Lift Axles and Lift Axle Controls

Yes the controls must be outside of the cab if you have adjustable axles, at least in MN, GA and many others.
Any axle that is liftable on a tractor cannot be used in Alberta. They make you chain it up. That is why many oversize haulers have gone to a tri drive, 3 drive axles to carry the weight in Alberta. States vary on the rules, so you must check with each one you will be traveling through on the lift axle controls.

 

cali you have to certify the truck. and there are specific requirements that have to be met on how it is plumbed. Missouri must be outside. Oklahoma outside. lousiana outside. that I know of. I plumbed mine up so I can control from in or outside of cab.

 

a lot of heavyhaulers have them plumbed inside. personally I prefer inside. makes turning tight corners and slick roads manageable. one way that is easy is to plumb outside and install an electric dump valve with a switch inside to dump the air. it wont lift it but will be handy.

 

I know in MO and KS most people have the regulators outside the cab, usually under the door. Everyone runs the lift/dump switch/valve in the cab.

 

Ohio used to require them to be outside but they did away with that in 08.