N.O.S.

And it can carry a fair bit more too, Loggy :-)

I didn't stay long abn - the beer was FLAT and the barman was dressed in rubber. Not my scene.

Oh dear, I can't cope with Scalar Quantities. Mike - how about we have a beer (Bernard's getting a round in at the clubhouse right now) and call it a draw? :-D

Now that is real friendship. Thanks for posting.

Not so fast........:nono: Yes the circumference of the tyre is to all intents and purposes uncompressible. Those bl%%dy army 12x20 cross ply sidewalls are not much better. But a radial tyre sidewall is immensly flexible by comparison, and can tolerate a fair degree of torsional (rotational, radial) wind-up, as well as axial flexing (sidewalls bulging under load). Try another one of Professor Crump's illustrations (this is highly simplified but serves the purpose here): Both tyres here have the same cirumference. The one below demonstrates that when compressed under load the effective rolling radius R2 is reduced. But note also that the equivalent rolling radius at the top of the tyre R3 (not you Richard) becomes greater. This is because the tread cannot be compressed, so the sidewalls flex to allow it to move away from the rim to retain its 'length'. At the top the velocity of the tread relative to the hub V2 must therefore be greater than at the bottom V1. So the tyre tread effectively plays "catch-up" as it rolls around to the road once more, where it slows down to pass between the rim and the road. So the velocity V of each point of the outside of the tyre is constantly varying - but the average velocity must be equal to that of the tyre shown at the top unless the tyre spins on the rim. If you don't believe this, try sticking 8 tonnes in the 4t capacity bucket of a 4wd artic loader with soft radial tyres (which were admittedly 'a bit slack' :embarrassed: ) and see how the rear tyres scrabble around trying to push the machine faster than the fronts (which were doing the gripping) will allow. Come to think of it the fronts looked just like Prof. Crump's lower tyre :wow: In fact large earthmover tyres are a good example of how different tyre pressures - for front / rear on multi axle drive machines with differing axle loadings and no centre differential - are critical to achieving the same rolling radius, and resulting smooth non-kangaroo ride. When matching truck tyres, the cirumference is always going to be proportional to unloaded diameter. Maybe some people measure the circumference (3.142 x dia.) as it gives a much more accurate way of matching tyres of the same diameter (and hence circumference) than by trying to accurately measure the diameter. You have to assume that two truck tyres of similar circumference / diameter and pressure will have the same rolling radius. You can't play around with truck tyre pressures to jiggle rolling radius, because truck tyres require a specific pressure to carry the load safely.

Take your tank track thing. The only dimension that affects how far the tank travels with a track of variable length is the radius of the drive sprocket, which equates to rolling radius of a tyre. The drawing below shows a short track, a long track, and a track held in the shape of a radial tyre with one mother of a sidewall bulge :-D They all travel at the same speed ('R'is the same). Hey, here comes uncle Bob again!

Given the potential trailer problems, would it be easier to get a s/h 7.5t beavertail truck? Would carry 4t ok.

As Bernard says the difference may not be much at all. And even if it is, you could always let air out of the radial tyre (if you ever have to use it) until the hub (or edge of wheel rim) is exactly the same height off the road as the other one on the same walking beam (subject to driving 'carefully' of course :cool2:). Would save any undue stress on the gearing too. And black marks on the road from the crossply tyre on the same walking beam :-D

Were you getting directed to a site called Pathfinder Community Services?

Tres bon - le "proper job!"

The front shackle of the front spring (to the right of this picture) is attached to the base of a 5" dia. piston, on the top of which sits air compessed to 88 psi in the domed can seen from the front, so it is effectively an extra 'cushioning spring'.

These are simply AMAZING photos - thanks for sharing!

'Guss' air springs. Does the same as a modern air bag.

I'm certain this is a post war trailer - looks like a U.S. design too. Somewhere I have a photo of the twin axle version which was on a farm locally as a sprayer bowser - like the single axle tanker above it had a lower profile than the ww2 ones. I'll keep looking.

You are right again. And the narrower cab of the Sterling gives it a more 'balanced' look. Classic Americana no less. Definitely drool :-D

:nono: A 4BT would, but it just wouldn't sound right......

Wonder if he took the chance to have a grease-up? :cool2:

Sorry, but what's to discuss? If it purports to REPRESENT the Forum, surely it should be ON the forum, or at least made available to forum members. I think the majority of us are grown-up enough not to criticise our Latin Teacher's lecture notes :-D If there are valid concerns about putting it on, perhaps it could be made available to members by PM upon request, with a committment from those folk not to copy it elsewhere? I'd certainly be happy with that arrangement.

Indeed Andy. There was a big puddle of drool at the spot from which I took the photo....... :blush:

Agreed Michele, I'd forgotten about the taller Sterling. Even with the same DT 969 style mudguards it is a very elegant 'high stepping' truck. I took this photo at Overloon - I think this is the DDS235?.

Here's the link to the LCT "Landfall" website: http://evans-experientialism.freewebspace.com/landfallcontentspage.htm

I've always thought the Sterling looked out of proportion - almost ugly even - for a heavy truck. The cab and bonnet sit far too low on the chassis, making the equipment on the back look like an outsize load. Like a heavy truck version of a Californian street rod. Compare the Sterling profile to that of the Federal. But better for dodging bullets no doubt!! They were only used by the U.S. Navy I believe.

And this is what they sound like - more like a petrol than many big diesels:

Interesting - could you enlighten us a bit more on the American RV situation please?

The 5.9 litre 6BTA should give out 200 hp and 500 ft.lbs torque at something between 2,440 and 2,600rpm (depends on spec). Compare to the Continental 8 litre petrol - 2,400 rpm / 145 hp / 372 ft.lbs. Even the 130 hp non-turbo 6B should be able to match the Continental's peformance. Marine spec. engines can exceed 300 hp!