What is it?
The X01 is SRAM’s less expensive follow-up to the wildly successful XX1 drivetrain which features 1×11 drivetrain and no front derailleur and 11 speeds in the rear.
X01 Derailleur – X-Horizon zero slant design, Type 2 clutch technology
Weight: 220 grams, $269 MSRP
X01 Crankset – Carbon arms with forged aluminum spider, 170 and 175mm lengths ,94 BCD, Bash guard option, 30, 32, 34, 36 or 38-tooth
Weight: 645 grams (5 grams heavier than XX1), $279 (GXP) and $319 (BB30) MSRP
XG-1195 Cassette – 11 speeds (10-12-14-16-18-21-24-28-32-36-42 teeth) , Hard plated with black surface treatment
Weight: 275 grams (15 grams heavier than XX1), $399 MSRP
X01 Trigger Shifter
91 grams, $139 MSRP
X01 Grip Shift – Rolling Thunder ball bearings, Lock-on grips included
143 grams, $129 MSRP
PC-XX1 Chain – 1×11 specific, Hard Chrome technology
Why you want it?
You want it because it is truly a revolutionary drivetrain for mountain biking. Just as drivetrains improved when they went from 3×10 to 2×10 a few years ago, this new 1×11 is an even more dramatic improvement. It not only works well, it is changing the face of drivetrains and even mountain bike design.
Front derailleurs never really worked well as the system was designed around a metal plate derailing a chain by pushing it from one side or the other. That meant that the chain had to be easy to derail with shorter teeth on the chainrings and the plates had to be placed close to each other to derail the chain from either side. This resulted in a chain that would fall all the time and a derailleur that would rub the chain often. Various systems were devised like chain guides, direct mounts and even electronic trim devices that would prevent rubbing automatically. All were an effort to fix a design that is inherently bad for mountain biking. Couple that with the fact that the system could not really shift between gears under full power loads.
So the elimination of the front derailleur in the SRAM X0 1×11 system has many benefits. But perhaps the biggest benefit of the SRAM X0 system is that the chain does not fall anymore. Since derailing the chain is no longer a requirement, SRAM devised an alternating narrow/wide chainring design that syncs up with the narrow/wide spacing of a chain. The result is a chain and chainring that mesh with each other. The chain does not lift from the chain and it thus stays in place even on the rockiest descents.
What are the downsides?
Cost is high as it only goes down to X0 level.
Gearing is not as low as 2×10. The lowest gear is 30 front, 42 rear and this can be a concern for heavier riders, high mountains or 29ers or heavier bikes. The XX1 has a smaller BCD (bolt pattern) and can take a 28-tooth front ring. The X01′s smallest allowed ring is 30 teeth. Use this Bike Gear Calculator to check how 1×11 gearing range compares to your current setup.
You need a new hub body called an ‘XD Driver Body’. Most newer hubs are compatible with this and the new body will accommodate the small 10-tooth ring. If your current wheel does not accept an XD Driver Body conversion, you will need a new wheel.
Is it a Revolution?
The transition to 2×10 was an evolution. But we think the arrival of 1×11 is a revolution and here’s why:
- Less chainslap and almost no dropped chains with no chain guide
- More useable gear range in the back means shifting is more seamless
- No gear duplication
- No chainsuck
- Noticeably lighter with less parts
- No front derailleur which is hard to adjust and doesn’t work that well
- More room on the bars, makes room under the bar for the dropper post
- Rider is always on the correct chainring in the front when on rolling terrain with steep walls
- On full suspension bikes, the front chainring can always be the right one for the suspension design as most suspensions are usually optimized for just one of the chainrings where they remain neutral under load
- It allows frame designers to shorten the chainstays when eliminating the front derailleur. This is key for 29er FS.
1×11 Poll Results
In a recent poll by Mtbr here, it’s obvious that experience so far with SRAM 1×11 drivetrains is very positive. 20% of respondents have tried it and think it’s the best drivetrain they’ve ever used. Another 52% have not tried it but are interested.
The X01 is every bit as good as the XX1 in terms of feel and functionality. It’s about 10% cheaper and a few grams heavier. But in a blind test, we would not be able to tell the two apart. So just like the XX1, we give the X01 our highest recommendation.
More info is available here: Complete Specs and Info on SRAM X0 1×11.