Linear vs. Progressive: Which Lowering Spring is Right for Your S550 Build?
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You’re finally ready to lower your 2015–2023 Mustang.
You want to get rid of that ugly factory wheel gap and stop the nose of the car from diving into the pavement every time you hit the brakes.
You start browsing our premium suspension catalog, and you immediately run into two main terms: Linear and Progressive.
Eibach utilizes Progressive rates for their legendary street kits. Ford Performance often leans toward Linear or Dual-Rate designs for their track packages.
Who is right? Ideally, all of them—it just depends entirely on how you use your Mustang.
- Progressive Springs feature coils that are wound tighter at one end. They remain soft and compliant over small highway bumps (like a comfortable street car) but rapidly stiffen up when you throw the vehicle's weight into a hard corner.
- Linear Springs feature the exact same spacing between every coil. They are stiff all the time. This makes weight transfer incredibly predictable on a road course, but noticeably bumpier on your daily commute.
In this guide, we break down the physics of spring rates, help you decide between the comfort of an Eibach Pro-Kit or the track precision of Ford Performance, and warn MagneRide owners about the "Suspension Fault" trap.
Compare Premium Spring Options
Subtle Drop or Aggressive Stance?
|
Spring Kit |
Drop (Front/Rear) |
Spring Type |
Best For |
|
Eibach Pro-Kit |
1.1" / 1.0" |
Progressive. |
Daily Driver. The absolute perfect balance of removing the wheel gap while retaining ride comfort. |
|
Eibach Sportline |
1.5" / 1.3" |
Progressive. |
Stance. An aggressive, deep drop. Requires aftermarket Camber Plates for proper alignment. |
|
Ford Performance |
0.8" / 0.8" |
Linear/Dual. |
OEM+ Builds. A conservative drop that massively improves track handling and keeps factory warranties happy. |
|
Roush Performance |
1.1" / 1.0" |
Progressive. |
Street Tuned. Designed specifically to maximize the grip of standard street tires. |
Frequently Asked Questions (Lowering Springs)
What happens if I put standard lowering springs on a MagneRide car?
The ride will be terrible and you will get error codes.
The MagneRide computer adjusts the magnetic fluid stiffness of the shock 1,000 times per second based on the exact position of the wheel. Standard springs permanently change that position outside of the computer's expected range, causing it to constantly over-correct. This results in a harsh "pogo stick" bouncing effect and will immediately trigger a "Service Suspension" light on your dash. Always buy MagneRide-specific springs from Eibach or Ford Performance.
Do I absolutely need an alignment after installing springs?
Yes, do not skip this step.
Lowering the car permanently changes the geometry of the suspension control arms. It usually adds excessive "Negative Camber" (the tops of the tires leaning inward) and completely throws off the "Toe" (the direction the tires point). If you don't get a professional alignment within 100 miles, you will destroy the inner tread of your expensive front tires.
Will lowering springs blow my factory shocks?
It depends entirely on how low you go.
- Moderate Drop (~1.0 inch): Your factory struts will handle premium kits like the Eibach Pro-Kit or Ford Performance springs perfectly fine for years.
- Aggressive Drop (1.5+ inches): Deep drops like the Eibach Sportline put significantly more stress on the factory dampers, causing them to wear out (and bounce) much faster than stock. If you go this low, we highly recommend upgrading your shocks at the same time.
Fix the stance.
Get the aggressive look you want and the handling your chassis needs. Shop our verified collection of premium 2015–2023 Ford Mustang Lowering Springs.