That's great, but what happens when you change to springs of a different manufactuer? The Losi springs reported rates are consistent with one another, but they aren't equivalent to how they are rated by AE, or Kyosho, or Yokomo. How do you handle that?

I believe you misunderstood what I wrote. What I'm suggesting you do is actually rate your own springs on your own car, which is what Fred is suggesting, but I'm taking it a step further. This will require you to do your own work and create your own data. So, let's go back a couple of steps and recap.

Fred is suggesting you find a set of springs with matched frequency by observing their frequency during testing.

I am advocating you find a set of springs with matched frequency by measuring wheel rate, and then doing the calculations to figure out the frequency (which is related to shock mounting position, spring selection, and the amount of dead weight you have on the axle you are measuring) and then verify your data by using Fred's method to ground truth your work.

When I attempted to use Fred's method, I realized it would work but it didn't give me any empirical data that I could refer back to. Lets say I got four sets of matched springs at different stiffnesses. While I know which is softest and which is stiffest, how do I how how soft and stiff they really are? And how big are the steps in between?

Now we can start asking other useful questions while we're at it, like how much does moving a mounting hole over really change things? Did I make a mistake in measuring because I find an inconsistency in the data, or is there something else going on? And then it occurs to you that once you figure out how to measure your chassis, you can go out and measure any other chassis of any other manufacturer and bring that setup over to your totally different chassis - and with your data book, you can do it right now.

The downside is it requires a significant amount of testing and data collection on the bench. My first dataset took about 30 hours to measure. These guys are using the same method to measure the stiffness of sway bars, but how you would figure out the wheel rate is exactly the same way.

http://www.circletrack.com/chassiste...s/viewall.html

What I'm doing now is calculating how adding/subtracting weight or moving it changes wheel rate and frequency. We commonly refer to that as moving the battery. If you need a chassis to 'cut' harder entering the corner (like a hairpin), you move the weight back. If you need it to have more constant arc grip (like a sweeper) you move it forward. But that also changes the spring frequency - if you can measure it, you can account for it, and make changes accordingly.