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Swaying whilst towing

Posted: Tue Jan 03, 2012 12:24 pm
by deonengel
hi everyone, all the best of the new year to all :D
i truly hope all had a good rest.

:roll: i had a VERY scary experience whilst towing my caravan to marakele recently whilst overtaking a large low bed truck :shock: . - my caravan started snaking viciously from side. i always thought that the towing stability was not the same as my old isuzu kb320 :| .- this was not new - but never so pronounced (ek het my g@t af geskrik :o )please if anybody can help i will appreciate it very much - can it be the rr? or frt? stabilizer bars, or what else - i at this stage deem the vehicle UNSAFE to tow :?

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 12:29 pm
by deonengel
:oops: ohhh yeah the vehicle is a 2001 gen 3, 3.2 did gls lwb with 230 000 km - sorryyy :roll:

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 12:38 pm
by 4ePikanini
what was your tyre pressures (car and caravan)?
what was the ball weight?
did you use a stabilizer?
what was the wind conditions?
when was the last time you checked your shocks?

Best thing to do with swaying caravan or trailer is to accelerate and correct with small slow movements.

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 12:40 pm
by dr0ne
Hi deonengel,

There are a few basic things to check first.

Are you towing nose down on your caravan/trailer?

What is the weight on your tow ball? (Easy to check with bathroom scale under jockey wheel)

Tyre pressure of rear car wheels.

How is the load distributed in the caravan/trailer? Always have a heavier load infront of the axle.

It's easy to fit a stabilizer and hide the problem, but there must be something else causing it. Rather look for that first.

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 1:57 pm
by 4ePajero
i at this stage deem the vehicle UNSAFE to tow
I would rephrase that to say that the "combination is unsafe at this stage".

The unstable trailer / caravan can be due to one of the following causes:
  1. Tow vehicle
  2. Trailer / caravan
  3. Hitch
  4. Speed & External conditions
1. Tow vehicle.

The following can cause unstable towing:
  • Tow vehicle to light for the trailer.
  • Incorrect / uneven tyre pressures
  • Tyres with to soft side walls
  • Worn / too soft shock absorbers
  • Play in suspension components eg track bar bushes
2. Trailer:
  • Incorrect load distribution
  • wrong tyres
  • incorrect / uneven tyre pressures
  • Worn suspension components
3. The Hitch:
  • Too much weight at the back of the trailer
  • Too little weight on the tow ball (load it to the legal limit. If the suspension can't cope with this, upgrade it)
  • Wrong hitch angle, which should be slightly nose down.
  • Some (most, if not all) combinations will benefit a lot from an anti-sway device.
4. Speed & External Conditions:
  • Every combination has a speed at which it becomes unstable, sometimes due to the accumulation of small 'problems' which add up as the speed increases
  • Side winds. Moving in next to a truck changes the cross-wind forces, and there is always a suction force that pulls the trailer towards the truck being overtaken, especially if it has high, flat sides, eg a container. The moment you are past the truck, totally different forces act on the tow vehicle and trailer.
  • (Uneven) road surfaces
  • Road camber / super-elevation
  • Road vertical alignment. If there is a cross wind, the forces on the rig changes as you move from a cutting to a fill situation. Combining these with other factors (as above) can cause the rig to become unstable.
Once the rig starts swaying, very few drivers can get it under control. Rather prevent it from happening!

I can assure you that there is no inherent problems with the Pajero as a tow vehicle.

Go through the above to try and find the cause.

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 3:41 pm
by deonengel
:D wow thanks for the replies...

1. i do use a yellow blade stabilizer
2. wind was almost none
3. shocks were replaced about 8000k back..monroe's
4.overtaking speed about 90 - 100km/h
5.tow angle is horizontal
6. when accelerating without towing - feels as if left front lifts - when decelerating it feels as if vehicle is unstable :roll:

i am an old hand at towing - could it be something worn - eg faulty stabilizers

regards - deon

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 8:01 pm
by cloyd
Deon,

Al die aspekte wat die ander lede genoem het, is belangrik. Daar is egter een punt wat ek nog nie gesien het nie: Jou rat kiesing. Wanneer jy iets sleep stel ek voor dat jy 4H kies. Dit maak die wêreld se verskil.

Ek sal selfs so ver gaan om voor te stel dat jy in nat kondisies (pap nat) gaan na 4HDL - dit is net vir ooppad sleep en NIE vir in die stede of wanneer jy skerp moet draai NIE. Baie belangrik: indien jy in 4HDL sleep MOET jy sodra dit droëer word uit 4HDL gaan. Natuurlik ook sodra jy op plekke kom waar daar skerp draaie is bv in berkpasse. Die gewone draaie op die paaie sal nie 'n probleem wees nie - mits dit steeds goed nat is.

Op grondpad sal ek dadelik na 4HDL gaan sodra die pad effens nat is. Die ander "beperkings" bly dieselfde.

Cloyd.

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 8:09 pm
by 4ePikanini
I wouldn't use 4HLc on wet tar. It creates understeer which is dangerous - especially when towing but more importantly it accelerates wear. Tyres in the wet still grip enough to create the windup effect and damage components.

Re: Swaying whilst towing

Posted: Tue Jan 03, 2012 8:34 pm
by deonengel
hi guys, thanks for all this feedback - i am sure we will hit it on the head - cloyd, whilst towing, i tow only in 4th and then also only in 4h - i still wonder if there might not be a worn bush/component or widget :ugeek: somwhere that is causing this problem :|

Re: Swaying whilst towing

Posted: Wed Jan 04, 2012 8:50 pm
by cloyd
Deonengel,

Another thought not mentioned by the other members: Is the caster, camber and toe-in on your rear suspension correct?? If one of the settings is out, it may affect your towing ability. For that matter, are the front settings correct?

A friend of mine used his son-in-laws SWB 3.2 GLS to tow a big caravan from Pretoria to PE and back and he claims he has never towed so easy and according to him at times he was travelling in the illegal speed range!

The important thing about caster camber and toe-in adjustment is to join the technician under the car when he makes adjustments and to ensure that he sets the readings 100% to speck - that is in the middle of the green arch and not somewhere in the green.

Please take note that when I said that at times one can consider towing in 4HDL, I also mentioned that it must be sopping wet. As soon as the water starts to clear, go back to 4H.

Cloyd.