View Single Post
Old 06-24-2019, 06:35 PM   #207
949 Racing
FT86Club Official Vendor
 
949 Racing's Avatar
 
Join Date: Jan 2012
Drives: Miata, GT350, FR-S
Location: California, USA
Posts: 422
Thanks: 28
Thanked 919 Times in 300 Posts
Mentioned: 10 Post(s)
Tagged: 1 Thread(s)
Quote:
Originally Posted by Clutch Dog View Post
Im facing this issue. im on swift spec r springs on koni's and it sits too low for me. I just wanted stiffer rates

Im hoping this street package will be perfect for my usage
Our Street spring pack is slightly softer than OEM rates, not stiffer. Its important to discern whether you actually need higher rates or merely want better response and control without sacrificing ride quality. IOW, don't chase higher rates unless you actually need them.


Generally speaking, higher spring rates are simply tied to load that the vehicle will see. Whether that's towing hauling in a truck or cornering harder in a passenger car. A low grip OEM tire can only generate so much lateral grip, which limits how much force is trying to make the body roll. This is the RM (Roll Moment). More grip = higher RM. Higher RM means a suspension is more likely to get too far into the bump stops while cornering hard. Touching the bump stops intermittently at peak lateral G on a bumpy track is OK, but just camping on them even in smooth turns causes major handling problems.
The stock shocks do this, riding on the bump stops in high G turns when sticky tires are added.

So the first question we ask customers when they ask for advice on springs rates for their Xidas, is what tire they are using. Generalizing here but we would suggest running no more than a 225/45/17 280tw tire with our Street spring pack. If you run say, 255/40/17 200tw tires on the Street springs, you will overwhelm the springs even with the dampers set full firm.

The dampers (shocks) themselves play a role in handling roll and pitch moments. Valved and dimensioned correctly for the application and you can get away with lower spring rates. 86 Xidas have increased bump travel over OEM so in effect, more useful travel before the bump stops are engaged. Combine that additional bump travel with better low speed (piston speed, not vehicle speed) damping and you gain suppleness over rough pavement. That's where the grip and composure come from.
__________________

Last edited by 949 Racing; 06-24-2019 at 06:49 PM.
949 Racing is offline   Reply With Quote