now wile writing this I know im going to get shot down and probably by a tank .
Traveling from Adelaide to Mannum today I followed a van behind a Toyota cruiser . Not to fast not to slow sort of sitting ok level wise . Now Im an ex plant operator and its in my blood to look for things going wrong .
im not going to say this IS that cause of a lot of van crashes happening lately . Im asking COULD this be part of the cause and I know not all crashes ARE Im saying a FAIR percentage are . Have a look at face book .
Not I was watching this van in front and floundering along a not so smooth road I noticed the front of the van moving ever so slightly sideways in turn pushed the back of the van the other way . Now this happened nearly every time he/she went through a dip .
Now this got me thinking hmmmm why . Loose towball or hitch maybe tow bar dont know what it was . He didnt answer the radio and the road was not a good road to pass on so I did my best to get this guys attention . Not until he stopped was I able to tell him what I was seeing and sort of told me to mind my ow business . O well I hope I never come across him again broken down or what ever .
Not this is were i got to thinking . The Toyota had been lifted now again Im NOT saying this IS the cause Im saying COULD this be the cause . COULD a lifted boil sprung rear end with a standard pandard (spelling ?) be throwing the van 1way enough to cause it to sway turning it into an uncontrollable sway finishing in a crash .
Yea yea I know what some of you are thinking . This clown wouldnt know what he is talking about . Think what you want I know what I saw and Im just asking what others think . Having built and involved in build a few serious off-road race vehicles and with a serious lift it can throw the vehicle body out ov alignment with the wheels if it has coil rear end .
Maybe I should elaborate to how I came up with this idea . Now coil rear end cars have a rod called a panda rd or panahard Im not sure on the correct spelling . Its connected from the vehicle chassis to the diff . It keeps the vehicle from swaying from side to side on the diff .(ever seen a v8 touring car swaying from side to side and the wheels stay in one place . Now as the vehicle springs up and down and this rod does push the car sideways maybe in a small scale but with the extra weight of all the gear in the back and the weight of your van on the ball it maybe could Im not saying does Im asking what you people think COULD IT .
I don't think it is that noticeable as to sway the van that much as Panhard rods do a good job (not perfect - see diagram below). Could be they are going through dips on an angle and optically you see this, OR flatish tyres (I mean lower pressures than required will allow degree of sway as well).
I know those roads well and hard to blame Panhard rod per se IMHO.
As an example I have 3700 GVM and 2.3 tonnes on rear axle at times, and Cooper old tyres needed 50-55 PSI and now Bridgestone need 60 PSI to be laterally stable. If inflated too low I can feel the sway. Same with van too low a pressure = more sway, in general terms.
PANHARD ROD arc
PS Meant to say a lift of 3 inches plus is generally accepted as needing an adjustable/new Panhard rod
-- Edited by Baz421 on Monday 11th of December 2017 11:06:51 PM
-- Edited by Baz421 on Monday 11th of December 2017 11:09:01 PM
You are most likely on the money mr glasses my experience with pan hard rods is if you do a lift you have to adjust the rod to suit or else you have sway problems i had that problem with a toyota cresida years ago
I don't think it is that noticeable as to sway the van that much as Panhard rods do a good job (not perfect - see diagram below). Could be they are going through dips on an angle and optically you see this, OR flatish tyres (I mean lower pressures than required will allow degree of sway as well).
I know those roads well and hard to blame Panhard rod per se IMHO.
As an example I have 3700 GVM and 2.3 tonnes on rear axle at times, and Cooper old tyres needed 50-55 PSI and now Bridgestone need 60 PSI to be laterally stable. If inflated too low I can feel the sway. Same with van too low a pressure = more sway, in general terms.
PANHARD ROD arc
PS Meant to say a lift of 3 inches plus is generally accepted as needing an adjustable/new Panhard rod
-- Edited by Baz421 on Monday 11th of December 2017 11:06:51 PM
-- Edited by Baz421 on Monday 11th of December 2017 11:09:01 PM
So what was causing the different movement at the front of the vanto the car
Why the watts link is better . But they ALL reguire good geometry . Your possibly right the 10 to 20mm radius movement is exaggerated through coupling, van etc . Maybe a little balance ? Yes some out there can be so grumpy !! But the friendly nomads MORE than make it up . Talk to people your a silly old havachat .. Keep to yourself ? Your grumpy old codger ! Ahhhh !!
When you think about it, the porpoising action of the noise down tail up and then the reverse would cause the body is moving side to side compared to the axle, multiply the effect by the distance from the axle to the tow ball and that side to side movement could be enough to start a feed back loop where the tail starts wag the dog with both the up and down movement and the side to side sway. Once the rear axle is unloaded enough by a lift and a sway occurring at the same time all control is lost, the van starts driving the car. The porpoising itself is bad enough, a bit of sway can be handled, but the 2 combined and feeding back between each other could create a situation where these actions take control away from the driver, all caused by a poor suspension design.
T1 Terry
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I don't think it is that noticeable as to sway the van that much as Panhard rods do a good job (not perfect - see diagram below). Could be they are going through dips on an angle and optically you see this, OR flatish tyres (I mean lower pressures than required will allow degree of sway as well).
I know those roads well and hard to blame Panhard rod per se IMHO.
As an example I have 3700 GVM and 2.3 tonnes on rear axle at times, and Cooper old tyres needed 50-55 PSI and now Bridgestone need 60 PSI to be laterally stable. If inflated too low I can feel the sway. Same with van too low a pressure = more sway, in general terms.
PANHARD ROD arc
PS Meant to say a lift of 3 inches plus is generally accepted as needing an adjustable/new Panhard rod
-- Edited by Baz421 on Monday 11th of December 2017 11:06:51 PM
-- Edited by Baz421 on Monday 11th of December 2017 11:09:01 PM
So what was causing the different movement at the front of the vanto the car
dibs
I thought I gave a couple of examples,,,,, also poor driving technique,,,, distance of towbar from centre of effort/axle - mine is Reece and sticks out about 300mm from receiver and about 1.5m from rear axle - therefore any MINOR steering input influences movement at front of van AND IT CAN BE VERY PRONOUNCED),,,,, power steering problem (trucks were often hard to drive straight - either went slightly left OR slightly right no centre)
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Why is it so? Professor Julius Sumner Miller, a profound influence on my life, who explained science to us on TV in the 60's.
