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Damper potentiometers vs laser ride height sensors

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Greetings everyone,

I am considering my next move on my data logging project using a Plex SDM-550 dash. Now that I have the basic sensors covered I would like to tackle suspension & aero logging/analysis.

Would you recommend to buy first a set of 4 damper potentiometers or 3 laser ride height sensors?

There is no rule limitation on what to use...



Are you wanting to measure ride height or suspension position?

Rotary potentiometers are relatively cheap compared to the linear units, and have a high resolution (this also depends on the ability of the device logging the data) and will inform you of the rate of change of the suspension position. From this information you can determine if the damping and spring rates are correct for your vehicle. You can also look at the trend in the suspension positions over time (i.e. accelerating along a straight) to see if the suspension is compressing (or expanding if the aero is incorrect) under the increasing aero loads being applied. If you have the motion ratio and accurate rates for the coils, then you can work out the extra load being applied by the aerodynamic devices. You cannot determine the amount of tire squish that is occurring at the same time with the load being applied.

A laser ride height device/s will provide you with data of the vehicle ride height at the locations of the sensors, but without knowing what is happening with the suspension it is difficult to determine what the changes in ride height are caused by.

Thanks Stephen, the aim is to understand more what the suspension is doing so I can tune the mechanical grip and then apply the aero package.

From your response my understanding is that you recommend to get rotary potentiometers as a start.

Hi Andreas!

Thanks for your thoughts, Stephen!

If you're interested in tuning the suspension then being able to measure the suspension displacements is going to be important. Whether you use linear or rotary sensors will depend on both your budget and how much space you have available to package them.

The Delphi ER10031 sensor is a cost-effective rotary option for a lot of people and worth considering.

You can do a lot with suspension pots, so I would say this is a great place to start expanding your logging setup!

Thanks for the great feedback Tim.

I will focus on the pots first.

much appreciated,


Also, I should mention that our Advanced Data Analysis course (which is targetted for release by the end of March) contains a lot of information on setting up damper pots and using the outputs for chassis and damper tuning!

A some comments about ride height Vs suspension travel.

Depending on what you're using the vehicle for, there may be some inconsistencies between travel and height - for rally/public road events some countries use a lot of road camber in some places which will affect the apparent ride height, and riding kerbs will also increase the apparent ride hight.

The second thing is it the surface is bumpy or has creasts, it's possible the suspension will fail to follow the terrain either because it isn't reacting fast enough, it doesn't have enough travel, or both.

There is a third variable - tyre deflection is going to give different results, as the effective radius is going to change with loadings.

If you have both, and apply them intelligently, you're going to gain a lot more information than if using only one method.

Thanks both, looking forward for the advanced caourse... I am in the middle of the introductory one.

Regarding having both, I am restricted by cost unfortunately. This is a self funded circuit racing project and car. So the budget is not infinite...

Andreas, laser ride height sensors are definitely at quite an advanced level so I would not worry about these at the moment. You will get more value out of damper potentiometers at this point in your learning and car development! 💪

Thanks Tim

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