Shocks and Struts: The "Quick" Guide
The main components of your suspension that keep your vehicle from slamming into the ground or flying into the air with every bump or pothole you hit: your shocks and struts are essential to your truck or Jeep’s driving ability.
They can affect everything from turning and handling to the roughness of the ride and whether or not your kids in the backseat are going to get super car sick on long rides. In other words, whether you are an off-road racer or just a highway cruiser, your shocks and struts are integral to the way your vehicle drives.
Before I got super into aftermarket parts, particularly suspensions, I knew kind of what shocks and struts did, but I didn’t honestly know the difference. If you’d put say a picture of both in front of me, I probably wouldn’t be able to tell you which is which.
For instance, there’s a set of Shocks and Struts from Rancho, one of our best selling manufacturers, I might add at the top of this post as the feature image.
And again, before I got into aftermarket, I might have thought the springy ones were the shocks. But it turns out, it’s the other way around. The parts with the black springs are the struts. We’ll be covering those in depth below. But first we are going to tackle the shocks, in depth!
Most vehicles have either a strut or shock at each wheel, but not both. For many stock vehicles on the road today, there will be a strut for the front suspension and shocks on the rear.
We’ll start with the shocks.
Shocks "Quick" Guide
Shocks come in many different varieties, and while I will touch on the old school to the new hotness, the majority of what we carry is the Mono-Tube Gas Pressure Shock Absorbers, just so you know up front. First, some definitions.
What is a shock absorber?
And why do some people call them dampeners?
Shock absorbers or dampeners slow down or reduce the bounce from your springs (including your struts) when your vehicle moves up and down over bumps in the road. These shock absorbers take kinetic energy (up and down motion) and convert them into friction and heat. This prevents your vehicle from bottoming out or tilting too far forward when braking or leaning too far back during rapid acceleration.
Shocks History Lesson
The Old School
Some of the first shock absorbers in the automotive industry were pure hydraulic, meaning they were tubes willed with hydraulic oil. Using a piston that would move up and down in the oil, these tubes would slow down the movement by the shear viscosity and friction of the oil.
Only a few problems here: well, at least one: oil doesn’t have summer high friction. So that’s a thing. It can only absorb so much shock, in other words. Secondly, when the oil started to get heated up from all that up and down motion, the air molecules in the oil would separate, causing what those in the know call cavitation (it looks like foam, so you can call it foaming). As the air molecules break free, your old school shock absorber would lose about a third of its ability to reduce vibration. The only way to return it back to 100% would be to let it sit for a while without moving. This was highly inefficient and annoying.
In the 1950’s, techs at Bilstein, a high performance aftermarket suspension company, figured out that by using compressed gas, specifically Nitrogen, they could prevent this foaming and increase the ability of the shock to absorb energy and vibration. The Gas Pressure Shock Absorber was born. And the modern era of shocks came into existence almost immediately.
For it was at this same time that the twin-tube shock was about to come up against another major Bilstein innovation.
Twin-Tube Shocks Dominate Until...
Up until the 1950’s, the majority of shocks on the market were twin-tube shocks. This meant that they were true hydraulic shocks. The oil from the main tube or Pressure tube would be compressed down into the Reserve cylinder which was part of the second or twin tube. This would amplify the force of the compression, but it also created a secondary shell of protection against piston damage.
At the time, this technology seemed to be the best possible. And then with the introduction of the Gas Pressure Shock Absorber, by Bilstein, came another whooper: the Mono-Tube.
Mono-Tube Shocks Enter the Scene
With the advent of gas pressure shocks, came the Mono-Tube. Instead of having two tubes in which the oil could be compressed, Bilstein developed a single tube separated by a seal. On the one side of the seal was the hydraulic oil and the piston. On the other, they put the Nitrogen gas. The seal would float in between, allowing for pressure changes to occur. This lead to huge gains in shock absorbing performance. Pure hydraulic oil shocks were phased out over time due to the increased abilities of the gas pressure shock. Mono-tubes too began to dominate in the aftermarket community, especially for racing, both off and on road.
Today shock absorbers still come in a variety of styles and upgrades. In general, pure hydraulic oil only shocks are obsolete, though you might find one in an older stock vehicle still on the road.
Today, nearly every shock on the market is gas pressured. This allows for a faster and firmer ride, and in general has been accepted as the new industry standard.
However, the Twin-Tube shock is still around. Today’s choices in aftermarket shocks then are still multifaceted. Here’s everything you need to consider when purchasing new shocks.
What kinds of shocks are there today?
- What are the main variants in shocks now?
- Number of Tubes: Mono Vs. Twin
- Remote Reservoir Options
- Whether or not the shock is adjustable or tunable
Mono Vs. Twin Tube
The biggest consideration should be whether you want to go with a Mono-Tube or a Twin-Tube. While many aftermarket experts claim to be divided on this still, I’ve gotta tell you that Mono-Tubes in general are almost always superior. If you are looking for a true performance grade shock, I would stick with Mono-Tubes.
If you just want to replace your stock shock absorbers with something similar, then likely you should stick with a Twin-Tube. Now I say that because most OEM shocks these days are Twin-Tube. So you should double check what you have, and if you like the way your vehicle rides, stick with the Twin-Tube.
Chances are if you are lifting your truck or Jeep at any extreme amounts, you’ll need to go with a Mono-Tube. Mono tubes are able to be installed at more extreme angles than Twins. But that’s not the main reason to go Mono.
The biggest reason is Aeration. With a Twin-Tube shock, the Nitrogen and Oil aren’t actually separated by any seal. They are compressed and will stay separated naturally until things start heating up and bouncing around. So even with the best twin-tube shocks on the market, there are good chances that over time the Nitrogen gas will get mixed in with the Oil. This will reduce performance somewhat and can lead to a bumpier ride after the shocks have heated up.
Now this might not happen for some time, but eventually with a Twin-Tube shock this is likely to occur. Since in a Mono-Tube Shock the Nitrogen and Oil are kept separate by a seal, you don’t really have to worry about the gas mixing with the oil. Hence, you will get a more consistent ride out of a Mono-Tube Shock.
Mono-Tubes also have a better heat dissipation and tend to displace a larger volume of oil / gas, so they have a better ride for those reasons too. I’ll explain the science behind all of this below, if you’re into nerdy science explanations.
The only possible downside to a Mono-Tube might be that some experts suggest that Twin-Tube shocks last longer. But after crunching the numbers myself, I would have to ponder this. Unless if that seal between the oil and gas is leaking on a Mono-Tube, I would have to think that they would both last about the same amount of time or the Mono should last longer. The reason has to do with the Hydraulic Principle, which you can read about below.
Here’s the reason why I think most experts seem to suggest that Twin-Tube shocks last longer: people who install Mono-Tube shocks tend to drive harder. What I mean by this is those of us in the aftermarket community tend to do more off-roading and racing and just driving over rough terrain than those who aren’t into aftermarket accessories. So you might be able to find someone who drove their stock sedan with stock twin-tube shocks for a long, long time before they failed. I have no doubt of this. But if those same Twin-Tube shocks were to be subjected to the same kind of punishment was a Mono-Tube, my scientific understanding of these shocks suggests that the Twin-Tube would fail substantially sooner than the Mono. But don’t take my word for it, see the numbers and the science behind this all below.
Other things you should consider before purchasing:
If your truck or Jeep is lifted, make sure you get shocks that will fit it. Most of the shocks will say if they are for stock height, plus 2 inches, etc. So just make sure you are getting the right fitment for your ride.
You should consider whether or not you want a Reservoir too.
Shock Remote Reservoirs tend to come in two different styles: Piggyback and Detached. These Reservoirs contain additional Nitrogen and Oil in them to be mixed in with the rest as the shock heats up. These reservoirs aid then in dispersing heat and keeping the shock at optimal performance. The two styles of reservoirs really just have to do with where they are mounted. A Piggyback Reservoir attaches to the actually shock itself. This probably is a perfectly find place for it, unless if say you want to add some springs and go for a coilover. But that’s another topic, isn’t it? A Detached Reservoir is connected to the main shock by a high pressure tube. And the Reservoir itself can be mounted a number of areas. This style has become highly popular because it gives you a lot of options. Often times you can mount this within your wheel well or on another part of your suspension or you could even Piggyback it. Hence, Detached (since they too can often be Piggybacked) have become pretty standard in the Reservoir style.
One of the newest innovations in shocks these days are adjustables. These shock absorbers come with typically a little manual knob that is either on the shock itself or attached to a reservoir. The knob allows you to tweak the stiffness or rigidity of the shock up or down some in order to tune the dampener to the exact setting you prefer.
These are still pretty new on the scene, and whereas I initially thought they might just be a fad, there might be something to these bad boys. Fox currently has an offering like this as well as Koni. But the most expansive adjustments we have seen so far come from Rancho.
Rancho’s Tri-Tube RS9000XL Series
While I am on the fence concerning the whole Tri-Tube thing, Rancho has figured out how to adjust their Tri-Tube RS9000XL shocks to upwards of 9 different settings. This provides upwards of 400% difference from the 1 setting to the 9. That’s a pretty substantial shift in shock absorber.
Why am I pressing this? Many of us when we decide to dive into upgrading our suspensions are more concerned about lift kits than shocks. But you’re gonna need some new shocks and struts after you put on that lift kit. With that in mind though, most of us don’t even know what it is like to drive around on really good shocks.
Rancho has figured out a way to let you test out various settings with one pair of shocks. That’s kinda brilliant. Of course, other companies have adjustables too. I’m just highlighting them because that’s a high level of adjustment without adding a Reservoir on. Also, look at their sweet pics and videos (I’ve used many of their pictures in this guide and even some screen grabs from their YouTube). Very nice work, Rancho. It is no wonder you are one of our best sellers.
I’ve always been a Bilstein fan, but I’m also very much into Fox Racing. So if you’re looking for my personal opinion on the top three shocks on the market today: there they are.
Choosing the Right Shock for You
At the end of the day, selecting an aftermarket shock has a lot to do with how you drive and what you want your ride to feel like.
If you like the more OEM feel of your original shocks, maybe you’ll want to stick with some Twin-Tube shocks. We’ve got offerings from Daystar and Rancho to cover you there.
If you’re an off-roading kind of guy who likes to hit the trail or even go race an off-road course, then you’ll want to go with some Mono-Tube shocks. Check out all of the Fox 2.0 series options or some Bilstein 5100 series. Rancho’s RS7000MT are great for trucks and Jeeps too.
Still ambivalent? Just can’t make up your mind? Not sure what your style is? Why not try a pair of adjustable shocks. A Fox Performance 2.0 Reservoir with the Dual Speed Compression Adjuster upgrade will give you 10 separate low-speed options and 12 high speed compression levels. Talk about customization! Don’t want a Reservoir added on? Try out that Rancho RS9000XL Tri-Tube and let us know how you like it and what setting you’ve been driving it on.
Ready to Order your New Shocks?
With that, we hope now you’re ready to order your new pair of shocks. Do not you should always buy and install shocks in pairs. Just wanted to make sure that was clear.
When you’re ready to buy, we hope you’ll pick up your shocks here at Midwest Aftermarket, especially if you enjoyed or found our guide useful. Our collection of shocks, struts, truck running boards, and much more includes all the leading styles and brands. Midwest Aftermarket is the #1 online retailer for aftermarket truck and Jeep accessories, selling products at the lowest prices and providing the best customer service in the industry. With the goal to provide the highest quality product with the fastest shipping at affordable prices, look no further for your vehicle’s aftermarket accessories. From UTV’s to Jeep-fanatics to F150’s or Chevy Silverado’s, Midwest Aftermarket will give you the customer support you deserve.
Still want more guide? Read on for the Science behind Shocks! Want to learn more about Struts instead? Our Quick Guide to Struts will follow the science stuff below. Enjoy!
The Science Behind the Shock
So while we’ve managed to explain the ride feel and basic functions of a shock, we haven’t actually explained any of the science, particularly the physics, behind what makes them work. I realize that not everyone is a major nerd like me, so if you just want to know the right feel and style of each aftermarket strut, that above information is likely more than enough. But if you want to start to understand the science behind how your shock works, read on below.
Looking for the Strut portion of this guide? That’s down below even further. Sorry.
The Physics of Twin-Tube Shocks
First we should revisit the twin-tube shock, which has a cross section like this (image provided by Rancho, specifically the Rancho RS5000X:
So whether you are hitting a bump or a pothole, the piston moves up or down within the main tube there, also known as the Pressure tube. And as the piston pushes down, oil is slowly allowed into the part of the pressure tube above (or in this image to the right) of the piston valve.
The Pressure of this downward motion is converted partially into thermal energy--or heat. This is why after hitting a particularly harsh off-road course or just driving for a long time, your shocks will actually feel hot to the touch.
Some of that Pressure or downward force is also sent through the oil, out of the main Pressure tube and into the “Reserve” tube or Cylinder-the outer layer there. The force then exerts itself upon the gas in that chamber, typically Nitrogen or N2.
Since the area of the outer (Reserve) tube is smaller that the area of the inner (Pressure) tube, what we have occurring here is a true application of the hydraulic principle. Brace yourself cause we are about to get our nerd on.
The Hydraulics Principle
This particular principle has to do with the application of a force, in this sense the weight of your vehicle, on a liquid, in this case the hydraulic oil in your shocks. The principle looks like this:
Force 1 X Area 1 = Force 2 X Area 2
And what that means is any force that acts above the surface area of one end or portion of a body of fluid must be the same as the surface area of the other end. The force cannot disappear because of the laws of the conservation of energy.
Alright, slowing down the nerd train a bit. But what does that mean, really? Well, if say one area is bigger than the other, then the force at the other end will have to adjust accordingly. Let’s make some assumptions here. Let’s claim that the Pressure tube (Area 1) is roughly 3 times bigger than the Reserve cylinder (Area 2) (I’m making these numbers up, by the way, just as an example).
Then let’s say we are putting 150 PSI down on the oil in the Pressure tube. We can use the formula to find out how much PSI will be at Area 2 or what Force 2 equals.
150 PSI X 3x = Force 2 X 1x
Force 2 = 450 PSI
Crazy sauce, right? And that works the other way too, for when your Piston is moving up. Now what happens to that hypothetical 450 PSI when it reaches the gas portion of the Reserve cylinder? I’ll walk you through it.
By the way, as this is all happening, force is being lost to friction, which is part of the reason we are dissipating the force via heat loss. This is why the scientific understand of shocks is that they are dampers. They take Kinetic Energy (movement) and convert it to thermal energy (heat), thus dampening how far and at what velocity your vehicle would move up or down when going over a bump or hole.
A Real World Example: Rancho RS5000X
Now the above example assumes that there is less area in the outer tube or Reserve cylinder. It is certainly possible to design the shock in such a way that both tubes have the same area, at which point the PSI transfer from one tube to the next will be the same, so instead of multiplying the 150 by 3, as we did in this example, it would be by 1, or exactly the same pressure in both tubes.
Let’s actually look at the Rancho RS5000X as an example then to find out if this is true or not. The foundational principles will still remain true, but it is always good to have some idea of how this stuff really works.
So with the RS5000X, we know that the Outer Tube or Reserve Cylinder outer wall diameter is roughly 2.25 inches. I realize that the metal has a certain amount of thickness, but let’s pretend it is negligible and just use that number, partially cause I don’t feel like cutting one open to actually try to measure such a small amount. Sounds like a lot of work.
(Note that if you view the original image file above by opening it in a new tab, for instance, it should display at roughly 4 times the original scale of the shock.)
And we know the the inner tube or Pressure Tube has a diameter is 1 ⅜ inches or 1.375 inches. We can use this simple formula to figure out the Area of each circle then quite easily:
Area of a Circle = pi X Radius2 or 𝝅r2
The Radius is just half the diameter of each circle, so we simply divide that by 2. A visual would likely help at this point:
So we plug the numbers in to find this:
Area of the Pressure Tube is 1.48 square inches.
And Area of the Reserve Cylinder is 3.98 square inches.
Likely we can already see that I was totally wrong in my assumption. The Reserve Cylinder actually has more area, not less than the Pressure Tube. But before we can get the actual numbers, we have to subtract the Pressure Tube Area from the Reserve Cylinder Area because the Tube is taking up 1.48 square inches of that Reserve Cylinder Area. Duh, right?
Now we find that the Pressure Tube is still 1.48 square inches of actual area.
And the Reserve Cylinder has 2.5 square inches of actual area.
Now we can return to our original assumed 150 PSI Hydraulic formula:
Force 1 X Area 1 = Force 2 X Area 2
Force 2 will be the Pressure in the Reserve Cylinder again, just as above, with Force 1 assumed to be the randomly selected 150 PSI.
150 PSI X 1.48 square inches = Force 2 X 2.5 square inches
The numbers will be much more messy now. But we can certainly crunch them.
222 PSI / 2.5 square inches = Force 2
Force 2 at the Reserve Cylinder is actually only: 88.8 PSI.
So we can easily see how advantageous using Hydraulics in this Shock Absorber actually is. It can reduce the force of downward motion on the Shock or amplify the fore of upward motion. This is likely the reason many OEM shocks are Twin-Tube. This makes it less expensive to get standard types of results.
However, the only major issue that may still arise is if the oil gets mixed with the Nitrogen gas causing aeration and hence reduced function. Otherwise, especially on standard road conditions, these shocks should be pretty good at dampening vibrations and forces.
The Ideal Gas Law
Once our hypothetical force meets the gas, we need another formula or physics law. This one is known as the Ideal Gas Law and it looks like this:
Pressure X Volume = n X R X Temperature
While most of those aspects up there are self explanatory (Pressure, Volume, and Temperature, for instance), n and R aren’t really. The “n” in the formula represents the Number of Moles which is just a unit of measurement for how many molecules of gas we have. This number will remain constant because we aren’t adding Nitrogen gas into this closed system. The R represents something known as the ideal gas constant, so it too will not change. Just ignore them for the purpose of this explanation or assume that the n equals one and the R equals 8 (which it roughly does).
So here’s what happens: as our Pressure on this pocket of gas increases, the Volume is gonna have to decrease, but the Temperature is also going to go up. The Volume goes down some because the oil is going to push up into the gas, forcing the Nitrogen to occupy less space. This happens due to the Force of the Pressure. Hopefully this is all making since.
Back to our hypothetical, let’s assume our volume is roughly 2 when the force is applied, but has to then shrink down to 1 from the oil rising into the tube:
450 PSI X 1 = 1n X 8 X Temperature
Now we’ll solve for Temperature to figure out how many degrees Kelvin our shocks are gonna heat up.
450 / 8 = our Temperature increase, which is roughly 56 Kelvin or 80-90 degrees Fahrenheit! In other words, we’re getting hot, hot, hot!
This is also part of the reason why the Nitrogen gas will be put into the twin-tube or mono-tube for that matter under pressure already, so that it can try to hold its own against this downward hydraulic force from the oil, and hence not release as much heat nor cause the piston to depress as rapidly.
So hopefully that helps some and you can understand more fully the science behind how a Twin-tube works.
Our Rancho RS5000X Example Again
If we use our Rancho example once more, we find the Temperature increase at the Nitrogen gas will be equal to:
88.8 PSI / 8 or 11.1 degrees Kelvin, which is only about 18 degrees Fahrenheit.
Now the Twin-Tube will still have to dissipate that heat across the outside surface area of the Reserve Tube, which is likely smaller than any comparable Mono-Tube, so overtime it will still heat up more. Nevertheless, we can still see that Twin-Tubes are going to be able to handle real world examples of typical highway and road driving just fine.
But what about a mono-tube shock? And why did I keep insisting that mono-tubes are in many ways superior to twin tubes. Let’s use another Rancho image, but this time the Rancho RS7000MT Mono-Tube Shock:
Now instead of having two cylinders, we have just one. At one end we have the Nitrogen gas and at the other the hydraulic oil. The Ideal Gas Law portion of this hasn’t really changed, per se. But what about the Hydraulic Principle.
As you will recall from above, the Hydraulic Principle is:
Force 1 X Area 1 = Force 2 X Area 2
Now in the above example, Area 1, the Pressure tube, was assumed to be roughly 3 times as big as Area 2, the Reserve Cylinder. But now we just have one Mono-Tube. The Area of it is exactly the same at both ends. It doesn’t get smaller or larger. So those two are both the same number.
We can then just use the number 1 in place of both. So our formula ends up being:
Force 1 = Force 2
Now why is this better, you might ask? Instead of multiplying or dividing the amount of force or PSI that will hit the Nitrogen gas and need to be dissipated as heat from the Ideal Gas Law and/or friction, now it will remain the exact same amount.
In our Twin-Tube example, we imagined that there was 150 PSI of Force being applied at Force 1, which tripled to 450 PSI at Force 2. But here, if we take the same amount of Force, 150 PSI, we find that Force 2 will also be… 150 PSI. Nice, right?
Just to put this into perspective, let’s plug that into our same Ideal Gas Law formula from above.
150 PSI X 1 = 1n X 8 X Temperature
150 / 8 = our Temperature increase of roughly 18 degrees Kevlin or only 35 degrees Fahrenheit, nearly a third of what we had in that Twin-Tube example.
I hope this helps to explain exactly why Mono-Tubes provide the superior performance. Of course there is even more science behind all of this, and all my examples are hypothetical and ideal. Nevertheless, those numbers do NOT lie. Mono-Tubes FTW!
And don’t even get me started on Tri-Tubes.
Summing Up the Findings
Bigger is Better…?
I hate summarizing anything down to such an aphorism as that, but if it ain’t broke…
Basically, regardless of whether a shock is twin-tube or mono, if it has a bigger Pressure tube, then it can displace more vibrations and dampers better. Hence, a mono-tube that is of the same or similar size diameter (or circumference, if you’re better at gauging that sort of thing) will be a better shock than a twin-tube that is roughly the same size or even a little bigger… Well, possibly quite a bit bigger, see that Ideal Gas Law example above.
This all adds up to one thing: if you want to simply talk about best at stopping vibrations and converting kinetic energy into heat over an extended period of time, the Mono-Tube is your clear winner. Now it still needs to be gas pressurized and well manufactured and all that. I’m not saying the cheapest knock-off Mono-Tube on the market is going to beat out the most expensive, well made Twin-Tube. But if that cheap knock-off holds pressure inside its tube…
I think you get the point here. This doesn’t change the fact that since most stock vehicle shocks are still Twin-Tube, if you want that kind of handling and feel you might want to stick with a Twin. Likewise if you are considering a certain level of adjustment and don’t want to add on a Remote Reservoir, there are some great Tri- and Twin-Tube options out there.
But if you want the best of the best of the best, find a Zinc Coated (most high quality aftermarket shocks are), Gas Pressurized (almost all of the shocks period these days are), Mono-Tube (cause, duh! See above. The Science! The Science!), Adjustable (for added customization and minor tweaking), with a Remote Reservoir (because it will only make that shock do its job more efficiently over a longer period of time). There. I said it.
So for those of you into the numbers, let’s have a look see at some. First, let’s note that some of the manufacturers list units in mm and others in inches. Don’t get confused. You might be tempted to see a larger number and think bigger, but if one measurement is in inches and the other millimeters… yeah. Careful now.
Secondly, while I would like to just be able to look at overall diameter of the shock, I can really only do this with Mono-Tubes. Once we start adding in Twin-Tubes or Tri-Tubes, then things get funky because the bigger size outer body casing doesn’t translate directly to a bigger size piston or Pressure Tube. In other words, when we get to Twin-Tubes / Tri-Tubes, we should look at Piston Diameter to compare instead.
Since that measurement works best for all involved, we’ll have to tread carefully. Some manufacturers might not list their Piston Diameter, so for those we’ll estimate, as long as they are Mono-Tubes, that is. But enough talk. Here’s the chart:
The Best Shocks Currently in the Aftermarket According to the Parts Professor:
Zinc Coated, Gas Pressurized, Adjustable, Mono-Tube with a Remote Reservoir
And I don’t care if it is only adjustable on the reservoir or on the main shock body. That is totally irrelevant to me, though you should consider it if that’s going to be a big deal for you.
Hence, if I had to recommend a pair of shocks for a true aftermarket enthusiast today and not just for a daily driver vehicle, but for a truck or Jeep that does hit some extreme off-road terrain from time to time (cause otherwise these will definitely be overkill), I’d go with one of these for the following categories:
Bilstein 5100 Series
Bilstein’s dedication to shocks over the years, from the innovation of the mono-tube to the game changer of introducing pressurized Nitrogen gas, shows through in all their products, including the icon 5100 series. When it comes to pure off-road performance, Bilstein is just hard to beat. If you are looking for something more street level though, Bilstein has you covered on that as well, but we focused this best of the best section mostly for the Off-Road Enthusiast.
Runner-Up: Fox Adventure 2.0 IFP
Fox’s Adventure 2.0 IFP series is simply a great shock, even when compared to Bilstein’s 5100. Their Internal Floating Piston design is second to none. This is also a great mono-tube shock--truly top of the line.
Best Remote Reservoirs to Add-on:
Fox’s Low Speed Compression (LSC) Adjuster on a 2.0 Reservoir
Now say that about five times fast. Good luck.
Fox’s 2.0 Reservoir makes a fine addition to any of their 2.0 Shocks, whether Adventure or Performance series. And when you tack on a couple Low Speed Compression Adjusters, you’ll get 10 levels of fine-tuning options for your ride. If you are looking for a Reservoir with Adjustment options, this is probably the best one currently on the market. But if you just want a Reservoir, the Bilstein Reservoir, our Runner Up in this category, will do just as well and might come in a few dollars less as well. But for that fine tuning goodness that enthusiasts often want coupled with the Remote Reservoirs added ability to keep your shocks cool and functioning at maximum performance levels longer, Fox’s 2.0 Reservoir with Low Speed Compression is a really excellent aftermarket solution.
Runner Up: Bilstein Remote & Swivel Reservoir
Known for their superior technology and innovation, Bilstein is still rocking it. Bilstein Remotes house the Nitrogen gas chamber, allowing for added space within the shock to be devoted to oil. This significantly increases performance (see Science above. More Volume is Much Better!). Their Reservoirs allow shocks for sports cars to be designed smaller while still maintaining optimal performance. But who cares about muscle cars, right? What about Trucks and Jeeps!? The addition of a Remote or Swivel (Piggyback) Reservoir from Bilstein to each shock allows for increased optimal control at the wheel when heading through difficult terrain. Furthermore, as with most Reservoirs, the additional oil capacity increases the shocks ability to dissipate heat, giving your shocks increased efficiency and durability over time.
Best Mono-Tube with Reservoir included:
Bilstein B8 8100 Series (specifically the 8112)
My editor is likely to call foul play with this one. Not only did Bilstein scoop up the title of Best and Runner Up for Best Mono-Tube with Reservoir included, but I also snuck in a CoilOver. Whoopsie. The Bilstein B8 8112 with ZoneControl® CR, is the creme-de-la-creme of Off-Road shocks (with the price tag to boot). When they claim they’ve perfected damping, they aren’t exaggerating. These shocks are simply amazing. But should they really be in this category? I mean, they are technically coilovers, right? Sure… I guess. So if you forced me to throw out the 8100’s on a technicality, the moniker of Best would have to fall to... Runner Up: Bilstein 5160 Series: Designed for aggressive driving and severe off-road use, the Bilstein B8 5160 series is almost as badass as its older cousin the 8112, minus the coilover goodness, of course. If what you crave is a great shock with a Reservoir included, this is the package for you. The 5100’s are simply excellent shocks--see above. And that Remote Reservoir from Bilstein placed too, didn’t it? Yeah, it makes sense why Bilstein swept this prize.
Best Adjustable (Twin- & Tri-Tubes included):
Rancho RS9000XL Series (Tri-Tube)
If what you want is a truly adjustable shock, without any Reservoir, the clear winner is Rancho. Their RS9000XL series with 9 separate levels of adjustment gets the job done without any added Reservoirs at all. Cory, Big Country, himself, has actually tested these out, and he found that you really could tell the level of adjustment from 1 to 5, all the way up to 9. These shocks and their adjustment levels can be fine tuned once you have them installed, so that you can get the exactly level of ride that you like. While you might not change them much once you find your sweet spot, if you’re ever going to make a long highway road trip, we recommend cranking it down to 1. And if you’re about to hit the Off-Road for some sweet mudding, try out 9. You’ll thank us for it.
Runner Up: Fox Adventure 2.0 Series (Mono) with Reservoir and LSC Adjustor?
We’ve already ranted and raved about this shock and reservoir above, but we thought we’d mention it just the same. If you don’t like the idea of installing a Tri-Tube (or Twin for that matter), we highly recommend you try out Fox’s Adventure 2.0 series with the Reservoir and the Low Speed Compression Adjuster added on. This will give you up to 10 levels of adjustment, and while the add ons alone will end up costing you nearly as much as a single Rancho RS9000XL shock, we don’t think you’ll be disappointed with the performance from this great Mono-Tube Shock.
Ready to Upgrade Your Shocks?
Now I think you’re finally ready to actually order some shocks. I know there were a lot of numbers thrown out there and a lot of science type stuff, but I hope this helps you decide what kind of shocks you really need to have installed on your ride.
If you disagree with any of our picks for best and runner up, hit us up on the socials and let us know just how wrong I am.
And if you’re ready to order your new shocks, we hope you’ll pick up a pair from us, here at Midwest Aftermarket. Our selection is always growing. If you come across something you want and can’t find it on the website, give us a call. We can probably special order those shocks for you. And if you have any questions, you know how to reach us (see below in the footer of the page if you don’t).
Coming up next… Struts.