when to raise tag axle?

[davidbrady]

Hi CC_Guy,

Hish, correct me if I'm wrong, but I think vehicle chassis at a minimum are designed to withstand 3g up at the wheel, 2g in lateral (sideswiping a curb), and 1g in longitudinal (braking/acceleration), with manufacturers typically going higher. With this in mind, the scrubbing forces on the drive and tag should easily be handled by the suspension torque arms. All one needs to do is sight under a Prevost to see the massiveness of the arms and the separation and stoutness of the pick up points; the transverse link of the tag axle is good example.

I agree about upgrading from 315's to 365's except for the case of the 18K lb IFS. I've been told that the new 19K IFS on the X3-45 is an 18K axle with the air springs juiced up to a static pressure of 100psi. IOW's, our 18K axles are the new 19K's, so in this case the 365's are earning their keep. (This is an example of how the vehicle manufacturer, as opposed to the manufacturers of the components, writes the axle load capacity placards and bases the calculation on the system as a whole). This also gives an indication of how much extra GAWR is typically in a given Prevost axle.