Have you even ridden in an older vehicle and when it hit a bump, you felt like the front end was never going to stop bouncing? Or been in a sports car and it felt like someone was shaking you? The spring and shock package of these vehicles plays a huge role in the ride characteristics.

SpringsA spring’s job is to hold the vehicle up. As the vehicle goes over bumps, around corners, over curbs or anything that isn’t flat, the suspension moves up and down. This movement is caused from additional forces acting on the suspension, causing the spring to compress or expand.

Most springs provide a linear force. For every inch the spring is compressed (or degree of twist in torsional springs) it provides a specific amount of force. It doesn’t matter if that spring is compressed from six inches down to five, or from three inches to two; the increased force provided by the spring is constant.

In an ideal world, the spring would oscillate forever. You hit a bump today and by the time you are ready to retire, your vehicle will still be bouncing. Now we don’t live in an ideal world, and there is damping that naturally happens. This damping causes the oscillation to decrease over time. Even so, a vehicle would still bounce for quite some time before settling back down if a shock wasn’t installed.



The shock really is a key part of the ride quality and that’s been a major focus for Skyjacker — Lonnie McCurry Jr

“The shock really is a key part of the ride quality, and that’s been a major focus for Skyjacker,” said Lonnie McCurry Jr of Skyjacker Suspensions. A shock’s job is damping or resisting movement. This damping dissipates energy created by the suspension moving. The amount of damping directly relates to the amount of time it takes to settle the vehicle down.

For most vehicles, there is a single shock at each corner. Sure, some guys will run multiple shocks up front, but most of the time, a single shock could do the same job (ignoring racing or specialized applications) be it a different or unique shock.

When it comes to shocks, it is hard to tell one apart from another externally. Really, there is a round tube with a rod that goes up and down inside of it. Whether it is a five dollar or hundred dollar shock, most of them look pretty much the same. (Outside of the high performance shocks with remote reservoirs, they at least visually look different.)

We got with Lonnie McCurry Jr. at Skyjacker Suspension and discussed their shocks and how to tell them apart. Skyjacker shocks are extremely popular, easy to find, and fairly simple to understand.

“The Hydros we generally use more on the lighter-weight, smaller vehicles [roughly less than 6,000 lbs] you can use them with bigger heavier trucks they just don’t perform quite as well. For the bigger heavier trucks we usually step up at least to the Nitro shock,” explained McCurry.

Hydro Shock

Nitro Shock

That’s not to say that a Nitro shock won’t work on a lighter vehicle or a Hydro on a heavier vehicle, it is just a matter of how they are designed. You can certainly put a Nitro on a Jeep and benefit from the improved gas dynamics of the shock.

The Hydro and Nitro shocks are split by weight because of the valving inside of the shocks. The valving is what determines the amount of damping or resistance to movement. All of the Hydro shocks use the same valving. The difference between part numbers are for fitment. The same is true with the Nitro line. They use a different valving than the Hydro, but all of the Nitro shocks have the same valving. “One valve code across-the-board is an average, the valving is not vehicle specific whether it’s on a Super Duty or Jeep,” mentioned McCurry.

Green Jeep Mono

The Hydro shocks are a hydraulic shock meaning there is hydraulic fluid inside of the shock. As the piston rod moves, the washer like valves that are connected to the piston move too. This movement displaces the hydraulic fluid. As the fluid moves through and around the valves, the design of the valves creates turbulence which dissipates energy.

The Nitro shocks have nitrogen gas pressure inside. As the piston rod moves up and down, the gas is forced to move around and through the valves. The easiest way to tell if you have a gas-filled shock or a hydraulic-filled shock is to see what happens when it is disconnected. The hydraulic shock will not extend itself, whereas the gas-filled shock will extend.

Monotube Shock

The best shock that Skyjacker makes is the Mono-Tube shock. These are nitrogen filled shocks like the Nitro shocks, but that is about where the similarity ends. “We look at what application the shock part numbers can be used on and then we have different valve codes depending on how the shock might be used. For example if you take a 2500 HD pickup truck with an IFS, it needs a much heavier and much different valving then a Jeep Wrangler JK.

“Even on that 2500 HD there is a different valve code for the IFS front vs the solid axle leaf spring rear. The IFS moves more frequently and at a quicker rate than the leaf spring in the back. So we use a different valve code between the front and rear of that truck to keep the ride quality balanced and controlled,” explained McCurry.

Chevy ActionHaving each shock tuned for each application requires much more engineering time and more part numbers. As a result, the cost of the shocks increases. Another aspect of the difference in cost is the construction itself. “A lot of times people are confused a little bit by the Mono-Tube because they have a skinnier outer body and people think it’s not as heavy duty as the Hydro or the Nitro.

“The technology inside the shock makes it work better. The Mono-Tube offers a whole different level of seals, and it’s a stronger outer body. The Hydro and Nitro are thinner gauge, but it’s double walled. People can dent the outer wall and it’s not really going to affect the shock. You would have a hard time dinging a Mono-Tube just because it’s a stronger heavier outer wall.” commented McCurry.


The Nitro and Hydro series shocks must be mounted with bodies down and pistons up.

“Another difference between the shocks is that the Mono-Tube is omnidirectional. They can be mounted upside down or right side up and it doesn’t affect how the shock performs. With the Hydro and Nitro it has to be mounted with the body down because the valves are intended to work in that direction. Also, there are times where you get into a clearance issue on certain applications and you’d really want to turn the shock over. With the hydro and Nitro shocks, you are locked in and have to be sure that the shock will clear that particular application. Whereas the Mono-Tube shocks can be mounted either way,” continued McCurry.

All ShocksReally when it comes down to Skyjacker shocks; it is a good, better, and best scenario. Even their entry level shock is much better than a standard off brand shock. “I know for us when it comes down to it from a sales point, the Hydro shock is always good at being a lead in.

“They are a price conscious shock for the budget minded person, but it’s still a good performing shock. It’s not low-end even though for us it’s our most economical. We still wanted a shock that, even at its price point, can perform very well.” finished McCurry.

When you think about how often you change the shocks in your vehicle, it might be worth doing a little more research into shocks to figure out which one will perform best for you, and which will last the longest. Skyjacker offers a limited lifetime warranty on their shocks. That tells us, they are putting their money where their mouth is.