Nitro\Electric Touring Car Spring Rates

[hypertech]

I was wondering if anyone can explain why it is the norm to spring a 4wd touring sedan so stiffly ? When I look at the setup sheets out around the web for all electric and nitro touring cars I see spring rates that to me seem pretty high given the weight of the cars. I can fathom the fact that increasing spring rate will help keep the car flatter in the turns and make it more responsive to control inputs but geesh a 15-30 lbs per inch spring at all four corners seems alot for a 4lb car. Your talking at least a couple of G's to even begin compressing a 20lb spring with a 4lb car....

Why not use softer springs to get a car with some feel to it in conjunction with anti roll bars to control body roll ?

By saying a car with feel I nean you can sorta feel when it's reached it's G load limit instead of a like with a stiff car you have no warning of when it's gonna break loose or flip on it's roof....

[RC10T3]

becuase there are a ton of g-forces excerted on these cars. People racing on carpet tracks have snapped graphite plates becuase of the lateral forces put on them, and I myself have cracked a-arms and such just from the carpet catching the arms so hard. Plus, its all about consistency. A loosely spung car will shift its weight around too much, causing the diffs to unload as the tire comes off its contact patch.

[hypertech]

Originally posted by RC10T3
A loosely spung car will shift its weight around too much, causing the diffs to unload as the tire comes off its contact patch.


But isn't that what anti roll bars are for......to help control some of the side to side weight transfer when turning (ie: keep the car flat). Damping helps control the power on\off & side to side weight transfer reaction time. I just thought springs were supposed to be used to suspend the weight of the car and components, a 20 lb spring seems like over kill given that 20lbs would be required to compress the spring fully which is at least 4 times the weight of most cars. Now I'm not trying to start an argument or anything I'm just trying to figure out how come everyone is doing it and if there is a good theory as to why we spring so heavy in the 4wd touring car classes. Such springs would be a no no in offroad and most of my experience is in offroad so these high rate springs are a new thing for me and seem backward to what I'm used to. Also the percentage of weight to rate is way up there in the 4wd touring class, considerably higher too than the formula that is used for real race cars and much higher too than the percentage used for offroad cars.