spring rate of 2017 BRZ / 86
 

does anyone know? Google search didnt really bring up anything.. was wondering if any independent shop has already found out...

thanks.

Bump, wondering the same thing.

I fit 2017 MY rear springs. Journalists claim these are 10-15% softer than 2013-2016 springs. From the ride improvement I'd say that's about right, seat of the pants. In fact, ride improvement alone is reason enough to fit these. They are a more grown up spring rate. No doubt Subaru thought so too as the BRZ is now into its fifth model year without significant changes. Rumours persist that the replacement will be more Toyota than Subaru. These changes may attract a wider audience than the harder core initial design.

2017 also fits a 15 mm rear roll bar versus 14mm on earlier cars. The front spring rate was increased but since I kept my 2013 front springs I can't estimate that difference.

I did fit a Whiteline 20 mm front bar and would guess Subaru used the higher spring rate instead of a thicker front bar.

Since I have a Supercharger I decided to leave the front springs alone but soften the rear rate. Lower rear roll resistance improves traction especially exiting corners. The stiffer front bar gives a similar effect to higher rate front springs.

Since I fit the Bilsteins intended for the higher rate rear springs the effective rear damping rate is a bit higher than Bilstein intended which is something MCA recommends if you fit their traction brackets, which I did.

Still winter up here so the ultimate effects on chassis balance have yet to be explored but in the wet or on snow the softer rear springs really help traction, especially in corners.

If the 2017 rear springs prove to be too soft on dry summer roads I intend to fit a Whiteline 16 mm three position adjustable rear roll bar with stiffening brackets. I would then use the softest setting for winter and a harder setting for summer. The three holes each side provide for five different effective roll bar rates.