2015 SRAM X01 DH 7-Speed Drivetrain
Intended Use: DH Racing
Components:
- 10-24 XG-795 Mini Block Cassette
- 7 Speed X01 DH X-HORIZON Rear Derailleur
- X01 DH X-Sync Crankset
- PC-XX1 Hard Chrome chain
- X01 DH X-Actuation 7 Speed Trigger Shifter
Blister’s Measured Weight: 1,465 grams
MSRP: $1,097.95
Reviewer: 5’9” 155 lbs.
Duration of Test: 1.5 Months
Mounted to: 2015 Canfield Jedi
Test Location: Whitefish, Montana; Whistler, BC
It’s no secret that most of the reviewers at Blister are pretty psyched on SRAM’s 1×11 drivetrains. Even SRAM’s lower-priced options like the new GX group perform very well.
The X01 DH kit takes those attributes and puts them in a tidy little package for DH riders and racers, with the option to run either 7 or 10 gears.
And the question is: Does SRAM’s X01 DH live up to the standard set by its less gravity-oriented siblings?
Who’s It For?
Before I go any further: yes, this kit is pretty dang expensive. And yes, guys have been piecing together small gear clusters on DH bikes for years that are generally less expensive, and often yield entirely acceptable results. This kit isn’t really aimed at these tinkerers, nor is it aimed at people who are on a tight budget.
This drivetrain is primarily aimed at those looking for the best-of-the-best specialized DH drivetrain. But beyond that, this kit could also be the first stepping stone in an incremental roll out.
When XX1 first came out, lots of people scoffed at the price. And while XX1 is still an expensive proposition, SRAM has introduced increasingly affordable options.
The X01 DH kit hasn’t been around for all that long, and we’ll have to wait to see if more affordable options become available. But in the meantime, I’m not going to knock it purely because it’s expensive.
The Build
There are two iterations of the X01 DH group: a 7-speed version, and a 10-speed version. I rode the 7-speed version, and I’ll talk about some of the less obvious differences between the two.
My build kit included the 7-speed shifter, derailleur, and cassette, 165mm 34t crankset, and 11 speed chain. Here’s a more detailed breakdown of the build:
Rear Derailleur: $276.99, 260 grams
The kit incorporates a SRAM X-Horizon rear derailleur, which is essentially the same design used in most of SRAM’s 1×11 groups. Most notably, this design separates the “vertical” component of the derailleur’s movement from the “horizontal” movement. In a practical sense, this means that when you hit a bump and the derailleur gets jostled, it won’t ghost shift into the next easiest gear.
This was an occasional problem with Shimano derailleurs and older SRAM derailleurs, and many people have probably experienced the rear derailleur clunking around a little bit while pedaling through rough terrain. The X-Horizon design doesn’t have these problems, and I almost never had an issue with it skipping, even when pedaling through rough terrain.
The 10-speed version of the derailleur is essentially the same, but features a slightly different cable pull ratio (so the 7-speed derailleur isn’t compatible with a 10/11 speed shifter, or vice-versa).
Both the 7- and the 10-speed versions come in two cage length options—if your bike’s rear suspension has a lot of chainstay growth, you might need the longer cage.
Both versions also have the same roller bearing clutch found on many of SRAM’s other derailleurs.
Cassette: $302.99, 134 grams
Like the 11-speed XX1 cassette, the 7-speed “Mini Block” cassette is machined out of a single piece of aluminum, with a spoke guard pinned to the inside position.
I’ll say the same thing I said about the XX1 11-speed cassette: to anyone who appreciates some nice machining, these things are really cool.
They’re also really light. At 134 grams, the 7-speed cassette weighs less than half as much as the mid-level 10-speed Shimano cassette that I was running previously, and it’s lighter than the lightest road cassettes that SRAM makes. Generally speaking, the XD drivers required for the X01 cassettes are also a little bit lighter.
Functionally, the cassette is also a bit different than the standard road cassette you’ll find on most DH bikes, in that, even though it has fewer cogs, it actually offers an almost identical range of gearing.
Now let’s talk numbers:
A fairly common setup on modern DH bikes is a 38t chainring paired with a 10-speed, 11-26 cassette.
In terms of gear inches (the standard unit for bicycle gearing measurement) on a 27.5” wheeled bike, this yields a range of 55.2 gear inches, which is the difference between 95.8 gear inches in the 38/11 combo, and 40.6 in the 38/26 combo.
With the 7-speed X01 kit, you can actually achieve the same range—and get similar gearing—using a 34t chainring. The result is 94.4 gear inches in the 34/10 combo, and 39.4 in the 34/24 combo for a range of 55 gear inches and net sacrifice of a miniscule .2 gear inches.
Here’s a graph of those numbers. Notice that the gear range is very similar between the two examples, but the X01 DH kit covers that range using fewer gears, and uses a smaller chainring to do so:
This has two real world ramifications. First, you can run a smaller chainring, which means you gain a bit more clearance. Just using an MRP guide as an example, the ability to run a 34t ring means you can run their “mini” guide instead of their “mega” version, and the skid plate protrudes a bit less.
Second, having the same gear range but with fewer cogs means that there are bigger jumps between gears. For bikes that you pedal uphill a bunch, this is bad; it makes it hard to fine tune your cadence. On a DH bike, however, this is a good thing.
When you’re hammering on the pedals and clicking through the gears to keep up with your acceleration, this means less shifting to get into the harder gear that you’re looking for. The same goes for when there’s a sudden rise and you need to get into an easier gear really quickly. Precise cadence matters much less, and quickly, efficiently getting into the right gear matters a whole lot more on a DH bike.
The 10-speed version of the X01 DH kit misses out on pretty much all of these cool features, since it just uses one of SRAM’s standard road cassettes.
The flip side, of course, is that it’s far more affordable (and it’s cross compatible with other systems, which the 7-speed version isn’t).
Shifter: $142.99, 122 grams
The 7-speed shifter is essentially just a revised version of a standard, 11-speed X01 shifter, and that’s a good thing.
I like the ergonomics of it, and the downshift paddle’s position can be adjusted. Like all of SRAM’s current higher end shifters, it’s matchmaker compatible.
It isn’t quite as light as the XX1 shifter in terms of lever action, but it’s not bad at all, and it gives a very positive “click” for each shift—same as the 11 speed iteration of the X01 shifter.
Cranks: $314.99, 697 grams (165mm length, including 34T direct mount ring and 83mm bottom bracket)
The X01 DH cranks are pretty similar to SRAM’s carbon DH cranks that have been out for a little while now, but now they’re available with a direct mount ring, which shaves a bit of weight.
Like previous iterations, they have the extra material over the carbon XC cranks that SRAM offers, and this version now includes a narrow/wide chainring.
A spider is still available for the cranks, so if you’re inclined to bolt up your ring in the traditional manner, you can do so.
The cranks are the same for the 7- and 10-speed versions of the X01 DH, and they come in the usual assortment of configurations in terms of length and bottom bracket compatibility.
The version I rode was 165mm length with an 83mm threaded bottom bracket, and a direct mount 34t X-Sync (narrow/wide) chainring.
Chain: $56.99, 252 grams (114 links)
I used a standard SRAM 11-speed chain (mine is a XX1 chain that has hollow pins). I’ve not had any issues with these chains, either with this kit or with any other 11-speed setups.
NEXT: Performance, Durability, Etc.