The Basics to Upgrading the Rear Shock On Your Mountain Bike (Step by Step Guide) [Video]

Words by: Liam Woods

What Do You Need To Know When Upgrading Your Rear Shock?

Upgrading the suspension on your mountain bike is one of the best things you can do to breathe new life into your bike. Whether it is a fork or rear shock, you will be amazed at the technology these days in suspension, and how having a quality product gives you the confidence to shred harder than ever before. And let’s not forget to talk about the smile it can put on your face! When looking to upgrade the rear shock on your mountain bike, it may be overwhelming to know exactly what size shock you need, which kind of shock will fit on your bike, and also which shock will perform best on your specific bike. Here in this blog we are going to cover all of these questions and more.

Basics to Upgrading Your Rear Shock

Shock Sizing:

Mountain bike rear shocks come in an array of different sizes and recently made the switch from the older “traditional” sizing measured in inches (8.5 x 2.5) to the newer modern sizing that is measured in millimeters (210mm x 55mm), AKA metric. 

Basics to Upgrading Your Rear Shock

Now let’s break this down. A shock that measures 210 x 55 means that the shock is 210 millimeters long and uses a 55mm stroke. The length of the shock is measured from eyelet to eyelet, while the stroke of the shock is the amount the shock can physically compress. One thing to keep in mind here is that shocks that are the same eye to eye length may come with different stroke lengths. The most important thing is to make sure you get the correct length and stroke shock for your bike. It’s important to note that just because two different bikes have the same rear travel (150mm for example), doesn’t mean they always have the same stroke lengths. So what works for one bike might be very different on another bike. 

Basics to Upgrading Your Rear Shock

Along with shock sizing from eye to eye and stroke length, you also need to know your frame mounting width, which is normally sized by shock hardware. Shock hardware adds another element to getting the new rear shock installed on your bike. For a rear shock, you have to match up the top and bottom for the shock mounting hardware. There are no standards and every brand chooses what they think works best with their design. So what’s usually best is to either look at the brand’s website or contact the manufacturer to get the correct shock hardware. If you are upgrading your shock but with the same brand, you can often use the same shock hardware as long as it's not super beat up or worn out. So Fox shock to new Fox shock, you can use the same hardware, and same with RockShox or other brands. There is also a Trunnion style shock mount, which normally does not use hardware on the top, but bolts directly to the bike. That is a certain type of shock and while you do not need hardware up top, you do need to get a Trunnion style shock if that is what your bike is designed around. 

Basics to Upgrading Your Rear Shock

Each manufacturer and frame may use a different size shock and your bike is not guaranteed to function properly without using the correct size. To find out what size shock is correct for your mountain bike, either check the brand’s website for your model or call us at the shop and we will be more than happy to help!

Upgrade Options:

When upgrading your rear shock, one major question is whether to get a coil shock or an air shock. While there is no simple answer to this question, hopefully this information will make it a little more clear.

Basics to Upgrading Your Rear Shock

Left: Fox Float X2 (Air) Right: Fox Float DHX2 (Coil)

First, think about what kind of terrain you are riding and also what terrain your bike is intended for. The majority of trail bikes out there today come stock with an air shock because they are lightweight, offer a range of tuning options, and can provide an efficient pedaling platform. For those cross country focused riders, an air shock will certainly do the trick. For those riders looking for a bit more downhill performance, or maybe even racing an enduro race, you may consider a coil option. In general, coil shocks handle the small bumps on the trail with more ease, giving the rider supple feedback and more traction. The negatives to using a coil shock are that your bike now weighs a little extra and they tend to be a little more difficult to tune, especially if you don’t get your spring rate correct. 

It’s important to note that coil shocks tend to be more linear while air shocks provide a more progressive ramp up, so some bikes don't work well with coil shocks as you would bottom out very easily. So before you decide to get a coil shock, make sure it will work with your bike's suspension design. 

+ Please ask one of our professionals whether you and your bike would be better suited with a coil shock or an air shock.

There is also the question of what brand and model shock to choose. Most people know the two dominant brands Fox and RockShox. Both of those brands have a full range of options from cross country shocks to downhill shocks. Fox has their lineup with DPS, Float X, Float X2, Float DHX and Float DHX2. That list starts with cross country and goes to enduro and downhill shocks, with both air and coil mixed in there. From RockShox, starting with cross country through downhill, you have SidLuxe, Deluxe, SuperDeluxe Air and SuperDeluxe Coil

Basics to Upgrading Your Rear Shock

If you are looking for something a bit different other than the two big brands, there are a ton of cool small brands to look at. We carry Ohlins, DVO, Push Industries, Marzocchi, Cane Creek, and MRP. There are even more brands that we don't carry but we think are super cool like EXT, Intend, DT Swiss, more more! 


There are pretty much three different questions you need to ask about a rear shock before you buy: What size? What’s my preference? And is it compatible? Compatibility is a huge factor. It’s important to get the correct stroke, although there are certain instances where you may be interested in over stroking your shock. If you do this though, you’ll sometimes have clearance issues on smaller travel bikes, as well as depending on whether you’re using coil or air that we briefly touched on. 

Let’s dive a little deeper into the over stroke topic. When metric shocks came out I quickly realized that the small steps with the shock stroke would allow for lots of tuning and mods. For reference, a Yeti SB130 comes stock with a 210x52.5 rear shock, meaning there is 52.5mm of rear stroke. I wanted to see if I put on a shock with the same 210mm eye to eye but with a 55mm stroke if the frame would clear on bottom out causing frame on frame contact or tire on frame contact. I found out that Yeti was already making these small modifications in stroke length. They had something called the SB130 Lunch Ride where the rear shock is extended to the full 55mm stroke length. So the SB130 is a bike where the manufacturer has said you can change that stroke and not void the frame warranty. Other times you might be going against what the manufacturer recommends, so be careful and err on the more reserved side if looking to change your shock stroke. 

Basics to Upgrading Your Rear Shock

Left: RockShox Super Deluxe on a Santa Cruz, which is designed to take a coil but a tight fit. Right: Ohlins Coil on Specialized Demo that has very tight clearance to the frame

Moving into clearance issues, there are two clearances you should look for. One is the frame/shock clearance, which you might see a little more often with smaller travel bikes when you are looking to add a larger shock (i.e. moving from Fox DPS to Fox Float X). The piggyback reservoir might be a tight fit or not clear certain bikes. On some other bikes like the Santa Cruz Hightower and similar designs, the shock runs through the seat tube in a “tunnel” so there is a size max width. The Hightower does not allow for larger shocks like the Fox Float X, Cane Creek DBair or most coil shocks, so make sure your frame will clear a larger air can or piggyback shock if you are looking to upgrade your shock in that way. The other clearance to watch out for is simply making sure nothing hits. Normally if the seat stays have a brace, it could hit the seat tube if you over stroke the shock. Also to watch out for with over stroking the shock is the rear tire hitting the frame. On a Revel Rascal, for example, you cannot over stroke the shock as on bottom out the tire will hit the seat tube. You might think well it's only 2.5mm of stroke, and I have over 5mm of clearance, but the reality is that the 2.5mm of stroke is a ratio. For example, the bike has 130mm of rear travel with 52.5mm stroke, but when taking the shock stroke to 55mm the rear end gets about 136-137mm rear travel at the back wheel, making those clearance measurements hard to predict. So it's best to err on the safe side, or at the very least check with the manufacturer before going to a larger shock or a longer stroke. 

Coil versus Air, the forever topic that we here at Worldwide Cyclery still go back and forth about. Coil versus air is about half preference and half what your bike is designed around. We have a full blog going way into detail so we will keep it light here. If your bike does not work well with a coil shock, you are kinda stuck with an air shock. There’s also the fact that some suspension designs that have a yoke, shock extender or clevis put too much side load on a coil shock and are also not recommended. So if that is the case, it doesn't really matter about your preference since you are sticking with air. 

Basics to Upgrading Your Rear Shock

Left: Fox Float X (Air) Right: Fox DHX2 (Right)

Next is preference, and some riders definitely have one they like over the other. Coil gives a very smooth, very consistent feeling and once you ride coil and are not a weight-weenie or care about max pedaling efficiency, you might stick with coil. If you are jumping a lot or like a progressive suspension feeling, the air might be what you like. Like I said, we go back and forth, depending on riding style, trails, and season. Coil might be fun for six months then you suddenly want to jump back to air. If you are more of a straight line smash type of rider, you might have a preference for coil shocks more. The traction and small bump the rear shock gives you really cannot be beaten. If you like to jump around, take all the side hits, or ride a huge range of different trails the air shock might be more your style. Having the ability to add air pressure or add tokens to tune makes the air shock a more versatile tool. 

WWC favorite shock options:

Some of our favorite shocks come from brands like Fox, Rockshox, Marzocchi, Cane Creek, Push Industries, and DVO. While each has its advantages and disadvantages, finding a shock with good tunability and reliability will improve your riding experience on the trail. Personally, one of my favorites for a smaller travel bike is the new RockShox SidLuxe rear shock. For how small the shock is, its performance is insane, so smooth and works perfectly. If you’re looking for a bigger travel air shock, the Fox Float X2 and RockShox Super Deluxe are some top picks you will find on our bikes. And last but certainly not least is the Push Industries ElevenSix rear coil shock, tuned and made specifically for each model bike it goes on. It's a work of art that is also a top performing shock in its class. 

Basics to Upgrading Your Rear Shock

Words of Advice:

So when looking to upgrade your rear shock, there are so many things to consider and look at for rear shocks, from finding information to what feeling you want and how you would like your suspension to handle or change the way your bike rides. Below is a list of information you should look for and questions you should answer before looking to upgrade. 

  • Shock Size (eye to eye and stroke)
  • Hardware Size (top and bottom width and diameter)
  • Compatibility 
    • Stock stroke or over stroke
    • Clearance (frame clearance and over stroke clearance)
    • Bike designed for coil or air
  • Coil or Air shock (half bike design/half rider preference)
  • Brand and Desired Shock model

Remember to never hesitate to call us at the shop with any questions. We give recommendations on rear shock upgrades all the time! Mountain bikes are our passion and we love assisting our customers with anything cycling related. Feel free to send us a picture of your bike, use our live chat on our website or bring your bike into the shop. We are here to help! 


Liam Woods - Employee Spotlight
This article was written / authored by Liam Woods. Liam has been in the bicycle industry for over 10 years as a racer, professional mechanic, service manager and as of late, media and content creator. Liam has ridden thousands of different bikes, ridden countless components, tested endless MTB apparel of all kinds and written reviews on it all. He's a key piece to the Worldwide Cyclery "All Things MTB" content creation puzzle. He also makes consistent appearances on the Worldwide Cyclery YouTube channel and Instagram.


If you are one strange human that would like to read a transcript of the video above, continue reading below!

Ladies and gentlemen three years ago we made a video about how to upgrade the rear shock on your mountain bike and it is very old at this point and we are back to make a revised version and hopefully demystify the confusing world of how to upgrade the rear shock on your mountain bike this video will have four chapters which you can see somewhere and you can bounce around between them if one is more relevant to you than the other they are step one figuring out what size shock is currently on your bike sort out your upgrade options and then common misconceptions and rare compatibility issues as well as final thoughts and words of advice so let's do it [Music] are you ready to talk about chapter one me well like together we're doing it oh yeah yeah yeah yeah okay perfect

The first thing you need to figure out when you want a new rear shock on your mountain bike is what size you have currently on your existing bike that is slightly complicated but the number one thing eye to eye. eye to eye basically means eyelet to eyelet the distance between that uh we do actually have a blog article about how to measure this stuff with more graphics and visuals on all these things that we mentioned link down below in the video description but eye to eye and stroke. stroke is going to be right here or it's probably easier to see on this shock right here there is a ton of different eye to eyes and strokes and every bike uses a different one for various different reasons so don't make any assumptions that this is simple in any way shape or form eye to eye stroke length two very key things you need to figure out and measure on your own bike you can either measure it yourself or you can go to the manufacturer of your bike's website and hopefully figure out what size is on there which might be there yeah so a lot of manufacturers do actually list the shock size on their website and some like to keep it a mystery for some reason i guess we'll never know the other part is the mount type so there are a few different mounting styles this is kind of the more common traditional mount type on this shock right here standard mount you've got trunnion mount where your shock bolts are going to thread directly into the air can so there is standard mount there's trunnion mounts there's some other oblong strange mounts on rare bikes but yeah we'll get into that later in the rare compatibility issues but basically your eye to eye your stroke and your mount type are the three key things you gotta know and then your mount type mounting hardware as well you need to measure that and figure out what size is on there so then you know what mounting hardware because you very very likely are going to need new mounting hardware with your new shock to make sure that it fits correctly that's right unless you're replacing your shock with the same brand yeah then you can probably keep your same hardware you can reuse that stuff yeah but hardware is fairly cheap anyway so it's always good to just replace it especially if your old chalk is clapped out you might as well get some fresh hardware when you get a new shock unless it's out of stock unless it's out of stock yeah that's a good point [Music] gonna be a little buzz maybe but we'll see you so we weren't drinking very much tonight you've been pouring all sorts of whiskey no you said that that's right so now that you know what psi shock is actually on your bike that's going to basically determine what you can upgrade to because there's only so many shocks available in a particular size and now you have to think what do i get uh the first thing you might be wondering is coil versus air there is a lot of youtube videos and articles already on that we made one as well which you can find below in the video description um what do you think coil versus air what are your thoughts i think coil versus air really depends on what kind of bike you have kind of riding you're doing and really like what kind of you know feel you're looking for when you're upgrading your bike if you want something super plush and compliant you probably want to go with coil if you want something super mega adjustable and lighter weight then you probably want to go with an air shock yeah one of the huge differences is weight uh air shocks are always going to be lighter than coil shocks kind of no matter what but there is some suppleness and cool factor to coil shocks that you might not get with air shocks which is also debatable because as the years have gone by every brand that makes air shocks is just perpetually trying to make them perform amazing and by amazing it's like they're trying to make an air shock perform like the best of coil shocks yeah like the new fox float x2 is probably a good yep example of that and same with the new floyd x that's right yeah it's pretty cool so this is a rabbit hole to think of what you need coil versus air is the first thing to determine we will go into a little bit about coil incompatibility in the next chapter of this video but coil versus air is something to consider then you want to think okay if you're going to upgrade your shock what are you missing why do you want to upgrade to begin with are you lacking an adjustment you really want does your existing shock only have rebound and you really want some type of compression adjustment do you really want some type of lockout because you feel like your shock is bobbing and you want a remote lockout on your handlebar so there's various things you might want in a new rear shock and that's what should lead your decision on what to upgrade to so what are you missing what are you really craving that you think would make your bike work better or just an adjustment or a feature that you really want in that rear shock that you don't currently have that should sort of be your guiding light on on what to get right couldn't have put it better myself yeah brands fox and rock shock are the two 800 pound gorillas in the bike industry when it comes to suspension and they make rear shocks and forks for basically everything then there's some boutique brands which you ride yourself you have a push industries rear shock push industries 11.6 yeah which is a very very premium coil shock custom tuned per rider per bike it's amazing yeah i mean absolutely 100 it also costs a ridiculously large amount of money so factor that in there's dvo there's cane creek there's various other rear shock brands out there that are sort of smaller more boutique brands that offer just different various features and adjustments and cool factor so yeah it is a rabbit hole to figure out what you want to upgrade to but again think of what you're missing and what you're craving that your current shock doesn't have and let that be your guiding light of researching what you want and now that you know hopefully what size you have that eliminates some of your options as well so it narrows it down that's right so there we go next chapter [Music]

Common misconceptions and rare compatibility issues this is this is an extensive topic that could probably be an hour long video it could be a whole video it could be a whole video um jared deals with this a lot now because he does live customer support all the time here at worldwide cyclery and deals with customers that are calling in and emailing in and chatting and asking various things like over stroking let's talk about that one is a common misconception that's right so a lot of people think you know oh i got the eye to eye matched up and you know maybe i can just get a little bit longer of a stroke shock to fit in there get a little more travel out of my bike well let me tell you that is not a good idea unless the manufacturer specifically says you can do it uh because well there's a chance you could really mess up your bike if you do that yeah yeah cause you you will notice if there's certain eye to eyes that are offered in two different stroke options or maybe even more and you'll then hear this have this thought in your head or maybe find it on some forums and it's like oh i could just get this eye to eye but a longer stroke than what's on my bike now and i'd have more travel right and that seems really cool until you put it on your bike and you hit a jump and the rear wheel of your bike slams into the back of your seat tube and breaks your wheel breaks your frame and you go over the bars and you realize holy [ __ ] that was a terrible idea

Over shocking or over stroking is a slippery slope of danger slippery so proceed cautiously or just don't proceed at all right yeah and chances are if you are trying to do it and nobody else has done it before there's a chance that you probably shouldn't do it so you're telling me there's a chance there's definitely a chance yeah i did that when i was a young buck i think i was 17 i had a da vinci troy and i over stroked that bike and there was a brace on the chainstay above the rear tire and i overstroked it and it actually whacked into the back of the seat tube when i bottomed out and dented the frame and then therefore my my bike's kind of ruined it's like i can't warranty it it's i can't really sell it your warranty is voided it's it's don't over shock or over stroke just proceed extremely cautiously when it comes to that one so that's one common misconception and a thing to just be wary of the other thing is clearance issues right that's right clearance issues so you probably have a bike that came with a shock on it and you want to upgrade it but there could be a chance that the shock you want isn't going to fit on your frame there's certain things like for example if your bike came with an inline shock doesn't have a piggyback reservoir and you're like oh i really want this shock that has a piggyback reservoir for x y and z reason but then you bottom out and this thing slams into your carbon seat tube and you're really unhappy about it so that's another rare compatibility issue and again proceed with caution talk to someone who's an expert like us or the manufacturer of the bike and ask them about those things see if anyone's done it see if it's possible coil shocks too obviously you can tell the diameter here is very different so this just might not fit on your bike um if it was designed around an air shock and a coil shocks might not work so yeah that's right especially if you have a short travel bike with that's uh you know designed more for a bike or a shock that doesn't have a piggyback then chances are you're probably not gonna be able to put a coil shock on there just by the nature of the design of the bike so yeah something to look out for yep and speaking of air and coil there's another issue when it comes to coils so coil inherently is much more linear that means it kind of has that same compression feel all the way through the stroke whereas air you can tune that very differently you can make it linear you could actually make it regressive and you can make it progressive and certain bikes will be designed around a specific shock being is it a linear shock or regressive shock a progressive shock and the manufacturer will actually design and tune a shock specifically for that bike and it could be something where it's a really linear frame but the manufacturer of that bike wants it to actually have a progressive ramp up like you'd want and they'll custom tune an air shock with a very progressive feel to it and if you just throw any old coil shock on there even if it fits it might be so linear and that bike is already naturally linear or regressive that it kind of ruins the feel of the bike and the bike now just doesn't behave the suspension doesn't behave the way the manufacturer intended so going down a rabbit hole of complexity it's going to blow through your travel basically yeah right so just be careful of that it's another one of those things to worry about that's actually where companies like push industries are really interesting and cool because they're making custom tuned coil shocks per bike and then per rider weight right that's right yeah and your writing style yeah and your riding style and preferences so that's something where you couldn't necessarily just buy any old aftermarket coil shock but you could buy a push industries one that was designed specifically around that frame and they finagled all the things inside of here which we don't even want to dive into to make it tuned correctly so that bike behaves the way the manufacturer intended it to or maybe better hopefully better or better compared in your preferences in your eyes that's right so i don't know is that all the rare compatibility issues you can think of off the top of my head i think so yeah hopefully that didn't just make you sweat all over profusely i know i am yeah [Music] what are what are did you turn it on or no okay well turn it off

final thoughts and words of advice advice our final thoughts are our proceed cautiously upgrading the rear shock on your mountain bike is very complicated there are terms and conditions to this agreement that you must agree to it's complicated it's a bit of a rabbit hole there's a lot of youtube videos a lot of things you can read don't just trust everyone in the forums that says oh you can put this shock on or this shock's the best cause it's just more complicated than that and there's no simple solution to it kind of like a lot of things in the mountain bike industry and life yeah and life in general um so proceed cautiously a word of advice from us is contact a professional um we answer phone calls and emails and chats all day every day about rear shock upgrades and fork upgrades and we have mountain bike nerds on staff all day that can help you figure out what shock you have and all of the things we just told you we can just kind of hold your hand through that right can you hold people's hand rear shock upgrade obviously you're not really supposed to hold the hands right now but i will do my best yeah from six feet away i will virtually hold your hand virtually hold your hand to help you figure out what shock you have on your bike which one you should get and then purchase it that's right if it's in stock that's right maybe because it is 2021. but maybe you're watching this 2022 it is in stock that's right place like us a high-end mountain bike specialty retailer that does upgrades all the time we can help you the manufacturer of your frame should also be able to help you if you contact the company that made your bike there should be staff there and they work there and for example yeti right all the guys at yeti are always messing around with various different shocks and tunes and adjustments and they're all just crazy mountain bikers so they're introverted can't say that for every brand but typically if you contact the brand of the bike that you have they should also be able to steer you in the right direction of what fits what might be a great upgrade what's good all of that sort of stuff or someone like us we'd be happy to help too so if you don't want to try and do this all yourself then uh yeah just ask we will do all the heavy lifting for you ask for directions don't be that guy yes ask for directions before you get lost yeah exactly or if you're or if you get lost for five minutes then ask not five hours like what most guys do yeah [Laughter] thank you very much for watching we appreciate it please share this video with your mountain bike friends or anyone you know that needs to upgrade their rear shock and is lost in the world of confusion and it happens oh and thank you thank you for watching and we love you thank you we love you!

May 06, 2021

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