Originally Posted by Razathorn

Did some AE big bore spring rate tests and determined that the rears are pretty close to the advertised rate, but the front springs are significantly stiffer. I only had a handful of springs to test from a friend. The rear black, green, and white spring rates are pretty much what they claim for the rear, but the the front browns came in just at 3 lb/in, where as they are supposed to be 2.85. I don't recall the rates for the other fronts I tested (as I was doing a LOT of springs, hunting for the softest fronts I could find at the moment from kyosho and losi), but the general theme was that the ae front springs got stiffer as you went with the stiffer colors, but all significantly stiffer than their packages indicated by around .1 to .2 lb.

This basically confirms empirically that you really can't trust spring rates claimed by manufactures. They get the "hey this spring is stiffer than this one" right, but that doesn't mean that they're what they claim *exactly*.

I also tested my old SMALL bore springs and found the following:
green rear 1.9 claimed, 1.9 measured
brown front 2.8 claimed, 2.8 measured
silver front 3.85 claimed, 4.0 measured