-
Truck Question
I've seen some trucks (such as dump trucks) with an axle that can be lifted up and down. My question is, what is the point of that? If they left it down all the time, why couldn't they just keep it down? What would be the reason to engineer that into a truck? If they kept it a solid axle, wouldn't that decrease the complexity of the truck itself?
Also, would it count as an extra axle when it's down (say when paying toll for a bridge)?
-
If you are talking about a semi or articulated size truck, then it is done for a few reasons. Without load having all wheels on the road would cause it to bounce from the rigid suspension. Lifting wheels saves tyre wear especially when turning, and makes it easier to turn. Most lift axle manufacturers state it is maneuverability.
If you are talking about a mining or large dump truck, it is so the axle can be raised to change tyres.
A solid axle would cause the truck to lose traction under undulating surfaces, and would also bounce around, being more unstable to drive, such as used in a bobcat.
I think the first reason is what you are after though.
-
no, he's talking about like this... and i have no idea. i know they put it down when loaded, but it never made sense to pick it up to me.
[IMG]http://www.flexleasefinancial.com/2006%205900%20International%20Dump%20Truck%201%20MVC-001S.JPG[/IMG]
-
Certain laws require a set number of axles that depends on the weight of the load. If the weight gets to be too heavy then they drop the extra axle down to compensate. Otherwise they just keep it up. This is what I was told anyway.
Found this too: [url]http://auto.howstuffworks.com/question26.htm[/url]
-
Thanks for the answer.
So then when the axle is lifted up then it counts as one less. That's cool. Now I see the sense in it. :rolleyes:
-
in canada, the trucks have 22 wheels as opposed to our 18. increase drag but increase the distribution of the load. maybe for toll purposes u pay less.
-
I checked more manufacturers of these axles and they all state that it is for easier maneuverability. And I would expect lowering them would to be able to carry heavier loads. There is a load limit per axle.
-
In the EU there are laws that say that axles may only carry XXX Tuns of weight. Reasonable thinking says it is to save fuel and money :)
-
1 Attachment(s)
[QUOTE=cmcpokey;668899]no, he's talking about like this... and i have no idea. i know they put it down when loaded, but it never made sense to pick it up to me. [/QUOTE]
This might be another example, it is the standard heavy truck of the Dutch army form the fifties and sixties, the DAF YA328.
It is a 6x8 truck, and the rear axles swing around a central drive train.
The second axle is purely an idler and cannot be lowered. It just helped to pass terrain difficulties.
-
Some cars have wheels off the ground too.....
[IMG]http://i84.photobucket.com/albums/k6/revetec/capriwheelie.jpg[/IMG]
Sorry just being stupid!
-
lol well that is some lift...wouldn't want to see the rear fender after that
-
[QUOTE=henk4;669068]This might be another example, it is the standard heavy truck of the Dutch army form the fifties and sixties, the DAF YA328.
It is a 6x8 truck, and the rear axles swing around a central drive train.
The second axle is purely an idler and cannot be lowered. It just helped to pass terrain difficulties.[/QUOTE]
Could it also help it from being high centered?
-
[QUOTE=NSXType-R;669268]Could it also help it from being high centered?[/QUOTE]
Thats exactly what I was thinking.
-
[QUOTE=revetec;669072]Some cars have wheels off the ground too.....
[IMG]http://i84.photobucket.com/albums/k6/revetec/capriwheelie.jpg[/IMG]
Sorry just being stupid![/QUOTE]
Stupid old muscle cars, these days we have cars that can lift both axles off the ground.
[IMG]http://www.rally.lv/Bildz/Th_MarkkoJump_2.jpg[/IMG]
-
1 Attachment(s)
[QUOTE=NSXType-R;669268]Could it also help it from being high centered?[/QUOTE]
I am not sure what you mean by that. I have added a picture of my mount during my times of military service and it has exactly the same drivetrain (6x8) while the idler is in the same position as the other wheels and could not be lifted.