Ask The Editors: Shock Spring Rating

They play a role but it’s probably not what you think.

That’s a good point – a lot of riders fail to realize how important chassis design and suspension spec really are in making machines that weigh so much stable, plush and manageable. Except here’s the catch – the rating of the shock spring itself is only one variable in a very complex chain and, it doesn’t exactly mean what you may think.

In fact, it’s so insignificant in the overall formula that you’d be hard pressed to find it listed – even on aftermarket spring kits. Why? Because you’re getting a minimum of dual rate spring design – which means whatever number it starts at quickly ramps up as the spring is compressed. And nobody says this number has to stop there – some designs change multiple times as the suspension moves through its travel.

This is smart because the forces enacted upon the vehicle are very different at low speed in a straight line are completely different from the ones you’re dealing with in a high speed, choppy corner.

Next – the spring itself’s primary function is rebound. The gasses and/ or oil inside the shock body handle smoothing out the terrain through the damping process. The spring’s job is to return the shock to its full travel after compression. Now it is true that a stiffer spring can aid the shock in resisting bottoming / cutting down on body roll (after all, they are carrying some of the vehicle weight as well), it’s important to remember that the spring itself is not performing the actual damping.

Lastly, and we recently dove into this subject here, shock linkage plays its part in the process by the altering the leverage ratios enacted upon the suspension. This is why every inch the wheel moves doesn’t necessarily eat up an inch of suspension travel.

All of this said, taking a look at race trucks around the same weight, the number you were initially asking is probably something to the effect of 500 lbs/in – meaning 500 pounds of spring resistance per every inch of its travel.

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