Resetting Of Springs

[NEO34]

How come alot of people seem to say that resetting springs is a bad idea, yet there are various reputable companies that reset springs and claim that they don't alter spring rate or the quality of the spring. For example I called the people at King Springs in Qld and they readily reset a pair of their springs (higher or lower) if thats what the customer wants.

I know trucks get their springs reset and granted they are leaf spring but truck suspension is under way more load than any car would be.

Here is an interesting article on the topic of resetting coil springs.

http://autospeed.drive.com.au/cms/A_3082/article.html

Can any1 come up with real/proven reasons resetting is bad especially if you never really intend to take your car to the track and the most you mite consider is a straight line quarter mile?

Just interested in what people think?

[R DIRTY 3]

Some springs can be reset with very little change other than height. Most european type springs like Eibach, Tein, H+R and other various coilover type springs are cold wound and will fail if reset. The heat will destroy the material.

[Sydneykid]

How come alot of people seem to say that resetting springs is a bad idea, yet there are various reputable companies that reset springs and claim that they don't alter spring rate or the quality of the spring. For example I called the people at King Springs in Qld and they readily reset a pair of their springs (higher or lower) if thats what the customer wants.

I know trucks get their springs reset and granted they are leaf spring but truck suspension is under way more load than any car would be.

Here is an interesting article on the topic of resetting coil springs.

http://autospeed.drive.com.au/cms/A_3082/article.html

Can any1 come up with real/proven reasons resetting is bad especially if you never really intend to take your car to the track and the most you mite consider is a straight line quarter mile?

Just interested in what people think?

By resetting a spring what you are doing is reducing its free height, so the car sits lower. If done properly, that’s OK. So when you ask a spring maker if it is technically all right, they will say yes. But the suspension engineer (and experienced suspension workshops) will say no, it isn’t OK.

What you now have is the same spring rate, but with less suspension travel. This means that the car has less capacity to absorb bumps before it runs out of travel. What you feel is a sudden stop as the shock slams into its bump stop. Bump stops are tough (they have to be) so the shock rebounds rapidly away from that contact. So you get a double discomfort in the ride quality, a sudden stop and a fast rebound.

If you do this with standard shocks, which have very limited damping, then the effect is even worse because the rebound is faster. So fast, that it can in effect lift the wheel off the ground. Think pogo stick.

That’s is why, when we are designing lowered springs, we look to increasing the spring rate at the same time. That way the extra rate compensates for the lesser amount of travel.

Hope that made some sense

cheers

[R DIRTY 3]

Well said, and thats without going into the ins and outs of the spring material itself! e.g Hydrogen embrittlement etc etc that does damage the steel over a period of time, meaning that while the car sits right now, 6 months time it will probably just sag...but only as far as the bumpstops

Just my 2cents.