Does length relate to age?

Single axle Carapark van. Don't know how old - I bought it S/H in 1964.

Towball to axle 2750

Overall length, back of van to towball 4500

Towball to front of van 780

Tandem Regal. Don't know the age, I bought it S/H in 1993.

Towball to mid point of axles 4050

Overall length Back of van to towball 7000

Towball to front of van ~1000 (depends which bit of front you measure!)

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Originally Posted by rick130

FWIW Pedro there didn't seem to be any hard and fast rules way back in the day, I remember dad talking about this when he was modifying our old Newlands van for off road use back in the mid 70's. (Flipped drop axle, reinforced draw bar, shock absorbers, generator, etc)

He always reckoned most vans and trailers for that matter had too short a draw bar length, that a longer distance from the tow ball to the axle towed better (more stability) and most importantly backed more easily as it slowed the reaction time down.

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In addition of lengthening on the existing van it will lower the tow ball weight......

However I nearly all cases when length is added normally a big storage box follows and tow weight goes through the roof.

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Originally Posted by JDNSW

Single axle Carapark van. Don't know how old - I bought it S/H in 1964.

Towball to front of van 780

Tandem Regal. Don't know the age, I bought it S/H in 1993.

Towball to front of van ~1000 (depends which bit of front you measure!)

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Those towball to front of van measurements are incredibly short!

I suspect that they were both designed long before trayback utes were at all common, and they were designed to be towed by cars, with the towbar well behind the rear bumper, and furthermore, narrower than the typical trayback that most vans must be designed to be used with. The Carapark has nothing on the towbar, the Regal has a single gas bottle.

I have two "box" trailers -
#1: Draw bar length to axle, 3.0, to body, 1.9. This one only has a box on the drawbar.
#2: Draw bar length to axle, 2.65, to body, 0.55. This one has spare wheels (horizontally) on the draw bar.

As already pointed out, a longer draw bar gives less sway; lower ball weight; easier reversing.

I don't think this is related to age - I can think of examples of 50s design that had long draw bars, but there were also examples of stupidly short ones from that era too.

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Originally Posted by Slunnie

Those towball to front of van measurements are incredibly short!

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Yeah - they used to make them very short. The measurement I gave of 1260mm for my old Viscount is from the hitch to the front of the chassis but the vans front overhangs that by just over 300mm so hitch to front of van is around 900mm. JUST enough not to dint the van if you jackknife it when reversing. [emoji6]

In 1967 I lent my Carapark and my 2a trayback to a close friend for his honeymoon. ......... It still has the puncture in the front skin where the corner of the tray hit it!

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Originally Posted by jh972

jh972 I have two "box" trailers -
As already pointed out, a longer draw bar gives less sway; lower ball weight; easier reversing.

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Hi, that is correct, but it should be noted that when you decrease the ball weight you increase the GTM (or load on the axles) if you maintain the same ATM and if the ball weight is less than the rule of thumb 9-10% of ATM (ATM is the GTM + Ball Weight added together) then you may produce a more UNstable tow since the van may porpoise and try to lift the back of the tug vehicle. Just saying :)

On that note, a correctly loaded van (that is the payload inside the van distributed between the tow ball and the axles, so centre of mass is just forward of the axle centre) will have a far greater affect on the towing stability of the rig (ie: tug and van together) This is easier said than done, but you should try anyway, it all helps.

Further, many vans are likely to be overloaded, creating an even more dangerous scenario compared to the poorly loaded van. The weigh bridge is your friend. I also weighed every bit of kit I carry on scales and tabulated the data and I have tow ball scales too.

Another thing often overlooked is the length of the tow ball tongue on the tug. This should be as short as practical to put the tow ball as close to the rear axle of the tug as you can. The best scenario here is a fifth wheeler where it is right over the axle. A shorter tongue will give the van less leverage to move the tug vehicle around. I am afraid those long tray back vehicles aren't ideal for heavy towing.

OK, off the soapbox and onto my measurements.
For the record, I, along with a certified automotive engineer, have redesigned the dual axle leaf suspension using adjustable air to increase the van's ATM, and added 4 shocks to reduce sway. The work was completed by a certified heavy vehicle engineer firm here in Townsville. It tows really well, very very stable.

My van is a 2006 Galaxy Starion G21 21.6ft, ATM 3500Kg, GTM 3150Kg, Tow Ball 350Kg, Tare 2280Kg, Max Payload 870Kg. I usually carry a payload of 450Kg ish and a tow ball weight of 310Kg
Metres --- Dimension ----------- Description
8.85 ------ Length Over All ----- Ball to back of spare tyre
7.30 ------ Length of Body ----- Curve of boot to flat of tail end
0.30 ------ Rear Overhang ------ Bumper & Spare Tyre
1.25 ------ A Frame ------------ Ball to curve of boot
5.37 ------ Axle Centre --------- Ball to mid point between axles

Hope that is helpful, Cheers n beers, Mick [thumbsupbig]

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Originally Posted by JDNSW

In 1967 I lent my Carapark and my 2a trayback to a close friend for his honeymoon. ......... It still has the puncture in the front skin where the corner of the tray hit it!

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It was probably the bride when she saw the honeymoon arrangements