AZScout wrote:
Can someone in the know educate me on the ins and outs of springs? Specifically, and this was alluded to in another post, why does the HD OME springs have more poundage yet sag when weight is applied as compared to the CRD springs?
Hmmm. Dave there are numerous things that cause a vehicles' suspension to lose ride height, but just remember, the springs may not be 'sagging' because in 99.9% of all cases, if you remove the extra weight you put on, you'll find the vehicle will most likely go back to the original lifted ride height.
The KJ like all IFS 'coil over' type suspensions' are particularly suspeptable to ride height loss from adding weight as the suspension design works on an approx 2:1 ratio of load. The coil over itself sits inboard somewhat, and the physical size of the coil isnt that huge in comparison to say a Toyota 80 series Landcruiser, or Landrover for instance, therefore they make the coil with heavy gauge wire and put some 'rate' into it.
Take this example:
The stock KJ CRD coil is around 400Lb.
If the KJ had a front suspension that was exactly the same as say an XJ or TJ, the spring rate would probably be closer to 220-250Lb as the design doesnt concentrate the load as hard on the springs as the IFS design does. Basic mechanics / physics applies to additional weight too. If you put a 50Kg Bull Bar on the front of your KJ, the weight imposed on the coils/suspension would be around 100kgs extra, therefore causing the car to lose ride height.