Tyre pressure conundrum.

[Thingy]

Following on from an earlier thread of mine, I changed my tyres from the weary Dunlops to BF Goodrich At KO2 and today have had a small surprise. Having checked my pressure for the first time since fitted, I found that ATS had put 42 psi in the front and 45 psi in the rear. My book states for up to 5 people the pressures are 32 and 35 respectively. Thinking that ATS had made a genuine mistake I was going to ring to ask if there was any reason but before I did, I trawled a couple of 4x4 forums. It seems Im not alone. Goodrich are telling some to stick to manufacturers plate and others to use up to 55psi. There really doesnt seem to be a pattern. There also does not seem to be a definitive answer and indeed they are wide ranging. Assuming therefore that ATS havent made a mistake, whats are your considered opinions on this?

I also know some of you have had Goodrich and indeed on Shoguns, again opinions please.

 

[Dustydog]

Thingy,
I had BFG A/Ts for five years on my previous Sorento. I always ran them at 35psi exactly as per the Kia handbook and indeed on the vehicles ID plate. Manufacturers prescribe tyre pressures for reasons like suspension, loads anticipated etc. I am not aware that BFG have ever advised different psi to a vehicle manufacturer’s recommendation.
They were good tyres. Lasted high mileagesbut were slightly noisy. The 4x4 web sites are written by amateurs and maybe some are running higher pressures for boggy off-roading.
I’d stick to the vehicle manufacturer’s pressure.

 

[Thingy]

Thanks Dusty. Thats what I thought. You have to wonder why the fitter increased by 10psi across the board. I dread to think what he torqued my wheel studs at. Im off to check................

 

[otherclive]

Whenever I have tyres changed I always tell the depot what pressure to use and then check them myself after a couple of hours at home. Be surprised how often I’ve had to adjust them.
Go by the makers recommendations for pressure and loads.

 

[CustardAvenger]

Whenever I have tyres changed I always tell the depot what pressure to use and then check them myself after a couple of hours at home. Be surprised how often I’ve had to adjust them.
Go by the makers recommendations for pressure and loads.

I always ran the recommended pressure for my old 2.0D Volvo V50 of about 32-35psi (I forget the actual figure) for the car + driver and 1 passenger, when I first got it, but when the front tyres needed replacing they had worn as if the tyres were under-inflated; wear more on the shoulders and not across the centre. it was identical on both front tyres, and there was no tracking issue.

Always ran at 39/40psi after that, the pressure for a full load. Continue the practice now, running at the 39psi 'Eco' and/or max load pressure for my XC60.

 

[Lappy]

Thingy,
Are you sure your handbook says 32psi front and 35psi rear ?
I have a 2016 Shogun SG3 and my handbook states fully loaded pressure to be 3.2bar front and 3.5bar rear.
I am not too sure if 3.2bar and 3.5bar equate to 42 and 45psi respectively.
Regards,

 

[otherclive]

Isn't there a label somewhere on there car which gives tyre pressures in various load states. Often found on the B-pillar drivers side, but can be elsewhere. Most cars Ive had in recent years have had such a label, even my 1995 Pajero which was in Japanese script too.

 

[Lappy]

Thingy,
I should have said on my previous message that my tyres are 18"
I am not sure if yours may be 17" and therefore the pressures will be different anyway.
Regards,

 

[Thingy]

My book gives three sets of pressures, Ill dig it out tomorrow but the sets are
Up to 5 people
Fully Loaded
AT Towing (which I assume is All terain)

I did check with ATS and their Autodata program and they confirm 32F and 35R. We arent talking fully loaded, only the first set of up to 5 people, and yes, I have 18s.

 

[otherclive]

My book gives three sets of pressures, Ill dig it out tomorrow but the sets are
Up to 5 people
Fully Loaded
AT Towing (which I assume is All terain)

I did check with ATS and their Autodata program and they confirm 32F and 35R. We arent talking fully loaded, only the first set of up to 5 people, and yes, I have 18s.

Haven't you been able to find the data label on the car? Somewhere else it could be apart from B pillar is behind fuel flap.

 

[Hutch]

Thingy,
Are you sure your handbook says 32psi front and 35psi rear ?
I have a 2016 Shogun SG3 and my handbook states fully loaded pressure to be 3.2bar front and 3.5bar rear.
I am not too sure if 3.2bar and 3.5bar equate to 42 and 45psi respectively.
Regards,

Hi Lappy, 3.2 bar = 46 psi and 3.5 bar = 50 psi , my 3 .0 litre Vectra, would run at these pressures when towing.
Edit, These conversion are from Kwik Fits pressure charts.

 

[Gafferbill]

.....tyre pressure is variable with temperature.
ATS may have inflated your tyres on a cold day and you may have taken a measurement from hotter tyres.

 

[Thingy]

I agree, a certain variability, but not 10 psi, thats excessive. I can only think they inflated them to maximum. Went up north to a funeral yesterday and did 300 miles on the right pressures, ran fine so I think thats the answer.

 

[Thingy]

Haven't you been able to find the data label on the car? Somewhere else it could be apart from B pillar is behind fuel flap.

I know where it is, its on the drive with the handbook, I was upstairs in my PJs when I wrote it.

Lappy, both my handbook and doorplate state as follows
265/60/R18

Up to 5 people 2.2F 2.4R.........................31.90PSI and 34.80 psi, I use 32 and 35 psi
Up to Max Load 2.4F 2.8R..........................34.80PSi and 40.61psi, I use 35 and 40psi
At Trailer Towing 3.2F 3.5R.............................46.41psi and 50.76psi, Never used it.

Im thinking I may use the max load setting as these Goodrich do seem a little soft at the lowest set.

 

[Dustydog]

Thingy

No no.
Pleas stick to the car makers recommended pressure,.
See this
https://forums.lr4x4.com/topic/61544-reccommend-tyre-pressure-for-bfg-at-2457516/

 

[otherclive]

I’ve had a Pajero, Disco2 and Gen1 Sorento and I fitted all terrains to all three cars and ran them at makers pressures. Apart from the good performance of the BFGs off road compared to Falken or Yokohama AT where I did have to adjust pressures on road all ran at car makers pressures.

 

[GD485]

Tyre pressure can be an MoT failure if it's not within the makers spec.
Police accident examiners check the pressures of cars involved in incidents.
Surely with the pressures that high solo driving is going to be a bit harsh.
I think the fitter was having an off-day and though he was working on a truck.

 

[Hutch]

I know where your coming from but, You cannot have an off day if someone is paying or a service. Changing tyres and wheels you must have a chart of pressures and wheel bolts /nut to go by for car types.

 

[Brasso530]

Gd485,As far as I'm aware your car will not fail the mot for incorrect tyre pressures.