Quote:
Originally Posted by Shankenstein
From your testing, what would you expect to be the bias on our cars for road race tuning?
Looking at the RCE Tarmac 2 Clubsport (as an example), they use 400/400 spring rates, which puts a ~23% biased towards the front (using the motion ratios from my data thread). Stock is ~27% biased toward the rear.
I've always heard that autocross and racing with RWD tends to work well using a stiffer front than rear. You get a planted feel during slaloms, but better power delivery. There is a penalty with regard to weight transfer, but it's faster because each end of the car can do its job more effectively.
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I don't have a twin yet. What I would
expect are wheel rates that are fairly balanced with respect to the weight distribution. I am not contradicting myself as it's a function of many things including the amount of power, tires, ARBs, downforce (not on this car) etc and ultimately the course layout. For a twin, if the spring/shock motion ratio in front is closer to unity than the rear, which I would assume is the case, I'd expect the
spring rate bias to be somewhat rearward. What are the stock spring rates?
Slow course layouts such as autocross and slaloms have different requirements compared to road racing. Power-down, drive-off, or whatever you want to call it is of the utmost importance I would think especially for cars that are massively traction limited (big power) rather than momentum cars when navigating around cones. Then you would want, all else equal, to move the
spring rate bias more forward to help with longitudinal acceleration performance.