Tire pressure towing

[coopers1969]

Hey all
i am after some advise I pull a block of flats and all up I am just over 6.2 tons. I have put new Bridgestone 255/55/19 dueled AT 002 on they came with 42 psi and when I stopped I check the pressure it was over 51psi😱 so I wen to 44 psi and again tire pressure at 53psi 😱 and I am now at 46 psi and I have seen pressure upto 54 psi how high do I need to go to get the 4psi rule to apply I am thinking up to 50 psi but man this seems high. Yes I am heavy I have a wheel carrier long range tank and 320kg on the ball. So maybe 50 psi is right. Thoughts from anyone towing ps only on the black stuff on the way home.

[rocket rod]

I tow a van lighter than yours but I've tried different pressures and they all end up 4-6PSI higher than starting pressure so I can't tell by the rule which one is right either but I can say that without van I have 40PSI in the back and with, I have 44. I have 265/60/18 AT tyres. The temperature rises are all about the same too BTW

[shanegtr]

If you know your axle weights then I've found you can calculate a reasonable starting pressure to tweak from. Find your tyre max PSI and weight on the tyre sidewall (single tyre figures not dual). Calculation as follows: (Max PSI / Max weight) x Axle weight /2
With my D3 tyres are max 80psi @ 1450kgs. Axle weight 1766
(80 / 1450) x 1766 / 2 = 48.7Psi

Give it a try and see where your pressures end up

[TonyC]

I've never been able to get the 4psi rule to work for the rears tyres on my Defender.
Completely different tyres, 255/85R16 LT, but even at max cold pressure, with less than half their rated load, I still get 8 plus PSI rise.
For the front the 4 PSI rule seems to work.

Tony

[Pedro_The_Swift]

6.1T and 50lbs on the rears 40 on the front. 255 x 50 x 20 Toyo Open Country. This pressure after consultation with Toyo. They usually rise to over 56 but 50 is the max for that tyre..
Nearly 3 years later ( and a lap and a half) all tyres wearing flat, still with half tread..
I have run Tyredogs on our vans for over ten years, and for the last 3 on car and van. No 2 days are the same...

[discomatt69]

265/65/18 , rear bar, auxiliary fuel, 2.5 ton van, 50psi rear, 40 front 55 van

[Eric SDV6SE]

New defender L663, with 255/50 R20 GY wranglers at 42psi f and rear, 2.7t van, single axle, 55 psi on the van.

Last trip down south west wa, van tyres rose to 57psi, the rears on the car to 46-47, fronts stayed about the same.

Suspension response actually improved with some load on the rear axle.

Using the formula provided: 50psi max for the 255/50 and a load rating of 1150kg, rear axle load of 1800kg, I get: 50/1150 × 1800/2 = 39.13psi as a starting point. Seems a little low for me, but not out of the ballpark.

[coopers1969]

Thanks everyone for your reply’s I will give 50 a go. And report back.

[Briar]

Thanks everyone for your replyÂ’s I will give 50 a go. And report back.
I tow a 3500ATM. Usually about 3300 in touring setup. About 280 on Ball.

I find that 42 in rear is fine but does go up to high 40's esp in summer. However, I lower the front tyres to about 32. Even though the automatic suspension levelling keeps the vehicle level, you can't beat physics. With my setup and 280 on ball, this equates to about 400 on rear axle and MUST therefore reduce front axle loading by about 100-120. By reducing front tyre pressures I'm increasing the front tyre footprint, to compensate for the reduced load. This allows better braking balance. If I put the front tyres at 36 (or whatever), when the van is on I'd have a much smaller footprint on front and reduced handling and braking. Even with 32 front and 42 rear, I'm getting pretty even wear across the face of the tread BUT the rears wear out much more quickly due to the greater load, so tyre rotation becomes more important.

[coopers1969]

Ok so ran 49 and check the pressure and saw 56 so I recon this is ok the tires are rated to max of 50PSI so I don’t want to max them out but may give it a go and keep a close eye on it. Now to next issue
BATTERY AHHHHHHHHH