Spring SPECS?

[philndz]

Does anybody have a compilation of lowering spring specs....It would be great to compare the spring rates and drop measurements between the different brands. Hotchkis rates?Progress rates?others?

[philndz]

Found Hotchkis : 180lbs - Front & 380lbs - Rear

[MadBill]

Err... Could that be backwards, phil? Maybe 380 F, 180 R?

[philndz]

I sure hope not....rear should always be tighter....well, if you want better handling that is.

[shibaman]

That is correct. Hotchkis is the only one with that high of rate on the rear. Great for handling but some times a little stiff on the bad roads.

[MadBill]

Quote, originally posted by philndz »I sure hope not....rear should always be tighter....well, if you want better handling that is.Hmmm.. Wonder if Nova or someone can conjure up the stock spring info for comparison?I guess Hotchkiss should know what's needed, but a strut type front spring operates at a mechanical disadvantage, i.e., it doesn't connect right at the wheel centerline. The leverage is squared for spring rate, so if the spring connects 1/2 way along the control arm, the rate at the wheel is 1/4 of that of the spring. Also, a FWD car has more weight on the front. For comparison, my 3,300 lb. Camaro has ~54% of its weight on the front, and my road race type springs are 600 F and 180 R. Whatever works, I guess!

[philndz]

Quote, originally posted by MadBill » my 3,300 lb. Camaro has ~54% of its weight on the front, and my road race type springs are 600 F and 180 R. Whatever works, I guess!hmmnn...Ive always seen custom race setups to be harder in the rear...but could be different w/ RWD....most of the applications I have studied in any detail were FWD and the harder rear spring rates help to control understeer on turn in.I'd love to be enlightened further...talk on!-Phil

[MadBill]

>Technobabble AlertWell, suspension tuning gets more and more complicated the closer you look, but the simple explanation is that the usual approach is to pick wheel spring rates front and rear which properly support the vehicle and cargo weight (which can be anywhere from 60% Front/40% Rear to 40F/60R) and then tune the cornering balance with the stiffness of the anti-roll bars (which are also called sway bars or roll bars) Too big a bar though causes an uncomfortable ride condition called "Head toss" when you hit a bump with one wheel. This is because the bar is so stiff it lifts the whole side of the car, jarring the occupants sideways. Maybe Hotchkiss' stiffer springs are to minimize the need for a big bar at the rear. Any time you stiffen the springs or bar at one end of a car, more of the resistance to body roll on a corner is generated at that end, which loads that tire more. Since a tire with twice the load can generate less than twice the cornering force, this effectively reduces the grip at this end and increases it at the other. Since virtually all stock FWD cars understeer (i.e. the front pushes out of a turn under hard cornering) Hotchkiss and other tuners would typically increase the rear suspension stiffnes more than the front, thus reducing the understeer, possibly at the cost of a harsher ride at the rear.>End TB Alert<

[shibaman]

You hit the nail on the head Madbill. I already had the Hotchkis sway bars on the car when I went looking for springs to match it. I almost bought the Tien dampers but the cost $1050. and the idea that the Hotchkis springs were better matched to the sway bars convinced me to buy their springs also. No regrets other than on bad roads. On decent roads it rides smoother than stock. It does not understeer!