Only been driving Class 2 a few weeks, so learning very fast.
I have a question about rear axles.
Yesterday had a job on a Scania 26 tonner which had a double axle at the back.
I drove with the rear wheels raised & was wondering when they have to be lowered? I noticed what looked likea switch (green) to lower them. Also noticed what looked like a weight dial (not sure if that’s correct.
Does it do it automatically when a certain weight is reached ?
Or is it something that’s left to drivers discretion?
keano1:
Does it do it automatically when a certain weight is reached ?
Depends on the truck.
keano1:
Or is it something that’s left to drivers discretion?
To a point. In theory if your gross weight is over 18t or the axle weight on the other rear axle is reached due to there being a lot of load above it then you need the third axle down. If neither of those are the case then it’s up to you, but the sensible thing (in terms of tyre wear and fuel economy) is to leave it up.
I tend to leave mine down unless I’m really lightly loaded, but that’s because of the nature of our goods and the diminishing load and weight of the crane could mean the axles get overloaded.
It makes it easier to manouevre, but it will self lower if the rear axle would overload. However I have loaded about 10t in the yard with the weight more towards the front and the axle didn’t automatically lower, so you could overload the front or both.
Running with it down when lightly loaded doesn’t do much for traction in the wet though.
Personally if the truck I’m driving has any axles that will lift then I will leave them up as much as is legal as you’re saving rubber and saving fuel having them up.
As above , if the weight will allow the axle to be legally lifted , then I will lift it .
Gets the fuel economy up , company having a purge on it at the moment .
Andyroo:
I tend to leave mine down unless I’m really lightly loaded, but that’s because of the nature of our goods and the diminishing load and weight of the crane could mean the axles get overloaded.
If in doubt leave it down I’d say.
Just to add ours are steered midlift axles, so the turning characteristics are roughly the same up or down…i.e. terrible!
i remember asking the same question when i did a shift at the co-op driving the longest class 2 i have ever seen. Over 30ft long scania, i instinctively raised the axle after my last drop, but when the gaffer saw me coming back into the yard he told me to always keep it down as the overhang is actually ILLEGAL with the lift axle up. Duno if he was right but i always keep it down now at the co-op
Andyroo:
Just to add ours are steered midlift axles, so the turning characteristics are roughly the same up or down…i.e. terrible!
They need a bit more room, but turn the wheel and the wagon will go that way in almost any conditions.
My heart’s been in my mouth on more than one occasion driving tag or non-steering mid-lifts fully freighted. This was several years ago…
It’s either not so noticeable with air suspension on those axles, or I’ve got used to it now. But when I started driving artics on three axles it seemed quite common. Because your second and third axles are fixed, pointing straight ahead with a lot of weight on them. When you turned the wheel, those two axles keep you on a straighter course than you’d expect, against the amount of turn you’d put on the front wheels. This used to happen on wet or dirty roads (or wet and dirty), they were fine in the dry. I don’t notice it now though.
I’ve noticed it recently on an Axor unit I’ve driven. It steers noticeably worse with the middle axle down especially when you’re loaded up to near the maximum.
From a tip i received on this site i leave mine up if the truck feels it needs them down they will go down.
I have had one ridged put its axle down purley because it was on a bouncy country lane & NOT overloaded.
On the Artics if the truck puts the axle down I lock it down till I need to manuvere on to the bay.
