The BEST RF Springs, the EASY way to lower your MX5 RF correctly! These springs result in about 1 inch of lowering, rates are about 20% stiffer than stock. These are made exclusively for Good-Win Racing for the RF version of the ND MX5 to work with stock shocks and have heights and stance work out correct for the RF version (most OTHER springs not calibrated for higher rear weight of RF end up with rear settling too low eventually and ugly reverse rake jokingly known in the forums as the 'speedboat' look). Rates are specific to the RF version, adding a little more rear spring rate to balance the car correctly with the extra rear weight of the RF version.
Stock heights on our ND were 14.25 to 14.75. Lowered heights with these springs approximately 13.5 inches front, and generally a bit over 13.5+ inches rear (measured car empty centre of wheel up to fender lip, car levels once people are added since driver and passenger are almost sitting on rear suspension).
Note if you add our KONI SPORT shocks they are much lower pressure because of twin tube design as compared with factory monotube and result with KONI shocks will be ANOTHER half inch lower than what we list here. Your results will vary depending on which shock you use and the age of the shocks, as shock pressure declines over time the car will settle lower.
The engineering staff at Progress has decades of experience in the design and tuning of performance suspension systems, including CART/Indy Cars, IMSA, SCCA, NASA, and SCORE competitors. These MX5 springs reflect their ability to develop a successful blend of appearance, handling capability, and ride quality. Our team works with Progress on each MX5 application spring, and with nearly a decade of working with Progress we know the result will show the quality and consistent performance that we feel raises the cornering joy level of the ND platform to a new level.
STOCK spring rates are 156 front for all models, and 80 to 100 rear.