Shocking Developments – How To Upgrade Shocks
Trucks are designed to get used. Whether you haul a trailer or 2 tons of bricks, how the truck handles its payload depends in large part by the shocks. How the factory outfitted your truck varies greatly, some trucks are sold as work trucks with heavy-duty shocks and springs, but most trucks on the road today have light-duty shocks, enough to keep the ride smooth with a modest load in the bed. Drop in a near-capacity weight, and then things are not so smooth on the way home or to the worksite. As your trucks ages, the shocks will also wear out, leading to a bouncy ride that seems more like a bucking bronco. You are not limited to whatever your truck came with from the factory. However, there are several ways to upgrade your shock absorbers to give you better load handling and un-loaded ride comfort. On most trucks, you can do it all yourself, in your driveway, in less than a couple of hours. So follow along as we show you how to upgrade shocks using our test vehicle.
When it comes to picking out your shocks, there are a lot of options. The factory shocks are capable of handling most applications, but there are always better options. A few minutes at your local NAPA store will have you wondering what you need. Here is a quick guide to choosing a shock.
Most factory shocks are of the twin tube variety. This design uses a large inner tube for the fluid and second thinner tube (outer tube) that holds fluid and a gas charge. This provides the best ride and comfort for street use.
These shocks use one tube and two pistons, where the fluid and gas are separated by the pistons, not the tube. Off-roaders prefer mono-tube shocks, as they can be mounted upside down and run cooler than a twin-tube design.
If you are going to be doing some serious off-roading, reservoir shocks may be the best option. These units have a separate reservoir for the damping gasses and yield extreme shock absorption capabilities.
Adjustable vs. Non-Adjustable
Most shocks that you will find in the parts store are not adjustable, but there are a few that are. An adjustable shock gives you the ability alter the valving of the shock itself, controlling compression and rebound. Compression is the shock’s ability to control how fast the shock collapses; rebound is how the shock controls expansion.
- Adjustable shocks come in two flavors – single or double. A single adjustable shock uses one knob to adjust compression and rebound in the same adjustment. These are pre-determined settings, in as few as three and as many as 12 adjustments.
- Double adjustable shocks are for the more adventurous tuner, with separate controls for both rebound and compression. Some shocks have 24 settings for each knob, with a total of 576 total individual combinations, allowing you to tune the shock to match the vehicle and the driving conditions. These shocks are typically used for off-road trucks and vehicles that are used in competitive racing.
For the average street truck, a single-adjustable shock is more than enough to handle the job.
We recently had a 2003 Chevy Silverado 4×4 in the shop and while the truck has a decent ride, cornering gets a bit sketchy with the stock shocks that have 170,000 miles on them. We ordered a set of Rancho 9000 XL series shocks from our local NAPA store and installed them on the truck. These shocks feature 9 settings at the twist of a knob to tune the shock from stock ride, all the way up to a firm ride, for performance and towing. Rancho says that this provides a 400% change variable in ride from softest to hardest. That is a significant difference that you can feel in the truck.
The 9000 XL series is a large-bodied shock that uses a unique triple-tube design with a mono-flow piston for top-end performance; it even comes with a boot for the exposed end to protect the seal for longer life.
The bushings are polyurethane that will last longer than the rest of the shock. When it comes to street and off-road performance, Rancho shocks have the reputation for being the best.
The process for swapping shocks is simple for most trucks. In fact, they can usually be swapped without even taking the wheels off. If the truck is older or has a lot of miles on it, taking it to a car wash and blowing out the dirt and grime from underneath is a good idea. Spray the nuts and bolts on the shocks with some penetrating oil a couple of hours before you do the actual swap, that can make everything come apart faster.
You don’t have to replace all 4 shocks at the same time, but that is generally yields best results. The rear shocks are the easiest to remove and install. We used an impact gun from Ingersoll Rand, but you can get the job done with hand tools. Start by removing the lower bolt, and then the upper. Wear safety glasses to protect your eyes from dirt.
Most shocks come with a retainer strap. Remove the strap and the shock will expand. Don’t worry; you can compress the shaft by hand. Position the shock onto the upper mount, and then pull or push the shock body so that it lines up with the lower mount.
Once they are both in position, bolt them down. You can look up the specific torque specs for your vehicle, and then tighten the bolts to those specs.
Moving on to the front, there are several ways that the factories mount the shocks. The shocks are generally mounted to the lower A-arm or control arm and to the frame at the top. Some trucks run the shocks through the center of the coil spring.
The upper mount on most front shocks is typically a threaded shaft that mount through a hole in the frame. Sometimes there is an eyelet for the upper mount.
Remove the upper bolt first. This usually requires a second wrench on the top of the shaft to keep it from spinning. Next, remove the lower shock bolts. On this Chevy truck, there is no coil spring, so the shock is easy to see.
The lower mount on non HD 1500 trucks uses a U-style lower mount. The new Rancho 9000 XL shock gets assembled with the new boot and positioned.
Install the shock into the upper mount, centering the bushings, and then the lower mount.
You can set your adjustment knob to wherever you want. We started in the middle at 5, and the handling and ride of the truck improved. Settings 7-9 are good for performance driving and tower, while 1-3 are super soft for cruising.
This means the truck is now ready for any type of driving and we can change it when we need to in just a couple of minutes. Make sure that you set both sides to match left and right, but you can the front and rears differently as needed.
After the shocks were installed, we needed to put them to the test. With the stock shocks, the Silverado had a bad habit of porpoising when the race trailer it hauls is empty. Porpoising is when the back-end of the truck moves up and down while towing, much like the tail of a dolphin. Not only is it annoying, it also unsettles the rear suspension, making it harder to handle. The Rancho 9000 XL shocks were set to 9 for towing, and amazingly, the porpoise effect was virtually eliminated, making the ride home from delivering a car much more relaxing.
To learn more about NAPA AutoCare, visit www.NAPAAutoCare.com.