Suspension formula (SR)

  • Thread starter Thread starter Area66racing
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Area66racing

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United States
I keep it short....

1.convert front ride ht to mm since thats what the sr uses.
2.get kg of front weight dist.
3. F wt/rh (mm)/9.8= nSRf
R wt/rh (mm)/9.8= nSRr

Ex. R18
Wt 900kg
Wt dis 49/51 or 441/449
Rh 80in. Or 3.144 mm

Front: 441/3.144/9.8=14.31
Rear: 449/2.986/9.8= 15.34 ( changed rh to 76in.)

9.8 is gravity or kgf (kilogram force)
More to come
 
Two problems with this approach. First, there's fairly good evidence that GT factors in suspension motion ratios in some form or another. For example, there's some cars with close to 50/50 weight distribution but radically different front and rear springs. As soon as you even out the springs the car's handling goes to crap. Without knowing the motion ratio we can't determine wheel rate, which is what actually matters. Second, ride height is not particularly useful for calculating spring rates. What we need to know is suspension travel, or how car the suspension can compress before hitting what I would call a virtual bump stop. Again, another total unknown.
 
im using ride ht for the suspension travel to figure the rates. I've been dooing some expermiting with it and will revise it soon the base of my formula is converting rh to mm because spring rates are kgf/mm. My thoughts are adjusting rh values in the formula for bumpier/ smoother tracks but not actually adjusting rh in the setup so a car could use a value of 50 in the formula to represent sus travel but keep its actual rh at 80. A work in progress.
 
Ride height is already in millimeters, not inches. It's the distance from the ground to the underside of the car, not the top of the roof. I still think there's not enough information to do this effectively, but best of luck anyway.
 

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