Heavy Duty Coil Springs

Why Should I Upgrade to Heavy-Duty Coil Springs?

The reasons to upgrade to a heavy-duty coil spring vary from vehicle to vehicle. Heavy-duty coil springs will fight sagging. The reason for the sagging is what is different from vehicle to vehicle.

• Under-Sprung – Many motorhomes and trucks (especially with diesel engines) were under-sprung from the factory, meaning that the spring rate was too low for the weight of the engine and the contents of the vehicle. Trucks with diesel engines and motorhomes tend to sag in the front, and the problem may become more pronounced over time. Moving to a heavy-duty coil spring can correct the sagging and even be used to lift the front over stock height, and act as a leveling kit.
• Snowplows – Adding a snowplow is the most common reason for Heavy Duty coil springs. Snowplows can range from 400 lbs. to well over 1,000 lbs. plus the weight of the mounting system. With all the extra weight, the front of your truck can be pulled down to the bump stops. This will make your truck ride rough and the lower ride height will make it difficult to get in and out of driveways without bashing your plow brackets. If you are looking for additional support for your snow plow, we also recommend Timbren Suspension Kits. Timbren kits are a rubber helper spring kit that have been used on commercial and municipal snow plow trucks for years.
• Accessories – Winches, aftermarket bumpers, brush guards, and tire carriers will all add weight to the front of the truck that was not factored in when the springs were equipped at the factory. Increasing the capacity of the coil springs will help return the ride height to its indented setting and can restore the suspension travel that is lost when the extra weight pulls the front of the truck down.
• Vehicle contents – Motorhomes and work trucks may be carrying more weight than they were originally. Motorhomes may be filled with items used for living on the road and work trucks will be filled with items for working on the road. The extra weight can cause sagging in the front and the rear of the vehicle and moving to a heavy-duty coil spring can permanently restore the ride height.

What options do I have when purchasing Heavy Duty Coil Springs?

Coil Spring type

Many Heavy-Duty coil springs will be available in constant rate or variable rate options. The winding of the coil is tailored towards the recommended use of the coil and the weights that the coils are meant to support.

• Variable rate - A variable-rate coil will have a winding that is inconsistent. A section of the coil will be wound with the coils father apart and the gaps will close as you progress further down the coil. The area with the open winding will allow a smooth ride as it will collapse with less resistance, much of the time the truck will be riding in this lighter coil section. In situations of higher load, the lighter coil section will collapse, and the tighter wound section will begin carrying weight. Progressive rate coils are great for leveling springs, but they are not recommended by heavy haulers or someone who carries extra weight consistently. A higher weight will overwhelm the lighter coil section and cause the ride height to sink many inches before the entire coil is supporting the load.
• Constant rate – Constant rate coil springs will have a consistent wind through the entire coil spring. Weight will always be distributed evenly through the coil and the coil will compress less under load than a variable rate coil. Constant rate coils are used for heavy haulers that haul extra weight consistently or very frequently as they will handle the extra load while losing less height than a variable rate spring. If the truck is unloaded the ride may become stiff since the constant rate coil lacks the lighter wound section.

Stock and lifted height options

When replacing stock coils with HD options it can also be a time to consider installing a lifted coil. If you have been considering a leveling kit using a lifted height HD coil can give you the best of both worlds.

• Stock height – Many heavy-duty coils will be designed to keep your truck at the stock ride height. This allows you to increase the carrying capacity without replacing other components or giving it a lifted appearance. Stock height coils are very popular on motorhomes that will benefit from stronger coils in the front, but a lift would cause them to ride nose high.
• Lifted height – If work on the front end is already being performed by changing the coils you can also have the added benefit of a leveling kit by using a lifted height coil. With lifted heights up to 2.5” on some applications you can have the benefit of stronger coil springs with the visual upgrade of a leveling kit by replacing just the coils. Keep in mind that on height increases around the 2-2.5” mark it will most likely be necessary to install lifted shocks along with the lifted coils.

Weight Capacities

When choosing a replacement coil spring set it may be beneficial to weight the coil-sprung axle of the vehicle at a public scale or a recycling center. This will give you the real working weight that your vehicle is carrying. It can be tempting to buy the strongest coils that are offered for your application but by ignoring the weights that the new coils are designed for you may overshoot your needs and end up with an unbearably stiff ride quality. On the opposite end of the spectrum if you undershoot your needs the new coils that you install may not be enough to fully solve your sagging problem. Educating yourself about the weights that your vehicle is carrying will make the purchasing and installation go smoothly and the results will be satisfying.

Will I need to purchase anything else when installing Heavy Duty Coil Springs?

• New Shocks - Extended shocks for lifted trucks should be installed if a lifted coil is installed that puts the factory shock close to its maximum extended length. Normally any lift 2” or higher will require a lifted shock. When using a stock height coil new shocks will not be necessary but if they are higher mileage items it may be a good time to replace them while the front end is being worked on.
• Wheel Alignment - When installing HD coil springs or doing any modifications to the front suspension of your vehicle you should always have an alignment performed after the work is complete. This will ensure that the vehicle performs as intended and it avoids excessive tire wear.