Progress RF Springs

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 Miata 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. Detailed specs below:

Ride Height
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 center of wheel up to fender lip, car levels once people are added since driver and passenger are almost sitting on rear suspension).

Spring Rate
STOCK spring rates are 156 front for all models, and 80 to 100 rear.
Progress RF Spring rates 185 Front, 135 rear.
These MX5 RF springs feature increased spring rates for upgraded handling capabilities. These springs are designed to work with OEM shocks and bumpstops but will benefit further from using high performance shocks such as Koni Sport shocks. Progress specifies only certified high-tensile SAE spring wire materials. Their MX5 springs are cold-wound on modern CNC coiling machines, then stress relieved, pre-set, and shot-peened for maximum durability.

-All spring kits are powdercoated metallic gray.
-Drop amount varies by 0.25" depending on shocks used.

BRIAN'S APPLICATION NOTES: These are a great choice for those who want to replace the soggy factory springs to take out some of the crazy factory body roll, and improve handling, without dropping the car a lot. Lean on them in the turns and you will find the car is flatter and faster because the tires stay flatter to the ground instead of rolling onto the sidewalls as happens with the soggy factory springs. For those who want MORE DROP than the the springs provide, combine these springs with our KONI SPORT shocks. For those who want the car even more flat in the turns, combine these with our Sway Bar Upgrades. I recommend our SHORT BUMPSTOP KIT (item 61-3050 on this site) with these springs.

INSTALL NOTES: As with the NC, so it also important with similar ND to not lock down the bolts to the suspension after install while the car is suspended in the air with the suspension fully extended. Bounce it on the ground, then give it a drive around the block with the bolts just snug so you get it to settle before you torque everything ON THE GROUND. Many shops will NOT know to do this...SMART CUSTOMERS PRINT ALL THIS PAGE FOR THE INSTALLER! See details in our forum installation section from NC application, thread is titled: "Spring Installation, Mazda Workshop Manual Notes" and factory TSB notes below. Once you do it right, drive it 500 miles and then do it again (which usually results in another quarter inch or more of lowering)....and then do the alignment. ROCKY'S TIPS: Our head mechanic Rocky has his own method that seems to work even better than the factory TSB. Once he finishes install at each corner he jacks up just that corner with BOTH UPPER AND LOWER LINKs loose, so the full weight of the car is compressing just that corner, then he torques the bolts...and he finds car will still settle with 500 miles but usually only another 1/8th inch.