspective, allows us to control the wheelbase much better--the rear end in particular," says Kevin Dana, Giant Bicycles' global off-road category manager, who has equipped a large number of Giant's 2014 Trance 27.5 models with single-ring drivetrains.

"Front derailleur clearance is always critical," continues Dana, "especially when we get into trail bikes with really wide tries, you have chain guides in some cases, linkages to work around on dual-suspension bikes and you want to keep the rear end short so the bike is fun to ride...just think about how much stuff is going on in really just one area of the bicycle--it's hard to accommodate it all. One-by really opens it up. It makes my job as a designer a lot easier. We still accommodate front derailleurs on our bikes, but we are definitely looking to the future and are hoping that the front derailleur will just go away one day."

At nearly $400, the X01 cassette ain't cheap, but it is also key to getting that low gear range out of a single-ring system.

SRAM, of course, isn't the first company to suggest that single-ring drivetrains might make sense for riders outside of the gravity set. What SRAM brought to the table, however, was a complete single-ring system (chain, rear derailleur, cassette and crankset) that worked together to create a more durable, trouble free version of the 1X systems that a minority of riders were already pummeling.

The addition of SRAM's monster cassette (with its 42-tooth granny gear) is what opened up 1X to riders who didn't possess super-human levels of climbing fitness. Kudos to SRAM on that score. Of course, once they did all that, enterprising riders who didn't have a spare grand and a half stinking up their wallets asked themselves if there was a way to get some of those same benefits without blowing a huge wad of cash on a new drivetrain.

The answer: sorta.

Race Face, MRP and a host of other companies are offering chainrings that they claim bring at least part of the XX1 and, now, X01's benefits. You can pair one of their chainrings with a clutch derailleur (Shimano or SRAM) and a typical 10-speed cassette, and wind up with a simpler system and better chain retention than you can expect from a drivetrain with multiple chainrings. Sure, if you want that lower gear range, you still need to pony up a serious wad of cash for SRAM goodies, but the point here is that you don't necessarily need to buy the entire kit to glean some of the benefits promised by XX1 and X01. You won’t, of course, glean the entire range of benefits SRAM offers (and, by the way, the SRAM stuff shifts amazingly well) but, then again, your bank account may not allow you to go whole hog on new parts.

Race Face is just one company offering new single-rings aimed at the growing market. Those narrow-wide alternating teeth look a lot like SRAM's patent pending design, but Race Face contends that an existing (and expired) patent covered the basic design.

Back in March of 2013, Race Face debuted a “Narrow-Wide” chainring of their own that is compatible with 9, 10 and 11-speed drivetrains. In a nutshell, the new 104 BCD Race Face single rings feature an alternating narrow/wide tooth profile that they claim leads to less dropped chains and which, at first glance, looks a hell of a lot like SRAM's X-SYNC chainring.

SRAM clearly thinks the Race Face ring looks suspiciously like its own, because it has "invited" Race Face and other companies to license its patent-pending chainring design. Race Face, for its part, is having none of it, arguing instead that its design is based on an expired patent that was originally filed in 1978 (Patent 4174642 “Chain Drive Including Sprocket Having Alternate Wide And Narrow Teeth”).

“We purposefully designed our narrow-wide tooth pattern off of that expired patent,” explains Race Face representative, Rob Bohncke. “to avoid any cross issues with SRAM’s XX1 patent. They are definitely different designs. SRAM has a taller tooth profile than we do and a different shape overall.”

“As we started to hear the whispers of XX1 coming down the pike, we started to get our wheels turning to try do something similar and that’s when our engineers found this patent. This was about a year and a half ago. Sales are really good–they’re flying out the door. It’s hard to keep them in stock, to be honest. Putting our ring onto a regular 104 crank–whether you have 9, 10 or 11 speeds–makes it pretty easy to get into the one-by game.”

And how does the addition of only the chainring affect chain retention?

“It’s a huge difference. Obviously, nothing is ever 100 percent–the Narrow-Wide ring doesn’t eliminate dropped chains entirely, but we were testing it for three to four months before we ever even hinted that we’d come out with it and I’d say that we hardly ever dropped chains in any situation. I ran it with an older non-clutch style derailleur and I think I had only one chain drop during four months of riding through really harsh, winter conditions over really rough tracks that would have sent the chain flying off of any other ring. It’s a big improvement.”

Will you, the consumer, start seeing these rings from SRAM competitors included as original equipment on production bikes?

“Right now with one-by drivetrains, there are a lot of options out there--aside from SRAM,” says Giant’s Kevin Dana. “What remains to be seen is how compatible they all will be with one another and with existing drivetrains. As a bike builder, we need to make sure that the products we're delivering to consumers are backed by the manufacturers and that we aren't going to have any shifting or chain problems. So for now, we're sticking by our proven partner, SRAM, for those one-by options for 1×11. Now, having said that, you will see our Trance SX aluminum model, sporting a 1×10 system with a Shimano Zee crank. There are a lot of shop guys and consumers out there running 1×10. That's been a popular option for people who can't afford the SRAM option yet. We're delivering that bike as a way to get that reliable, simple drivetrain solution into the hands of the most riders. That's our goal at the end of the day.”

SRAM's dedicated 11-speed chain is said to be four times more wear resistant than a typical 10-speed chain. Again, that's a perk of the SRAM system you won't find elsewhere.

While it’s too early to wave goodbye to the humble front derailleur, it’s clear that single-ring drivetrains are extending beyond the gravity set and, in a few years time, will come with a price tag that won’t raise your accountant’s eyebrows. For now, the price of wrangling a dedicated “one by” group is still steep, though if you want all the benefits of going single-ring, it’s still the only way to go.

Can’t afford to go whole hog? We hear you. Fortunately, you have options and that’s only going to get better in the near future. Count on it.