I'm trying to find a suitable shock absorber for a small ATV with a specific value (to be determined later). But everywhere I look, no one seems to be giving the damping ratio of the shock absorbers. I'm not expert in this field, so I'm wondering if I'm missing something, and that in reality I don't need the damping ratio to select a proper shock absorber, and that the damping ratio in fact can be controlled by some other means?

All I have is the intro to vibration degree course where the damping ratio was always given.

Thanks for the help in advance.

  • 2
    $\begingroup$ The damping ratio is a parameter of the complete vibrating system, so it depends on the vehicle mass and the spring stiffness as well as the damper. The specifications should give you the damper force for different compression velocities, and for a "good" damper the relationship will not be linear as it was in your "Dynamics 101" course problems. $\endgroup$
    – alephzero
    Commented Aug 16, 2019 at 13:09
  • $\begingroup$ Also the compression rate will not be the same as the extension rate... $\endgroup$
    – Solar Mike
    Commented Aug 16, 2019 at 15:00
  • $\begingroup$ Can you even buy shocks by the damping rate, without being an OEM? $\endgroup$
    – TimWescott
    Commented Aug 16, 2019 at 19:35
  • $\begingroup$ @TimWescott well we had fun choosing shocks for a Fiat Chroma and selecting between various options aka rates but that was a while ago... And there are shocks available which have adjustable damping that is user controllable... $\endgroup$
    – Solar Mike
    Commented Aug 16, 2019 at 21:14
  • $\begingroup$ I actually started an answer, basically suggesting that if ATV shops sell variable rate shocks to get some and experiment. But I figured I don't know enough about this corner of engineering to count as an authority. $\endgroup$
    – TimWescott
    Commented Aug 16, 2019 at 22:03

1 Answer 1


There are several companies that make adjustable dampers, of course, how much you want to adjust and also how much you want to spend are parameters that only you can decide.

Companies like Bilstein, Spax, Fox and TFX can provide solutions based on the mass of the vehicle and the travel in a non-adjustable solution all the way to twin shocks with separate reservoirs with landing and extension rates controllable differently.

Fox can be found here

And TFX here.

There are others, but that should give you some directions to check out.


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