Dump truck spec question

Have room to add drop axle?

 

If you stretch it I would consider it.

 

You never originally said that. That's why the weight was confusing.

 

Standard weight allowances would be 34,000 on the tandems, 12000 on the steer making you legal for a 46,000 pound gross. Im guessing that you have 40,000 lb tandems, which is common...but that doesn't mean that its legal to load em to 40k. Tandems are genrally considered legal at 34k.

You could stretch enough to add a lift axle. A 225-235 inch wheelbase generally works well for a single lift axle....measured from center of steer axle to center of the rear drive axle. Here in AR, they used to allow a full 17,000 for the lift axle as well as long as you weren't on interstate roads...not sure about now, but I think they still do. The 20k steer axle will only gain you 8k in gross, it will drive a lot worse...and you still have to find a way to get weight on that 20k steer axle. The lift axle should allow quite a bit more extra payload than a heavier steer axle.

 

Might want to check and see if you need a 2nd steering box/assist cylinder with the heavier front end. IIRC its required on steer axles here that are over 18k lbs.