In this article I aim to give you some tips and product suggestions on how to build up a single front chainring 1X drivetrain (1×9, 1×10, 1×11) for your mountain bike. I hope to make this a simple journey by letting you know my personal selections for the best options and letting you decide which brands and parts would work best for you.
When it comes to mountain bikes these days it seems like everything is getting more complicated and technical. Have you seen the dizzying array of bottom bracket standards and headset choices available? How about trying to dial in fork and shock tuning?
While these new complications are often for the better, because they make our parts stronger, more adaptable, and often lighter weight, they can bog us down mentally and take some of the simple fun out of riding. This is where 1X or single chainring drivetrains come in. The concept isn’t totally new, but these days there are quite a few modern products that make running a single ring drivetrain a lot more easy to set up and ride efficiently.
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Why would I want to run a 1X Drivetrain?
- Lightweight – By getting rid of the front shifter, front derailleur, all of the cabling, and 1 or 2 chainrings you’re going to take quite a bit of weight off your bike. As a bonus this also declutters your handlebar a bit.
- Simple – Now you can focus on riding and only worrying about shifting your rear derailleur. You no longer have to fear bad chainring combinations and deciding which front ring is going to work best for the next section. This mental stress can get a bit fatiguing and now you can just focus on attacking the trail.
- Lower maintenance – Without the front derailleur and shifter this a few less components to have to adjust and maintain. You also get to save a bit of money by only replacing a single ring vs. a whole set when they wear out.
- More ground clearance – When setting up a 1X drivetrain you usually use a much smaller front chainring than a typical multi-chainring setup. This offers greater ground clearance allowing you to clear obstacles more easily.
- Quiet drivetrain – With the advent of clutch type rear derailleurs (SRAM Type 2 and Shimano Shadow Plus) chainslap is heavily minimized because the derailleur does not move as freely. The chain is also shorter and has more tension in a 1X drivetrain, which also helps on noise with riding over rough terrain.
What cassette should I run for my 1X Drivetrain?
Since you are only running a single front ring you’ll want to have the most range you can get in your cassette. Typical cassettes that a lot of riders use are 11/12T-34/36T but extended cassette ranges are coming out each model year. SRAM and Shimano both offer a wide range of modern cassettes in 9 to 11 speed models. Check out the cassette extenders at the bottom of this section for options to increase the range of your cassette up to 40T/42T with a special cog.
If you’re looking to buy a 9-speed cassette online I suggest checking out Jenson USA for the best selection and prices.
What options are available to expand the range of my cassette for 1X drivetrains?
There are several companies that are offering products to expand your cassette range to 40T/42T at the big cog. To do this you typically slide out your 17T cog and add in the new cog at the end of the stack. Some companies (OneUP) even provide a new 16T cog to replace your 15T and 17T cog for smoother shifting. Be sure to make sure the cassette expander cog you choose if made to be compatible with your cassette brand.
If you’re looking for options for a cassette expander cog for your cassette check out the prices and selection at JensonUSA first.
What size and type of rear derailleur do I need for a 1X drivetrain?
When looking at rear derailleurs you’re going to more than likely need a medium cage derailleur. Since you’re not shifting front chainrings, chain growth is not as much of an issue allowing you to run shorter chain lengths as well as using medium or even short cage derailleurs (if your chaingrings/cassette combo allows). Shorter derailleurs also have the side benefit of being more out of the way from rocks and other obstacles that can damage long cage derailleurs more easily. On cassettes with 42 tooth cogs I’d probably stick with a long or medium cage derailleur.
I would suggest looking at getting a clutch type derailleur if you can for a 1X drivetrain setup. These new style derailleurs called Type 2 by SRAM and Shadow Plus by Shimano don’t have the free play in the cage like older derailleurs. They keep tension on the chain much better, making it much harder to drop a chain. Since these derailleurs don’t shake up and down they don’t make hardly any noise, keeping the drivetrain quiet over rough conditions.
If you’re looking to buy a 9-speed rear derailleur online I suggest checking out Jenson USA for the best selection and prices.
How do you make your Shimano derailleur shift better with an extended cassette?
While having an extended range cassette offers a wide range of gear options to tackle varying terrain, shifting into these different gears can sometimes not be as smooth as you’re used to with a Shimano derailleur. Thankfully there are a couple of companies out there that are making some products to allow for better shifting performance and chain wrap.
OneUp RadR Derailleur Cage
OneUp has designed a new derailleur cage for Shimano Shadow Plus derailleurs that repositions the upper pulley to allow the derailleur to properly shift into the largest cog on an extended range cassette.
You can pick up the OneUp RadR derailleur cage online through JensonUSA.
Lindarets x Wolf Tooth GoatLink
The GoatLink is made in the USA and changes the mount point for your rear derailleur to improve shifting and chainwrap on 10-speed Shimano derailleurs paired with an extended cassette.
What size and type of chainring should I use?
Chainring technology and sizes have changed a lot with the advent of 1X drivetrains. Most riders are using single ring specific chainrings because they are often built more beefy and have different tooth profiles that are better at retaining a chain. The most advanced chainrings available are designed to be ran without a chainguide using a clutch type derailleur.
The critical piece of hardware in this decision will be your cranks. You’ll need to know your crankset BCD (Bolt Circle Diameter) by measuring it yourself or checking the specs with the manufacturer. If your cranks are a standard 104 BCD then you’ll have the most options available for chainrings. If you have SRAM cranks that have the splined interface (eg X9/X0/AKA/OE S1400/ OE S2210), or XTR M985 cranks with a 88 BCD you’ll have some other options.
Once you’ve ironed out the type of chainring that fits your cranks you’ll need to decide on a tooth count. Most riders feel something in the range of 30-32T is a good size for general trail riding. You can, however, find smaller sizes down in the 20’s that work with some cranksets. If you don’t do a lot of climbing a 32-38T chainring may be what you’re after.
- Wolf Tooth Components – These rings are made in the USA and designed to be used without a chainguide with a Type 2 or Shadow Plus rear derailleur
- 104mm BCD | 30-36T
- North Shore Billet – Chainring designed to work on SRAM splined cranks. Simply remove the spider and mount the chainring. These chainrings are made in Canada.
- SRAM spline | 27T-36T
- MRP – MRP makes rings for standard 4 bolt mount and SRAM spline mount. Their Bling Rings and Podium chainrings are made in the USA.
- 104mm BCD | 30-4oT
- SRAM spline | 28-36T
- *** BUYER BEWARE – Please Call HBC before buying products – Possible problems with this vendor have been reported – Homebrewed Components – These chainrings are made in the USA by Dan Wilcox. He makes these chainrings out of aluminum and titanium. Many of the chainrings can be made to fit 3/32″ chains or 1/8″ chains for a small upcharge.
- 102mm BCD (Shimano M960) | 31-36T
- 104mm BCD | 31-36T
- 88mm BCD (Shimano M985) | 28-36T
- Spiderless/Spline – Cannondale Hollowgram, FSA, Middleburn (X-Type and non-X-Type), Shimano M750/M950, SRAM splined, Bontrager Race X Lite Carbon, White Industries ENO | 28-36T
- RCR Fabrication – RCR is fairly new to making bicycle products but have had great reviews. These chainrings are also made in the USA.
- SRAM Spline | 32T or 34T
- Anderson Machines – The mounting for this chainring is a bit unconventional and you need to do a little bit of filing to your crankset. These chainrings are made in the USA.
- 104 BCD | 30T
- Blackspire – They make single speed/1X specific chainrings for a wide array of BCD’s.
- 104mm BCD | 32, 33, 34, 35, 36, 37, 38, 39T
- 94mm BCD | 30, 32, 34, 36, 38T
- 110mm BCD | 34, 36, 38T
- 102mm BCD | 32, 33, 34T
All of these companies also make great products with at least a 32T chainring:
You can pick up these chainrings online from JensonUSA. They have the best selection and prices on 1X chainrings.
Do I need a chainguide?
For most riders a chainguide of some sort is going to be a really good idea. As I mentioned, there are some chainrings being made that are designed to be ran without a chainguide. Personally I’d rather sacrifice a little weight to have the insurance that I’m not going to throw a chain hauling through a rough section of trail.
There are a lot of great single ring chainguides on the market. Most of these guides just guide the chain across the top of the chainring but some options offer more protection. How you want to mount your chainguide is going to be a decision you’ll need to make that fits your bike best. Options usually include bottom bracket mounts, seattube mounts, or even direct mounts on some newer frames.
- MRP – 1X, Lopes SL, AMG
- e.thirteen – XCX+
- Paul Components – Chain Keeper (made in the USA)
What type of chain do I need?
There isn’t really anything special to think about when buying a 1X drivetrain chain unless you’re going with SRAM XX1. You just need to make sure it is 9, 10, or 11 speed compatible with your cassette. Make sure you do fit your chain correctly. You’ll want to make sure the tension is set properly so you’re less likely to throw your chain due to being too loose.
- KMC X9SL
- Shimano HG73, HG93
- SRAM 971, 991
If you’re looking to buy a 9-speed chain online I suggest checking out Jenson USA for the best selection and prices.
- KMC X10SL
- Shimano HG74, HG94
- SRAM 1071, 1091
If you’re looking to buy a 10-speed chain online I suggest checking out Jenson USA for the best selection and prices.
- SRAM PC-XX1
- SRAM PC-1170
- KMC X11SL
- Shimano HG9000
- Shimano CN-6800
If you’re looking to buy a 11-speed chain online I suggest checking out Jenson USA for the best selection and prices.