Ford Mustang Suspension Guide - Suspension Dimensions - Tech

Q: How do dampers and coil springs work together?
A: "Springs and dampers work together to keep the tires in compliance with the road. The springs compress and rebound as the vehicle goes over bumps and dips. The damper controls the speed at which the springs compress and rebound to ensure the tires follow each bump or dip. The idea is to keep the vehicle moving at the intended height while the suspension moves to keep the tires on the road."

Q: Are different spring rates required for different suspension setups, and if so, what are the differences and why?
A: "Yes, there are different spring rates required for different suspension setups. If you're working with an available damper, whether an OE damper or aftermarket damper, you want enough rate for responsive handling and reduced roll but not more than the dampers can handle. Different vehicles will have different suspension designs. You may have suspension geometry that is increasing rate, decreasing rate, or linear."

Q: What do you look for in an aftermarket antiroll bar for stock springs and aftermarket springs?
A: "You must select the correct combination of spring rate and bumpstops to work with the available damper and antiroll bars. Of course, you can change your dampers and antiroll bars. You will look for roll bars with increased rate to help reduce body roll and control oversteer or understeer. Using aftermarket rollbars with stock springs will reduce body roll but keep the stock spring rate. The key is to have your entire suspension system performing at its best for either track or street conditions."

Coilovers, The Other Spring

Once thought of as a race car-only item, a coilover suspension is now far more common-place in the Mustang world. The stock '79-'04 Mustang front suspension design has the spring located between the control arm and the chassis, and while the handling of the car can be improved by switching to higher-rate springs, ride qual-ity begins to suffer, especially with rates over 850 lb/in.

A coilover kit allows installation of springs that provide wheel rates (different than spring rate) that are much higher than the wheel rates of an 850 lb/in spring that are left in the stock location. Higher wheel rates dramatically reduce body roll and brake dive, and improve steering response. The stock coil springs are also quite heavy compared to their coilover counterparts, as coilover conversion kits replace the cumbersome stock coils, with much more compact, lightweight springs that fit over the struts and shocks, hence the "coilover" terminology.

According to Maximum Motorsports' Chuck Schwynoch, this optimum spring location reduces suspension bind and unsprung weight, allowing the suspension to be far more compliant. This provides significant gains in grip because the suspension can more easily follow the road surface. Improved suspension compliance also drastically reduces impact harshness, resulting in improved ride quality, compared to any spring placed in the stock location.

"Vehicles being tuned for better handling will benefit from the higher wheel rates and the ride-height adjustment offered by a coilover setup," Schwynoch says. "Infinitely small increments of adjustment make precise corner-weighting a breeze, and Maximum Motorsports' coilover kits are available with a wide variety of linear rate springs for fine-tuning of the car's handling balance and the unique weight distribution of a particular vehicle."

You'll also find a lot of drag racers using coilover setups as well. Using coilovers provides a significant weight reduction in the place where Mustang racers need to remove it the most-over the front end. But you do tend to give up travel, which is a must for many drag cars. Schwynoch says coilovers increase weight transfer by providing bind-free suspension movement, and the ability of coilovers to allow precise ride height adjustments also aids in tuning the vehicle for optimum performance.