The tandem axle booster mechanism is equipped with a hydraulic relief valve and crush sleeves to eliminate an overload situation. There are 2 shim points on the booster to allow for fine adjustment of the axle grouping height. The tandem booster can be made as a 2+1 variant to be used when there are weight restrictions per axle. Adding another axle (3 axle configuration) will de-rate the unit to 14 500 lbs/axle.