It is dificult finding out the minimum pressures manufacturers allow. Lightweight goods just end up wearing out the centre of the tread. Until the packaging loads changed a couple of years ago the load on a 26 pallet curtainsider weighed about 15cwt and most of that was lightweight pallets. Wear evened out at 125 steer 75 drive and 70/75 (twin/ss) trailer. With axle weights a bit heavier now 3.5/4t the trailers have gone up to 85/90 super single and the drive axle the same. Steer remains as before.
Wear isn’t the only consideration here, too high pressure in drive axle tyres in particular can make an artic skittish, especially and obviously worse in the damp.
My new tractor felt unstable at first, which i put down to new tyres needing to bed in and scrub off the mould releasing agent, however after 3 weeks and no improvement called in at our regular tyre bay, who found the drive axle set in particular over by 10psi, surprising the difference lowering them to our standard spec instantly made.
I have worked for a couple of companies who were ■■■■ about tyre pressures, 130 minimum for super single, 140 if you could find a compressor man enough, 85psi drives and 110 in steers.
It’s amazing that some places do not have the means to check them, never mind inflate them.
1 or 2 psi can make such a difference on a motorcycle from unrideable to fun
Juddian:
Wear isn’t the only consideration here, too high pressure in drive axle tyres in particular can make an artic skittish, especially and obviously worse in the damp.My new tractor felt unstable at first, which i put down to new tyres needing to bed in and scrub off the mould releasing agent, however after 3 weeks and no improvement called in at our regular tyre bay, who found the drive axle set in particular over by 10psi, surprising the difference lowering them to our standard spec instantly made.
Dont forget a cold trye inflated to 125psi,when hot can easily reach in excess on 135psi
Reviving an old discussion.
Could I ask your thoughts and reasoning on what pressures you’d inflate the tyres to on a 44 tonne combination comprising a 6 x 2 tag tractor unit and tri-axle tank trailer. 99% tarmac’d surfaces, majority motorway and the rest rural A and B roads with 50% running empty and 50% running at max weight. The tractor is running 315 80 R 22.5 tyres and the trailer is running 385 65 R 22.5 tyres. Thanks. 
Mick Bracewell:
Reviving an old discussion.Could I ask your thoughts and reasoning on what pressures you’d inflate the tyres to on a 44 tonne combination comprising a 6 x 2 tag tractor unit and tri-axle tank trailer. 99% tarmac’d surfaces, majority motorway and the rest rural A and B roads with 50% running empty and 50% running at max weight. The tractor is running 315 80 R 22.5 tyres and the trailer is running 385 65 R 22.5 tyres. Thanks.
125 on the steer and (presumably) full size tag, try 90 on the drive axle.
Juddian:
Mick Bracewell:
Reviving an old discussion.Could I ask your thoughts and reasoning on what pressures you’d inflate the tyres to on a 44 tonne combination comprising a 6 x 2 tag tractor unit and tri-axle tank trailer. 99% tarmac’d surfaces, majority motorway and the rest rural A and B roads with 50% running empty and 50% running at max weight. The tractor is running 315 80 R 22.5 tyres and the trailer is running 385 65 R 22.5 tyres. Thanks.
125 on the steer and (presumably) full size tag, try 90 on the drive axle.
Agreed and 130 psi on the trailer bogie
Thank both. I shall give those numbers a try. 
Finally got chance to call at our maintenance place to use their inflator today. I was ■■■■■■ off with the truck and trailer feeling like it was dragging its arse all the time so had a strong suspicion the pressures were low. Sure enough, 85 to 100 psi in 4 of the trailer tyres with the other 2 at 120. Unit was 100 and 90 on the steers, 65 to 75 on all 4 drives and 90 psi in both the tag lifts. Happened to catch a mobile HGV tyre fitter working at a neighbouring customer and so asked him what pressures he’d put in them. He reckoned 120 for the trailer and 110 all round for the unit . Decided to run with it and adjust accordingly but then discovered that their compressor wasn’t beefy enough and would only get up to 105-110 psi max. So that’s what I’ve got all round now except the 2 trailer axles which I left on 120. Unit and trailer feels so much better. It actually rolls on its own now in gear instead of slowing down rather rapidly. Unsurprisingly the mpg saw a sizeable uptick too. As far as the ride goes, it’s a bit choppy for my liking when running empty with the tag up, but at 44t it rides really well so I’m happy with that trade off. Definitely reduced the cornering scrub on the tag by giving it a good amount of air.
Will try the steers and trailer with more air once I can find a compressor beefy enough.
Who services and inspects the thing? If they don’t bother with tyre pressures what else don’t they bother checking?
Juddian:
Who services and inspects the thing? If they don’t bother with tyre pressures what else don’t they bother checking?
Inspection doesn’t include tyre pressures. That’s down to the drivers at any transport place which doesn’t have a fleet tyre policy in place.
Mick Bracewell:
Juddian:
Who services and inspects the thing? If they don’t bother with tyre pressures what else don’t they bother checking?Inspection doesn’t include tyre pressures. That’s down to the drivers at any transport place which doesn’t have a fleet tyre policy in place.
A vehicle pmi should include tyre pressures, if they’re following the guide to maintaining roadworthyness. Any transport manager or fleet manager should know what pressures their fleet tyres run on. What make of tyres are you running?
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coiler:
Mick Bracewell:
Juddian:
Who services and inspects the thing? If they don’t bother with tyre pressures what else don’t they bother checking?Inspection doesn’t include tyre pressures. That’s down to the drivers at any transport place which doesn’t have a fleet tyre policy in place.
A vehicle pmi should include tyre pressures, if they’re following the guide to maintaining roadworthyness. Any transport manager or fleet manager should know what pressures their fleet tyres run on. What make of tyres are you running?
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The above policies might be fine and dandy at Eddie Stobart, Wincanton etc, but this is a small family owned food producer where transport is a necessary evil, not their core business. No-one gives a ■■■■ about tyre pressures at such places as they don’t even give a ■■■■ when the trucks have basic maintenance issues and faults until it completely fails and the truck gets stranded somewhere. The mention of a transport manager or fleet manager is funny 
. No idea what makes they are. It’s a different brand on each leg, probably whatever was cheapest 
.
We are slowly bringing the gaffers round to our way of thinking/working and we’re getting some tyre inflator systems wired up to all the trucks’ air supplies which they are happy to pay for. That will have the enough pressure to do 130 psi. It’s just a matter of getting the bits from the local motor factors.