What are these things?
 

http://www.truckpaper.com/images/Tru...e/76124109.jpg

Those extra set of wheels that are not touching the ground... what are they for? Are they outriggers? (Used to keep the truck balanced from tipping over when dumping)?

It's a pusher axle. It's so you can legally haul more weight. 8)

Oh... What does it do? :oops:

Well let's say that truck has a 20,000 lb front axle and 46,000 lb rear axles, that's a gross weight rating of 66,000 lbs. By law you can't go over that. If you load up and your 70,000 lbs, you would be overweight. That pusher axle looks to be a 12,000 lb. Now your gross weight rating is 78,000 and you van legally haul that load by lowering that pusher axle pneumatically to the ground. But each state is different. You may have a gross vehicle weight rating of 78,000 lbs but according to that states bridge law they will only issue you an overweight permit for 75,000.

For instance the company I work for in New York we have a couple walking floor trailers we haul garbage with. Our trucks have a 14,600 lb front axle, 46,000 drives, and 50,000 lb trailer axles for a gross vehicle weight rating of 110,600. But due to the bridge law they only issue us a overweight permit for 102,000 lbs. We could add a axle to the trailer to gross 107,000 lbs but they weight of the extra axle itself would eat up over half of the increase and only give us maybe another 2000 lbs of payload 8) :)

Term
 

I think the terminology for the extra axle to carry more weight is "tag" axle. "Pusher" implies it's a powered axle which it's not. As a previous poster stated, it increases the GVW of the truck. BOL

Re: Term
 

I have always thought that if it was in front of the drive axles it was a pusher and if it was behind them it was a tag axle. I've never seen a lift-able powered axle. Wouldn't be the first time I used the wrong terminology, or second time, third,............. :D

Dont most states put something like 58,000 gross on dump but with a pup trailer the gross goes to 80,000?

I can haul 80,000 with a tri-axle in Ky....legally. Indiana it's only 68,000 :roll: . I don't know why some companies use tractor trailer dumps. Those are scary looking when they dump.

Yea but when they fall over....its slow and cool :roll: I drove for a company local pulling a 22' dump....only fell over once, and yes....its a tag axle where I'm from.

We call them pusher axle's here.