Words by: Max Morgan
In this episode of our How To series, we are going to walk you through changing and installing a Sram direct mount chain ring on your SRAM crankset in eight easy steps. What makes any chain ring considered direct mount is in this case when the one-piece chainring bolts directly on to the crank arm. A more traditional chain ring would use four or five bolts to secure the ring to a crank "spider" that is then attached to the crank arm. A direct mount chain ring simplifies things creating a strong and robust system that is easier to maintain and most of time lighter as well. Just like with any traditional chain ring, there will be times where you will need to change your direct mount chain ring either because it is completely worn or because you might prefer a different size. We will talk you through these eight easy steps to installing your Sram direct mount chain ring.
The tools needed for this job are relatively basic. For starters, we will need a good set of hex keys. We will need an 8mm hex key to remove and install the crankset and also a 2mm hex key to fine-tune the preload adjuster. When it comes time to remove, install, or change your Sram direct mount chain ring, you will need a T25 torx. If you are missing the right tool for the job, check out our full collection of tools to work on your bike. I will be using a set of Wera Hex Plus L-keys, a Wera T25 Torx L-key, a Park Tool TW-5.2 Torque Wrench, and a T25 bit socket.
Sram offers a large variety of chain rings manufactured from different materials, designed with 0mm, 3mm, and 6mm offsets for different chainlines, and of course sold in different tooth count sizes. In this demonstration, we will be working on a Sram XX1 Eagle AXS crankset that is paired with a Sram X-Sync 2 SL Direct Mount Chain Ring.
Before we can get to removing and swapping out our Sram direct mount chain ring, we will have to remove the crankset. To do so, we will first move the upper slider on the chain guide out of the way and remove the chain from the chain ring. The bike we are working on today is using a OneUp Components Top Chain Guide V2, and using a 4mm hex key, we can adjust the chain guide slider so it is out of the way of the chain and chainring. Use the Cage Lock feature on your Sram derailleur if possible, pull the chain off the chain ring without breaking the chain, and set it on to the chainstay out of the way. This will all make way to remove the crankset in step two.
Once the chain and chain guide are out of the way, take an 8mm hex key and remove the drive side crank arm. Remember that most Sram cranks are torqued to 54 N*m and you will need more leverage than your typical multi tool. Continue to loosen the 8mm bolt to back the crank arm off of the crank spindle.
Having the drive side crank arm off is also a great time to remove the non drive side crank arm so that it can be cleaned and re-greased before being installed again.
Once you pull the cranks off of the bike, you will see that there are three bolts holding the chain ring on to the back side of the drive side crank arm. The unique pattern that mates the crank arm and chain ring together is what keeps the ring from spinning or slipping when you put out all that power. The three bolts on the back of the crank arm are there to keep the chain ring from backing off of the spline pattern. The back of the chain ring is a good place for dirt and grime to hide, so wipe everything clean so you can remove the chain ring bolts in step four.
Using a T25 torx, remove the three chain ring bolts from the back of the crank arm. Once you have removed each of the three bolts, the chain ring should slide off of the crank arm nice and easy. The chain ring bolts are not torqued super super tight, but you will need more than a screwdriver handle to remove them. I am using an L-key here, but having something like a Park Tool AWS-7 three way will also do the trick.
Having the chain ring pulled off of the crank arm is the best time make sure everything nice and clean. If you are putting on a new chain ring, hopefully that should already be clean and ready to go. With the crank arm itself, wipe clean any old grease, dirt, and grime around the splined pattern. When everything is off the bike and here, you might as well take advantage and get everything like new.
Before installing your new chain ring, apply a very thin layer of grease on the splined pattern on the back of the crank arm. This can help prevent the crankset from doing any kind of creaking later down the road. Before sliding the new chain ring in to place, notice that it can only be fitted in one specific orientation. Slide the chain ring in to place and make sure it is seated all the way up against the back of the crank arm. Start by threading in each of the three chain ring bolts with a T25 torx key. Written on the back of the chain ring you will find the torque spec for the chain ring bolts; 8-9 N*m or 71-80 in-lbs. I will be using a Park Tool TW-5.2 adjustable toque wrench with a T25 bit socket to torque these bolts to spec. 8-9 N*m isn't abnormally tight, and so if you aren't using a torque wrench, there is no need to try to over tighten these bolts.
Before installing the crankset back through the bottom bracket and on to the bike, it's important to apply a layer of grease on the crank spindle and on to the inside of the bottom bracket. This grease will prevent moisture and debris from getting in to the bottom bracket and will keep the cranks spinning more smoothly for longer.
For a more thorough breakdown, check out our step by step article How To: Installing Sram Eagle DUB Crankset and Bottom Bracket. Using a 2mm hex key, loosen the pre load adjuster and turn it away from the + direction. Slide the non-drive side crank arm and crank spindle through the bottom bracket. Line up the drive side crank arm and tighten the cranks down from the drive side with an 8mm hex key. The crankset should be torqued to 54 N*m. Put the chain back on to the chain ring and slide the chain guide back in to place. Remember that if you are changing the size of your chain ring, you may also need to modify the length of your chain.
This article was written / authored by Max Morgan. Max has been a professional downhill mountain bike racer for the last 10 years, competing in the UCI World Cup downhill series and U.S. Pro GRT series. Having ridden all different kinds of bikes on trails all over the world, Max's experiences being out on the circuit give him a unique perspective on what makes for a quality cycling component. Max also has degrees in Mechanical Engineering and Physics, and so if you don't see out on the trail, chances are he is probably in the garage tinkering on the next project.