Ever since it was announced that the S550 Mustang platform would officially transition the car to IRS across all models, we’ve heard plenty of concerns across the Mustang community about wheel hop. Some believed the nightmares of the issue that plagued 1999-2004 Cobra owners were going to be relived through 2015 Mustang wheelhop. While Ford did their best, NVH standards, and ride quality take precedent, and while not as bad the old Cobras, the S550 is still a hopper when you apply enough power to spin the tires.
Since the S550 went on sale to the public, BMR Suspension has had these cars in house for testing, research, and development. Their latest video highlights how they’ve eliminated wheelhop from the S550 Mustang without making major sacrifices to NVH and ride quality. Best of all the solutions they developed work for everything from a stock car, to someone blasting single digits in the quarter-mile.
As the video explains, a big part of the problem is the bushings that Ford chose for the S550’s rear suspension. These bushings feature voids, which allow them to be compliant. That compliance however, also allows them to flex significantly under load, this in turn causes wheelhop. Whether the car is stock, or making big power, wheelhop breaks parts. The violent and rapid movement of the suspension components can quickly cause damage to the suspension and rear axles.
Left: The stock bushings feature voids, or pockets, which allow for compliance and NVH control, but also allow wheelhop to occur. Right: The BMR spherical bearing installed in the lower control arm allows for no deflection.
Fortunately, BMR has a solution, they’ve spent months researching, developing, and testing their parts for the S550. The solution is a complete package that includes a BMR Spherical Bushing equipped lower control arm, BMR Delrin Cradle bushings,95 durometer polyurethane differential bushings, billet vertical links with a rod end/delrin combination of bushings. The factory toe rods are reused, and in the video the test car is wearing Mickey Thompson ET Street Radial II tires.
The results are impressive. The car no longer wheelhops with these changes, and the pinion rise that is present with the stock bushings is greatly reduced. BMR offers spherical bearings for the differential, but these should probably be considered only for the most hardcore applications, since they’re going to greatly increase NVH inside the car.
This video is packed full of great information on resolving wheelhop in the 2015 Mustang. We look forward to seeing what else BMR comes up with for these cars in the coming months, and look forward to testing some of these parts ourselves.