ronarndt

I have Koni yellows with adjustable spring perches- threaded Tri-Point Engineering installed, not the stock Koni ones- and Hypercoils.
With my car jacked up so wheels are off the ground, I have the spring perches adjusted so that the springs have no slack/free travel. This makes the static height at each corner one inch higher in the front and the same in the back as stock height with wheels on the ground. If I lower the spring perches to lower the car, this leaves slack between the top of the spring and the upper spring seat while the car is jacked up and the suspension fully dropped. I realize that this slack will be taken up when the car's weight is placed on the wheels. The shocks will not allow the suspension to immediately drop and cause slack. However- are there any conditions where driving conditions could allow the spring to have slack/space between the top and the upper spring seat? Seems this would be a real unsafe condition. Other than the car going completely airborne, I can't think how this would happen. Opinions???
Ron A.

maxcooper

It won't happen in driving, unless you drive off a cliff. You may need to be careful when you work on the car to make sure they seat correctly, but it hasn't been a problem for anyone that I know of.

-Max

DamonB

Sure it will, but probably not on street tires. I have seen plenty of cars of all types lift the inside front wheel under power on corner exit because the suspension goes into full droop. Once your off the spring the car has to "fall" before the spring does any work again. IMO there's no excuse for not running the proper length of spring. The spring should never leave the perches.

This pic is with race tires accelerating out of a sweeper. The inside front wheel is off the ground because it's in full droop. If the spring were out of the perch at this point that corner of the car is not going to settle properly because as you know only the springs support the car, so that corner will build up momentum as it falls back onto the spring and will take longer to settle back to normal ride height. Hopefully there's not a hard braking point right after that which will crash the car down onto the bumpstops.... My car is at stock ride height, it's hunkered down so far strictly from the cornering forces.

ronarndt

DamonB- In this case, I don't think shorter springs will help. I would still have to raise the spring perch to make contact with the shorter spring and the ride height would remain roughly the same. I need to have the struts shortened to limit the droop when un-weighted. This should allow me to lower the static height and still have the springs make contact with the upper seat when the car is jacked up. I bought the current setup from someone who had 19 inch wheels and needed the full suspension travel to prevent rubbing. He had the length of the struts changed (shortened, I thought he said) at Tri-Point. But I believe you are right about keeping the spring in contact with its upper support. I keep imagining the spring slamming down an inch or two and not getting in correct register immediately. During that time the handling would probably be un-stable. Considering the cornering force and speed needed to unweight the wheel in the first place, this would not be a good time to be in the car, unless there is a lot of recovery room on the side of the road. (Or "recovery room" at the local hospital).

I have heard about people complaining about their lowered suspensions "falling off the spring perches" when they jack the car up to work on it and was curious how others handled this problem.
Ron A.

DamonB

Right. Nobody ever does it but that's the correct way to do it if spring length alone can't solve the problem.

Tripoint can shorten the struts for you. Essentially you just cut off the end of the shaft and machine it once again.

ronarndt

originally posted by DamonB:
Or as they do in this here part of NASCAR country- chop off the end with a hacksaw and spot weld an old washer on the end.
Thanks for your advice. Ron A.