Drawbar length

[sutcac]

Is there an optimium drawbar length?
Just towed Fugly Foldout down to the Tweed get together and she got a bit untidy at times!( swaying) There was a bit of a cross wind about , but nothing too severe.(15/20 kph perhaps)
I know Fugly isn't too aerodin.........aerodinem...... she pushes a fair bit of wind hey ?
Was a bit better on the return trip today with 38 psi in the radial tyres instead of 25 psi............but still swayed a little on a couple of occasions at around 90 kph (would like to be able to tow at around 100kph on the freeway in ideal conditions)........or am I expecting too much?
The suspension on the EH is probably the original and she drives pretty "loose". Am considering spending the money and replacing front coils, 4 x new quality shockies, add one new leaf spring to restore original ride height and stiffness.Iguess this would help the cause a bit !
Am going to replace the 40 yr old tow hitch with a new one for the East Coast S T....... just for safety.
Question;.....should I consider extending the draw bar while I 'm at it ?

Fugly has solid dropped axle in good nick.Weighs in at 750 kg laden. No Brakes. 65 kg weight on the ball. Distance from axle to tow hitch is 2420mm.
Any advice greatly appreciated .
Thanks , Sutcac.

PS .....think I might have been "spoilt" towing the Sunny too much lately. Nothin' tows as good as a Sunliner !!!!!!!!!!!!! ;D ;D ;D ;D ;D ;D

[chippydave01]

Hi Sutcac,you have definately been spoilt towing a sunliner.I towed one for 90 mins and couldnt beleive I was actually towing a van,I had to keep looking to see if it was still there and keeping checking my speedo to stay within legal limits.But my tandem also tows awesome. Cheers Dave

[jailbarjuice guest]

Hi sutcac,

I was told years ago that radials on a van arent as good for towing as conventional tyres. the Millard I had at the time had conventionals, & it towed well.

So I,ve always used conventionals, but thats only on the 3 vans I've used in the last 10 years.

Groovin has quite a short towbar, & rides high. It has conventionals. It towed very well at any speed, & only moved around in a truck's draught as they passed

My Sunliner runs a cheap 13" Indian made convential, & towed like a dream, probably better than anything I've towed. Boots drove some of the way home on Sunday. she had never towed a trailer or van before, & didnt notice any difference between having the van behind or not.

I really have nothing but hearsay to confirm the facts about radials, but I definitely wont be using them on any van I have.


I personally think I will turn out to be probably the way the van is loaded.

My mother used to pack our ply van when I was a kid. we'd always get a couple of miles from home, & as Dad picked up a bit of speed the van would dance around & sway. Dad always then removed everything heavy from above knee height, & packed it on the floor. That was always enough to stop the van moving the back of the car around.

I dont know how you pack your van, but maybe that could be a factor?

What ever it ends up being, I'd play around with it before changing anything structurally.

maybe you can borrow a set of conventionals.

One last thing, didnt you swap van wheels with OB at Tweed?

If it behaved itself on the way down, but not after you swapped wheels, you've found the problem.

All the best with sorting it out.

Jailbarjuice

[humpty2]

As you said Clyde "it's all about aerodynamics!".....plus I run about 40 PSI in my van tyres., which are radials.....got air shocks on the rear and new shockies up front on the EH.......oh and 35 PSI all round!
Tow ball weight is pretty close...10% is the general figure.
I towed "Humpty" in a roaring Westerly and rain to Tamworth in July....as we started out I said to my self "self, this is gunna be a bumpy ride", but I travelled easily at 90 kph....due to the beaut aerodynamics of the Sunliner.
Your solution...........line up for when I finish the "Sunliner" under restoration here ;D ;D ;D ;D.

I dont think the draw bar will really be the problem......ideally the distance of the towed wheels should be the same as the steered wheels from the rear axle.
Regards Peter

[Deleted]

Hey Collide

I remember getting repremanded off Col on last years spring tour for running too much pressure in the tyres on matilda. I had around 36 psi in them when i shredded one of them. we ended up fitting the spare and dropping them to 25psi or there abouts. What you have to consider is they arent transmitting power to the ground and although caravans look large and bulky they arent overly heavy.
Probably around 300kg on each wheel.
If you blow things up rock hard you are probably getting the same effect that you get when you blow up a basketball rock hard and bounce it.

I am with dennis on this one. In My very first post ( the first time around) i complained about the old van "Just Croozn" swaying around on the way home from the paddock we retrieved it from.
It had 13" Holden wheels and i towed it with a turbo diesel landcriuser with 15" wheels. The van was nose up onto the towball which shifted a fair bit of weight back over the van axle which in turn caused it to sway at anything over 80Ks.

Mark T replied with " pack everything low and forward in the van. " he mentioned " at least 3 cartons of my favourite brew".
I ended up making up a gooseneck which lowered the towball to near level. The van towed perfect after that.

You mentioned 65KG towball weight . That to me suggests that you already have a fair amount of weight forward in the van.? Might have to stiffen the bum of the EH up a bit.?? How does it sit with the van on it?? If the nose of the car is higher than the bum then your castor angle on the front will also change giving you lighter steering which may be causing things to wander around a bit??

All things to think about i suppose.
Reddo

[Roehm3108]

Hi Clyde
Guess you made it home OK.
I have a different thought to the other guys. I recently gave this advice to my son-in-law who has just bought a Sunwagon Camper. It weighs about 900kg loaded.
I maintain you get better stability simply by adding a pair of stabiliser bars if you don't already have them. This also adds to your overall safety if you have to brake suddenly. Have always used them on my vans except the Propert, which really is a trailer. I even used them on my first VV, a 10 1/2 ft Franklin. I reckon that the length of the drawbar will only dictate where the van will hit your car if you happen to jack-knife it
Worth a try, as they are much cheaper than fiddling around with changing the length of drawbars.
Don't deny that tyre pressure has an effect too, but by how much I would not be sure.
Ray

[tinnie]

Gday,

I agree with Ray that the drawbar length means bugga-awl. My Franklin has a really short draw bar and it tows fine (only sways in strong side wind). I have towed it with and with-out level rides, and the level rides only seem to impact on the sag in butt of car (not that there is much) and moreso seem to stop the van bouncing around over bumps as bad.
TYRE PRESSURE:
I am baffled by this. So called experts (i.e. new van dealers) have said to run 40 psi on tandem vans and 50psi on single axle vans. I run about 30psi and I wonder if running higher pressure will make the van bounce more??Or less?? It only weighs around 650kg.
As for running 50PSI in 45 year old 13 inch wheels Asking for trouble I reckon so I aint going there.
My local Tyre dealer (who is a smart operator) told me to run 35PSI in the car tyres and go up to 40psi in rears if towing heavy loads.

What do others reckon about appropriate tyre pressure?? Particularly in older single axle vans, such as most of us have.

Cheers,
Gristy

[Roehm3108]

Done some more ruminating last night about this vexing question. I'm no eggspurt mind you, but 65kg ball-weight seems a bit low - considering the general rule of thumb being that the ball weight should be 10% of the overall weight. Which means that your van may be too well balanced. So you might be better off getting a bit more weight towards the front of the axle to give you more stability. That would make the need for stabiliser bars even more important.
Having the stabilser bars on will, as Gristy mentioned, give a much better "feel" of driving as the front wheels are pushed down and grip the road much better. It could be that because of the front-end lightness, it's the car that starts the wobblies rather than the van itself, as you tend to over-correct for the car drift.
Another thing to consider if things don't improve is putting an air-foil on top of the car, if you have roof-racks for it. that certainly will assist the wind drag because of the square-ness of your rig.
I have light truck tyres on my No1 Propert and the Superb, which I reckon are the best tyres to get for any van. And the Superb is very boxy too. May not look as smart as radials, but do what they were designed to do - carry the load!
I would start with the stabilisers and see how they perform before changing drawbars and tyres. They get you out of that sway much quicker and settle the whole unit down much more safely.
Ray

[humpty2]

Oh I forgot to mention that I also use a single stabliser on each side.....that's the one with the D type mounting point.

[jrod]

Hi Sutcat,

First off im impressed that the EH could pull the van through a wind at 100kph!!

I reckon the guys have covered just about most of it. I replaced the susp in my HT in between its first and second tow. It drove a hell of a lot better, but to be honest the van towed the same. It obviously just felt better when the car was tighter.

I agree with running slightly higher pressure in the rears of your car. I always tend to run higher pressure in the van too, but think 35psi would be plenty now having read the comments here. You also need to check that the van when coupled on to the back of the car sits flat and isn't a little high in the front. If it is it may be worthwhile getting the coupling re-positioned. Pack the van wisely, and also look into JBJ's suggestion of conventional tyres. My Dad still vowes that his van towed better on crossply's than radials due to the flex in the sidewall. I run the Camec equalizer bars which seem to help the back of the old girl from sitting right down, and are supposed to assist swaying.

Hope you find a cure!

J-Rod

[JBJ]

hi All,


I never use sway bars.

I had a Millard Mini that had them fitted. First time I towed it I left them off. It towed good, including a couple of relatively fast squirts on a long flat, slightly bumpy, straight stretch of back road

So I went home, put the bars on, & drove the same road the same way.

I couldn't detect any difference at all. Maybe I'm lucky I,ve got a couple of fairly heavy towcars, although the EH towed the Purdon on last years spring tour without sway bars, & had absolutely no movement at any time.

I still believe its got a lot to do with running the flat profile of tread that a convential tyre has.

But whatever, no one can convince me that sway bars do anything to help on the vehicles & vans I've used, & am using.

To each his own.

Jailbarjuice

[sutcac]

Wow! thanks everyone for responding to my post. Everything that each respondent said , made sense to me.
Jb.... Ian and I did swap wheels and tyres at the Tweed........but it was 13" holden rims and radials for 13" holden rims and radials.........so that wasn't the problem.....towed much the same each way.
Humpty......the wheelbase of the car is only about 200 mm less than the distance from the tow ball to the trailer axle.
Reddo....yep, the bum of the EH is abit down with the front end up slightly.
Ray .....ran load levellers on the Sunny, so the EH is set up for them ..........will throw a set on if what I"ve tried doesn't work.
J Rod.... I tend to agree that conventional cross plys may tow better because of the lesser sidewall movement....ie a stiffer sidewall section :

Had alook in the van.........,I had afair bit of stuff stored up high at the front so decided to relocate it down low ,into a stowage box on the drawbar.

[sutcac]

The fire extinguisher and snake bite kit are up high too.......but they"re stayin put!!!! ;D ;D ;D ;D ;D



Dug up some old form ply and knocked up a rough storage box......1500 x320 x 320



Mounted the box on the drawbar.......it holds poles , pegs , ropes , hose , electric leads , tarps ,hammers, foldup table and chairs , jacking plates etc etc



The setup has added 10 kg to the drawbar weight ........ now 75 kg.......exactly 10% of the vans weight. The EH goes into Pedders on Monday for coils, shockies and extra leaf springs to stiffen the rear end up a bit.



Will let you know how she tows next time out. ;D ;D ;D ;D

Woops... . next time out will be Coledale and the East Coast Spring Tour.....will tell ya"s how she towed when I see ya's all in a coupla weeks !!! ;D ;D ;D ;D ;D

Thanks , Sutcac

[humpty2]

Just watch the box when you reverse and turn!!!
The reason I run 40psi in the van is because they are radials, I reckon you could get away with about 30/35psi on conventionals.

Humpty

[Roehm3108]

Hi Sutcac
When you DO find the optimum towing method, perhaps you could share it on this site as well, for the benefit of those who can't make it to Coledale this year
This sort of info is very important to safer towing of our precious vans and any feedback is helpful. I've not had any trouble, no matter which rig I take, but then I do use a modern car which probably makes a difference too.
Cheers
Ray

[Deleted]

Hey Collide

Something that hasnt been mentioned yet is in amongst all this here debate is ..... the spring rating on the van??
How many leaves is on either side. Something the size of your concertina box may need at least 5 leaves either side to keep it on the straight and narrow??

Again this was talked about in my very first post to the forum back in August ... or was it .october 2004.
At the time i was convinced i should bolt a pair of double acting shockys under the van to help avoid spring rebound.

The problem of sway could come about because your springs are too soft.
Once the thing starts swaying the effect is magnified because the load is being transferred from one side to the other. Each time the opposing spring is loaded to the max it throws the weight to the other side. starts out as a minor effect then gradually gets worse until you either accelerate or go around a corner?

Oh yeah.....I read somewhere in a caravanning magazine that the "sway bars" are not fitted so much for sway but more so to transfer the weight from the sagging bum of the towcar to the front of the car... "Load levelling". But They put a hell of a strain on the gooseneck/ coupling and towbar mounts . I use to use them but have given up using them over the past twelve months and havent had a drama. You can hear them grinding away as you drive out of a driveway at a servo and onto the road. The bars ar fighting against the van and the car wanting to" Vee "at the coupling...... as i said... a hell of a strain on everything. especially if you are running a "4 Bar " set up.

Just another twisted thought from "chopper" the lop eared varmint in the "shed of invention".

[Roehm3108]

Without wanting to extend this debate further, I do think that the following site is worthwhile reading for us all:

www.towingguide.com.au/towtrailer.html

Ray

[jrod]

Good point on the stress placed on the towbar Reddo.

I run the 4 bar setup and have been concerend with the stress it places on the towbar. I noticed the paint on the towbar slightly cracking in one place, not a good sign if it is attributed to the bars and not my shotty painting attempt.

I use mine only to level the car, whether they assist swaying is debatable, i certainly haven't noticed a difference. I may try and lose them on the tour, would hate for the towbar to fall off from the leverage place on the back of the old Nasco setup.

On the other hand, i doubt anyone on the forum runs a Hayam Reece Full Hitch set up, but they are engineered for the leverage the bars apply to both gooseneck and hitch as opposed to the standard fixed towbar setup.

Cheers J-Rod

[Deleted]

Hi J-Rod

The towbar fixing points on an old holden are only about75 to 100mm apart on either side. they bolt through lightweight box section with no crush tubes.

Now i aint no engineer, but when you consider the cantilever effect of a caravan rocking up and down on your towball at the end of the tongue( gooseneck) it isnt hard to imagine the stress thats being taken on old 1/2" UNF bolts in 50 year old steel. .
I would feel happier towing with a 2 or 4 bar set up if the towbar had "Outriggers " that extended back under the car and bolted on somewhere near the dogleg in the chassis/ subframe.
Sorta like a chassis strengthing kit that hadfield sells for the other end of the car.

At least the load would be spread over a greater distance and the towbar would be less prone to move / pivot backwards and fowards as the load comes on and off the towball.


See i do spend some time in the shed of invention thinking ,,, not just chopping off ears and blowing myself up ;D

I am bound to get shot down by the "slide rule snipers". On this theory......I dont care i enjoy debate .

Reddo

[Roehm3108]

Reddo, what you say is what worried me about the EJ. Was never happy about the way the towbar fitted to the body and couldn't imagine it being safe for amything around the magic ton weight, which is easily achieved with even a 10-12ft van. For that reason, I only ever intended to tow the Propert with it, which, to my mind would have been maximum safe weight.
I remember years ago I had a Datsun 180B, with which I towed a Millard Micro (about 10ft 6inches). The towbar installer fitted reinforcing bars in the boot and bolted the tow-bar to them, rather than merely relying on the chassis for strength. That worked very well, and I never had a problem. Is this something that you could muse over in that shed of inventions??? Trying to do something with the levelling bars might get too complicated engineering-wise, and create more problems than fixing them. Just don't stick your head where it shouldn't be again - you may not be so lucky next time ;D ;D ;D
Ray

[jrod]

Hi Reddo,

Glad to see that the chopper incindent was only cosmetic! ;D

Thanks for the info, i recall when i had the rear leaf springs reset the guy told me that he wouldn't be too keen towing a car trailer with a car on it with the way the nasco bar is fixed.

Will try and get away without the bars, i just cant recall how far the HT sits down with the van on the back..

Cheers J-Rod

[raym]

Hi all,
If you do not want to run convential tyres and radial tyres could be a problem, try light truck tyres they are radials but are 6 or 8 ply in lieu of 2 ply car tyres. I have had good results with these on vans and trailers and they have made a difference.
Another thing to check is that the axle on the van is 6 inches (150mm) back off centre of the body of the van. This is a must.
raym

[minicamper]

If i can add my two bits worth?

I don't know about trailer typre pressures, but I might add my experiences with car tyres.

#1- I wouldn't worry about higher pressures on older rims as long as they are in good nick. My fellow model T'ers and I run anything from 30-40psi on a range of rims from 80yrs old and more (granted in tubes) some of these are split rims, some metal wire rims some wooden fellow rims. In the trucks we run up to 50psi

#2 many of you mention "conventionals" I assume you mean crossplies? I have a couple of older cars running on crossplies. I've found that the recommended vehicle pressures are a touch too low (around 25-28psi) and make the rear end wobble around ( ) i know the vans don't have the whole providing traction/weight thing going, but i find around 30 psi seems good.

#3 I vote loading technique. I can clearly remember as a kid the effort we put into packing our very first van (ok so it was a brand spanker Jayco in 1980) and our troubles always seemed to be around poor loading technique.

That's what I think, but who says I know anything!

[Roehm3108]

So, Clyde, after all this advice you got, what DID you end up doing to Fugly, and how did it work on the trip??
Ray

[sutcac]

Hi Ray. Shifted a fair bit of weight from up high in the van to the new storage box on the drawbar........new( Viagra brand) front/rear springs/shockies on the Prem.....stiffened things up considerably! .............this raised the whole car about 50/60mm, so had to rebend the towbar tongue down the same amount to get the van riding level again.........ran 38 psi in the van's 13" radials and and 36ish allround on the Prem................towed much better all round ...........although Kaybee and Reddo might disagree after following me for awhile at different times.........Col commented that the little Fugly Foldout appeared to be "stepping out " considerably at times......and looked a bit untidy .........but that was over some undulating, wavy surfaced type roads if I remember correctly.............. .
I do tend to tow just a bit too quick at times, and in hindsight, if I was to back off to around 90kph, instead ofthe 95 to 100 I quite often try to run at, then things might be just a little more stable all round.
Your aerofoil idea on racks ontop of the car would work too ,especially set on the rear section of a station wagon type vehicle, closer to the van itself.
Am going to have a look around some truck wreckers for a fibreglass air streamliner thingo that they run on the high(above cab) part of the pantec. ....cut n shut it to fit on the top half of the front of the van.
Saw a doco years ago ,where a transport company fitted these to their fleet an cut their fuel bill by 25-30%1!!!!!!!!!!!!!!!!!!!!!
Am tempted to fit some light truck 6/8 plys , as I agree that a stiffer sidewall( how about that, must be Viagra brand tyres available too) would help the cause also.
Thanks to all for their input to this thread. It's all helped me to make decisions, that have resulted in the overall improvement in the towing capabilities of the little Fugly

Or was it the signage on the back of the van that helped keep "abreast" of the situation? ;D ;D ;D ;D ;D

Sutcac