FAQs & Tech Tips

MM News

NASA Racers! MM will support NASA road racers with $1,000 contingency prizes for the American Iron, American Iron Extreme, and Spec Iron at the 2019 National Champions. You must register to be eligible.

New! Read the article Maximum Motorsports Tames Fox & SN95 Mustang Rear Suspensions on FordMuscle.com.

MRT Exhaust! MM now offers premium MRT cat-back exhaust systems for 1996-2004 Mustangs.

New! for Street & Strip Mustangs! Big-bore rear wheel cylinders for 1979-1993 Mustang with 9" drum brakes. Improves braking when running big rear tires and front skinnies, and/or different OEM front brakes.

New! Swapping a Coyote into a Fox Mustang? MM's Hydroboost Conversion Kits allow easy installation of a 1996-2004 Mustang Hydroboost power brake assist unit into a 1979-1993 Mustang.

New! Swapping an IRS into your Fox Mustang? MM makes it easier with a brake line kit made just for this conversion. Bolts-in, with no cutting or flaring of brake lines. Designed to fit standard IRS brake hoses.

New! MM's billet aluminum Pedal Box Spacer for Fox Mustangs. Replace the breakage-prone OEM plastic spacer when converting to manual brakes or Hydroboost.

Canadians! Please read the latest about ordering from Canada/shipping to Canada.

We've posted the parts list and link to the video of MM's Mustang in /DRIVE Tuner car Shootout

MM Coil-over Spring, 175 lb/in, 11", 2-1/4" diameter
Actual product may differ from photo.


  • Item # 225.175.11
  • Manufacturer: Maximum Motorsports


MM-designed this barrel-shaped spring for rear coil-over conversions in 1979-2004 Mustangs.

Does NOT fit 1980-1988 Thunderbird because the barrel-shape of the spring interferes with the unique Thunderbird rear shock tower.

  • Unique barrel shape increases the radial clearance between the spring and the threads on the rear shock.
  • The additional radial clearance keeps the spring from rubbing on the threads, a common problem with standard coil-over springs.
  • More overall travel is provided by the barrel shape than by a conventional straight spring of the same rate and length. More travel is added insurance against the spring coil-binding, even when a low rate is installed in a heavy car.
  • Barrel-shaped Coil-over Spring
  • 175 lb/in spring rate
  • 11" free length
  • 2-1/4" inside diameter
  • Designed by Maximum Motorsports.
  • Manufactured in the USA.

1 spring