Spring Tuning Set - Rates

[Dave Treacy]

I have the Spring Tuning Set and would like to know what the lb rates are for the springs. The rates given on the sheet that comes with it provides rates, but not in lb (dunno what it's in...)

What I'm mainly after are the rates for Blue, Red and Yellow.

[MattW]

I'll be honest with you Dave, I was always under the impression that the Rate was in lb/inch.

[Dave Treacy]

I thought so too Matt, but then compared them against Associated and Hudy springs. They are very close, but the Suhumacher ones are waaaaay off..

Not a scientific test, but measured compression against a constant weight (tin of beans!)

[MattW]

In what way do they seem different???

[Dave Treacy]

OK, yellows are supposed to be 25lb - so are Associated Coppers and Hudy Dark Blue.

Measure the compression (see bean test above) - and the Schuie springs compresses more...indicating a lower lb rate (maybe 22lb?)

[MattW]

Dave (I'm hoping someone who knows more about this is going to help me out a bit!!) However i have what i believe to be a rough understanding!! I think it is all down to the length of the spring. A shorter spring of the same "rate" will always be stiffer than a longer one. The measurements used usually relate length - i.e lb/inch, which is why it is very hard to try and compare different manufactures springs.

[Badger_Ben]

Dont believe the length of the spring should make a difference, as surely if a spring is 22lb/in, it should still compress at the same rate, otherwise you need to be including the length of the spring into the rate equation.

On a lighter note did you change the brand of beans or is that the well known spring beany constant :D

[Dave Treacy]

Nope, it was the bog standard 57 variety....

[mark barord]

There was a page on the CML site that had all the available springs properly measured and rated. I downloaded it a couple of years ago but I am sure it will still be there.

[Matt Bridge]

There is a spring rate chart on the macc track website. You will find most of the top schuee drivers use associated springs on their cars. Due to the powder coating on the schuee springs it is hard to find an equal pair and also the coating adds some tension to the spring and as such can mess you up a bit. The associated springs are painted so do not have this proble. The IRS springs fit also

Matt

[Tim Branigan]

From what I know of springs in full size race cars the spring rate 22lbs/in means that for the spring to compress one inch a force of 22lbs is needed. What you are saying Dave is right. You must know the starting length of the spring and then measure the finished length of the spring. As most of the springs are linear it is possible to work out what the spring rate is in lbs/in using just a couple of pounds wieght. On the full size cars the matching of springs in both rate and length was critical. Maybe someone can make and sell a tool for the touring car springs.