So I was doing some research and people were saying than the front and rear spring rates should be different? It seems to have something to do with motion ratio and under/oversteer, but how exactly are they affecting the spring rate? Thanks in advance.

  • What year / make / model are you trying to repair or maintain?
    – cory
    Jan 18, 2017 at 19:22
  • I'm in a solar car team and we currently doing some research for the next model so I'm just looking for some general information here. Jan 18, 2017 at 19:26
  • 1
    Could it be to do with the fact that most cars don't have symmetrical front/rear weight distribution?
    – BadAtMaths
    Jan 18, 2017 at 19:29
  • That's true it probably has something to do with weight distribution. But would there be other factors though? Jan 18, 2017 at 19:34
  • Other factors might be that the front wheels turn on most cars. Also, weight shifts to the front on braking and to the rear on forward acceleration. The suspension height might factor into things. Rear of vehicles usually being a touch higher to allow for cargo. Front, rear, 4wd, AWD drive layouts may also matter. We can speculate all day long though. I'm not sure you are going to find vehicle suspension engineers here though.
    – cory
    Jan 18, 2017 at 19:44

1 Answer 1


The primary reason is the weight distribution of the vehicle. Vehicles tend to have a big heavy engine up front and not much weight in the rear. The ratio should be closer on vehicles with close to 50/50 front/rear ratio. Vehicles with engines in the rear should have higher spring rates in the rear.

From http://polybushings.com/pages/handlingtips.html:

To increase over steer - softer up front, stiffer out back
To increase under steer - stiffer up front, softer out back

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