APU Weight Exemption on Which Axle(s)?

it doesn't say.

 

Since most of the apu I see are mounted by the catwalk. I would think.most of that weight would go on the drives

 

Maybe it is for gross weight?

 

I do believe it is gross. Just has to be legal on axles iirc.

 

The federal suggestion states axle or gross. It really doesn't matter which axle, as long as you are not going over the mechanical limit. I.E. you are still limited to 12k on most fleet trucks as that is the axle weight. 12.5k and 13k for some trucks, again depending on the physical axle.

Here is a list by OOIDA of which states allow how much weight. Also, make sure you have the weight certification in your paperwork. That's what allows the exemption.

Vehicle weight exemptions for APUs, Owner-Operator Independent Drivers Association

 

Most fleet trucks the steers are 12k yes. At least everyone I've ever been in.
The drives, on the other hand are typically rated for 40k (20k per axle). It's just Interstate system limits to 34k. A lot of states allow more on state roads.

 

my steer axle is rated at 12,300