hj60 suspension, OME, one leaf is definatly coming out

dagwill

There are two basic spring specifications that should be considered when buying springs that very few people ever consider or even know about. One is the spring "load' and the other is the spring "rate".

The "load" is the weight it will support at a given height. The manufacturer knows a spring has to support say 500 kgs and they want the body to be X number of millimetres off the ground so they design the spring to hold that weight at that height.

The "rate" involves compressing the spring. It is a measurement of the weight that is required to compress it 1 inch. A 200 kg spring for example will compress 1 inch when a 200 kg weight is placed on it. 400 kgs will compress it 2 inches. 600 kgs will compress it 3 inches and so on. There are also variable rate springs that take a certain amount of weight to compress them to a certain point then more weight to go beyond that point. If the "rate" is too low but the "load" is correct, the car will sit at the right height but the suspension could bottom out easily on bumps. If the "rate" is too high but the "load" is correct, it will sit at the right height but the suspension may not move easily enough and the ride will be too hard.

Your rough ride is the result of the spring holding the car at the required height, i.e. 50 mm higher than stock, so the load is correct but the rate is too high and it requires too much weight to compress it. If you take a leaf out you will affect the load and the car is going to sit lower, which is probably not what you want, but you still don't know what the new rate will be so you won't know how it will ride.

Hopefully the car won't be too low and the ride will be ok but if things are still not right then you will have to take it to a spring specialists and discuss both load and rate.

If the owner wants to give a car a lift and the car is otherwise stock and is carring loads within factory specifications, then the ideal spring would probably be one designed to hold the car up at the new height while retaining the same rate as the original factory spring. Problems can arise when people buy "heavy duty" high lift springs without knowing exactly what they are getting.

Brian