The MOD Father
ball weight has nothing to do with swaying vans,,,
vans have NEVER been designed to be towed,,
they are designed to look pretty and be SOLD.
"How long since you've visited The Good Oil?"
'93 V8 Rossi
'97 to '07. sold.
'01 V8 D2
'06 to 10. written off.
'03 4.6 V8 HSE D2a with Tornado ECM
'10 to '21
'16.5 RRS SDV8
'21 to Infinity and Beyond!
1988 Isuzu Bus. V10 15L NA Diesel
Home is where you park it..
[IMG][/IMG]
ChatterBox
SubscriberSorry Pedro, I disagree.Originally Posted by Pedro_The_Swift
Ball weight = weight distribution = stability/instability. Insufficient weight on the tow = swaying van = potential disaster.
What's your theory ?
Can't argue with this one though.
Deano
The MOD Father
weight distribution??
why should the tow vehicle have to carry any weight??
isnt this why they put wheels under caravans?
I grant you a single axel van is much harder to get right,,
but anything with dual axels should sit on its own/level with no jockey wheel,,
because the makers CANNOT make a saleable/pretty van handle they have moved the axels backwards. All the new vans have the axels waaaaay down the back,,,
and distributed the responsibility back to the car manufacturers.
"How long since you've visited The Good Oil?"
'93 V8 Rossi
'97 to '07. sold.
'01 V8 D2
'06 to 10. written off.
'03 4.6 V8 HSE D2a with Tornado ECM
'10 to '21
'16.5 RRS SDV8
'21 to Infinity and Beyond!
1988 Isuzu Bus. V10 15L NA Diesel
Home is where you park it..
[IMG]
Wizard
i agree. there seems to be a lot of confusion with people betwen a "weight distribution system" and a "sway control device" they are not the same people, so all of you guys that think a weight dist will stop swaying on a badly loaded van...........
a sway control device is a device similiar to a shock absorber which resists swaying movement of a trailer tongue sometimes caused by passing vehicles and wind, and thus controls swaying. not commonly used in australia although probably should be.
a weight distribution system is a hitch system built around a receiver hitch, which includes supplemental equipment such as spring bars that work to distribute trailer tongue loads to the trailer axle(s) and the tow vehicle front axle. Use of weight distribution system enhances handling and braking and increases trailer towing capacity beyond what is recommended when a weight-carrying hitch is used.
both these devices can be used together, but rarely are. seems to be a lot of ppl use the weight dist system to flatten out a badly loaded van and assume it does both jobs.
Master
A van that sits balanced on its own wheels is an accident waiting to happen. How do you think the towing vehicle can have ANY control over the van if the van is free to do its own thing? There MUST be a substantial amount of weight (rule of thumb says 10% of the van's weight) on the towball so that the towing vehicle can exert some control over the van.
Think about it. A van with little or no ball weight can react to every little sideways force (road surface, airstream from passing traffic) and pass that waddle on to the tow vehicle. There was a fatal accident involving a van in SA some years ago. The driver lost control when passing a semi. The coronial enquiry found that the accident was largely due to insufficient ball weight, allowing the van to be affected by the manoeuvre and push the tow vehicle off the road. A photo of the van shows the tandem axles pretty well at the centre of gravity.
Another thing; air bags are NOT a substitute for a WDH. They may raise the rear and level the vehicle, but they do nothing for the weight that is removed from the front wheels by plonking a bloody great weight on the towbar. Granted, with a heavy 4WD like a LR the weight removed may not substantially affect steering or braking, but the principle is valid.
Stephen.
Gday, mate we tow with a WDH and did use it in the LR towbar untill Toombie2 advised it is possible doing this can twist the chassis so we are in the process of changing to a Hayman Reece bar, our van has a ball weight of 210kg and without the WDH the car sits down in the bum, a set of pollie air bags inside the springs would also solve the problem. My advice would be to install a HR bar and use the WDH even if you want to go the extra bit install a set of pollies and the tow vehicle would be spot on and never have to worry.
ChatterBox
SubscriberSorry Pedro, still disagree.
Heres why.
1/. Many years ago towing race car to NSW for hill climb. Monaro towing XU-1 on tandem trailer. On the way up XU-1 pointing forewards on trailer, no problem towing at 120KPH. On the way back had XU-1 backwards on trailer. Got to 100KMH nearly lost the lot with swaying/instability. Only thing that saved us was locking up the electric trailer brakes to pull us up. Not enough weight on draw, turned XU-1 around all fixed.
2/. Two years ago following 16' half cabin on single axle trailer. Boat slipped back on trailer about 1'. Boat pulled up on safety chain OK but trailer now light on tow, started to sway. Hurriedly dropped back and moved behind semi in RH lane. Semi passed boat trailer and 'wind' from semi was enough to send boat trailer into uncontrollable sway. Car and boat jackknifed. Boat and trailer tipped. Car, boat and trailer all wrecked. Fortunately no one hurt. Boat moved ,not enough weight on draw.
3/. A month ago, towing 1500Kg tare 15' single axle van up South road North of Alice Springs. Went to overtake road train, speed 105Kmh van starts to sway badly. Pulled up manually with electric van brakes. Problem here was unknown to me SWMBO had put box of beer, box of Coke and box of tinned food under rear bed in van, about 4' 6" behind the axle. Moved this weight to under seat about 3' in front of axle. Now safe and stable at 120 Kmh. Problem here not enough weight on the draw/too much weight behind axle.
Sorry Pedro you're wrong !
Deano
The MOD Father
not wrong,,
if you are silly enough to load incorrectly then these things happen,,,
if the trailer has a neutral weight fore and aft WHY would it display bad manners???
its physics,,
if the van has no effect on a towing vehicle when stationary,, how does this change in an emergency??
but if the van/whatever has ALREADY compromised the load carrying capacity of the car , and something happens, your safety margin has already been shot to hell,,,
and I can match you trailer for trailer, car for car,
tandem , triple, box,
the simple truth is,
and think about this for a sec,,
if only SOME can do it and not have problems,,
that means the rest are doing something wrong,,
and if one more person mentions a thumb,,,
"How long since you've visited The Good Oil?"
'93 V8 Rossi
'97 to '07. sold.
'01 V8 D2
'06 to 10. written off.
'03 4.6 V8 HSE D2a with Tornado ECM
'10 to '21
'16.5 RRS SDV8
'21 to Infinity and Beyond!
1988 Isuzu Bus. V10 15L NA Diesel
Home is where you park it..
[IMG]
Wizard
sorry to say but i see two common denominators in these 3 scenarios,
1: driver
2: speed
common sense to me would say that if i am going to overtake a roadtrain at 105klm/h towing a 15' windsail on the back, there is a pretty large chance its gunna get hit with the air wave off the road train, and guess what, possibly make it sway,
xu1 facing backwards is an aerodynamic brick, forwards not too bad
boat held on a trailer only by a chain after dropping back a foot is probly going to sway, guess thats just pure physics
ChatterBox
SubscriberPedro, some of your points I do agree with But not perhaps your logic on others.
No problems here, I guess it's about how you define incorrectly. In the three examples I gave all were instability problems solved by increasing weight on the tow. Therefore I conclude the problem was caused by insufficient weight on the tow initially.
Perhaps the difference is that when you have more weight behind the axle, sideways forces acting on this weight tend to twist the trailer around its pivot point (axle) puting force on the tow bar in the opposite direction. A bit like when a live axle goes down the other end goes up. When there is more weight in front of the axle this isn't an issue as this weight tends to dampen this effect. Each Kg of weight more than a neutral load in front of the axle tends to a/. decrease that force by 1 Kg and provide a dampening of 1 Kg. A double benefit if you like. I don't really know the explanation I'm not a rocket scientist. But I do know this, low weight on draw = instability = disaster.
You're right It's physics. I'm not a physicist so I can't explain it. I can see the effect (instability) and I can resolve it by altering the load balance in the trailer. So to me the cause and effect are pretty clear.
When their moving, the forces on both the towing and towed vehicle are different and constantly changing. No comparison to being stationary.
No argument here.
Pointless exercise.
Or perhaps they are doing it (towing) right and just don't recognise it !
Sorry Pedro I still reckon your'e wrong.
Just as well wer'e not doing this over a beer, we'd end up not knowing what the hell we were arguing about.
Deano
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