How to Choose Spring Rate for Coilovers

How to choose the coilover spring rate? Every car has a different weight depending on the vehicle’s design, the options added to the car, and the number of passengers the vehicle is designed to carry. Soft springs improve ride quality, while a higher spring rate introduces a harsher ride and compromises ride quality.

Softer spring rates ensure that the tires maintain contact with the road surface and hence provide better control. Adding shocks controls the speed of compression and depression of the springs. Sway bars limit body roll. Calculators are available to help determine the perfect spring rates when using coilovers.

Coilovers are springs enclosing the shocks specifically designed for your car to provide the correct ride preload. Selecting the correct spring rate ensures that the shocks operate in their sweet zone providing the dampening appropriate for the weight of the car and the desired performance of the driver.

What is a good spring rate for coilovers? 

Everything you do to your car in terms of modifications that add or subtract weight, including the number of passengers carried, affects the spring rate and the performance of the coilover springs.

The job of the spring is to sustain the weight of the car. Higher spring rates reduce body roll but deliver a harsher ride. While a softer spring rate will improve ride quality, the tires can follow the road surface better and avoid  losing their grip on the track.

Shocks have a limited range of motion. The spring rate needs to make sure that the shocks operate in this range to avoid bottoming and topping out as the car corners or hits rough patches in the road.

The springs should ensure that the shocks always operat in their sweet spot. In most cases, the travel space for shocks should be no more than three to four inches.

If you travel on predominantly smooth roads, the springs should position the shocks to travel If you travel on predominantly smooth roads, the springs should position the shocks to travel 50% in either direction. To deliver a smoother ride and allow for road hazards, street cars that encounter many different road conditions should be positioned for the shocks to have 60% allowed for compression.

How do I know what size coil spring I need?

Selecting the size of coil spring needed for your vehicle is based on the amount of weight that must be supported by the spring and the ride height you want to achieve. The weigh that must Selecting the size of coil spring needed for your vehicle is based on the amount of weight supported by the spring and the ride height you want to achieve. The weigh that must be used is the sprung weight and not the unsprung weight.

For example, if the corner weight to be supported is 1000 pounds and the spring rates is 200, the spring will compress five inches under the weigh of 1000 pounds.

A compression of 5 inches should place the spring in the sweet spot of the shock and allow the shock to compress 50% in either direction unless you are driving your car on the street, in which case you would aim for a 60-40 split.

If you plan to customize your vehicle, you will need to measure the corner weight of your vehicle and figure out what spring will be needed to support the weight of the car to provide the appropriate amount of travel and ride height.

Adjust the ride height by varying the coilover spring rate installed. For example, using 150-pound spring rates on a 1000-pound vehicle would cause the ride height to change substantially to more than 6 inches.

MaXpeedingRods offers various of coilovers with regular value spring rates to fulfill the needs of most vehicle owners, and based on its 16 years of suspension manufacturing experience, MaXpeedingRods are also incredibly flexible in providing customized service on spring rates.

MaXpeedingRods Coilover Kits

• 24 levels of damping adjustment for good handling
• Able to lower the ride height by 1”-3”
• High tensile strength performance spring
• Make custom spring rates to your exact specifications