Spread axle trailers

As a kid in the 70s I remember there being a lot of bogie trailers with a gap between the axles. Like a tri axle with the middle axle removed. Does anyone know the history of these and their advantages over conventional axle spacing?

Yes, remember them all right.

The reason for the gap was to allow a bit more "puddin" to be put on the rear end, worked exceptionally well in a straight line, but do not attempt to turn a corner to quick on a hot day fully loaded. It just rolled the hot bitumen out of the way, either front axle or rear axle, depended on which axle that didn't have all the weight on it, that axle just scuffed and dragged.
Yep, the tyres copped a 'pizzlin' too, scrubbed 'em out real quick.
Don't try and reverse an empty one down a driveway if the road had a hump in it and a dip where the gutter should be, it started of doing the right thing and then just took off as an axle got out into the fresh air, boy, was it a bit of trial and error with them things.

Now this is only from what the grey cells are tell me, 'cause it's been quite a while since I had one on behind. Think you used to be able to get 15 or 16 ton on a closed bogie, then along comes the open bogie and this allowed the weight out to 18.5 tons, Swishy will say if that's right or wrong.

So NO advantage over a bogie or a tri axle at all, that's why they went the way of the dinosaurs.

regards greenie [smiley=vrolijk_1.gif]

They have changed the regulations and out lawed them as well, though you can still register them on historic rego, on a bogie centre to centre on the axle's can't be any more than 2.0m now.

Up until at least the late 70's Victoria didn't recognise triaxles and a normal bogie was limited to 13.3 tonne.

But by using the "Bridge formula" a spread bogie at about 2.4 metres was allowed about 15 tonne.

Bridge formula was literally aimed to protect bridges by limiting the concentration of loading so the greater the distance between axles the greater the gross load. However the maximum individual axle load still couldn't be exceeded hence the long equaliser beams used to achieve some load sharing.

Bridge formula was applied across both axles groups and the entire rig which lead to some creativity.

Camerons experimented with a rigid plus dog configuration with a spread bogie drive on a Kenworth using a re-arranged KW torsion bar suspension.

From T&BT November 1971

And a correction - not a dog trailer but a single axle semi with a single axle dolly.

Jimbo
GuddayM8
Sorry
but U loosen me there

TH@ Pic
Is Camerons Spread bogie drive on torsion bar suspension with a dog or pup trailer
rumored to go straight ahead in the wet

ButEyeDoSt&2BCorrected!
Cya
[ch9787]

Swishy,
GuddayM8,

We're in agreement on the bogie drive on crowbars on the rigid.

As far as the back bit, I'm only going by the article in T&TB that reckons it's a semi with a dolly. Apparently inspired by the short doubles used in the US.

Tried to blow up the photo and see if there's a quick release turntable but inconclusive.

Just looking at the rig I reckon they would have needed to issue the drivers uniforms with a couple of extra pairs of jocks!

Jimbo
Sme again
OK now I get u're drift
isn't a dog trailer just a semi with a set of wheels under the front towed by a draw bar
But now eye C
for local deliveries U'd need to run the Dog trailer as a semi under a primover as they'd never back th@ thing on the spread bogie drive KW as the draw bar iz F far tooo short
Gilbertsons from Port Melbourne also had a Spread bogie drive KW as a tray me thinks towing a dog tray

Cya
[ch9787]

Swishy,
We're on the same page now mate. We're either both right or both wrong.

Was Gilbertsons another one or the Camerons one passed on and re-bodied?

Sorry to be correcting you Swishy, but a long time ago I used to subbie for Carpentaria Transport, who where basically NQX and QRX. They had a few Dog trailers with real short drawbars, and the trucks had a lot more overhang than the Cameron's truck, no dolly locks, and the drivers used to back them into docks. I am still in awe of thier ability, I was quite cool doing it in a semi, but the Dog trailer with no dolly lock is no easy thing.