hi i have a few questions i was wondering if you could answer
what does pusher axle mean
what does a tag axle mean
why do some wagons have a mid lift and some a rear lift
All these terms refer to 3 axle tractor units.
Push axle: means the driven axle is the rear most axle. i.e. It is pushing the truck fowards from the rear.
Tag Axle: This refers to the rear most axle (often has single wheels), when it is a lifting axle. So the mid axle is the driven one.
So called, because they were often retro-fitted as a means of getting the then very high (£3500?) road tax down, rather than coming from the factory like that. So, the rear most axle was “tagged on”.
The 3rd option is when neither axle lifts, but the mid axle is also a steering axle along with (obviously) the front one…and just to confuse you, some even steer and lift.
The main reason for making axles liftable is to save on tyre wear, particularly when turning sharply such as when manouevring in tight yards. (If you turn on full lock with a mid-lift axle down, you will notice that there is a lot of sideways “drag” on its tyres.)
Also to obtain traction on greasy road surfaces.(by putting more of the trailer/load weight onto the drive axle).
As to why?
Tag axle explanation above goes some way to answering.
Long wheel base units (pushers) tend to give a smoother ride with the axle up, especially if solo. However, a tag axle unit is much more manouevreable with the axle lifted as the wheel base then becomes very short. (easier to reverse trailers into tight spaces when you have limited room ahead of you).
Sales of 3 axle units have fallen over recent years since the re-aligning of road tax bands, but they are still necessary to run at 44 tonnes.
I’m sure there will be other reasons for different companies specifying tag or pusher, & some of the other members of Trucknet will doubtless list them below…
thank you for your reply