check out the new remote control Jockey Wheel SmartBar rearview170 Beam Communications SatPhone Shop Barrington Coast Airshow
Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Tyre Pressures.


Guru

Status: Offline
Posts: 5420
Date:
Tyre Pressures.


Like my car, my van runs 265/75 R16 tyres, and when I replace the car's tyres I transfer the tyres that are on the car to the van to run them out. Tyres max load is 1550kg, max pressure is 80psi. Since I've been on the road I've been playing around with several different brands, looking for one that best suits.

Today I negotiated a very good price on 4 Toyo Open Country tyres, so first the dealer swapped the car's wheels (Maxxis . Poor) onto the van, as I had asked, but I then noticed that he was putting air into all 4 tyres.

When I asked about this he insisted that anything under 60psi was totally unsuitable, and he got quite toey when I told him "40 psi".

The van is dual axle and I run 3150kg GTM (weight on wheels) so put 40-42psi in tyres. This pressure is lowered on rough dirt roads, but there is no way that I was going to allow the dealer to put 60psi in my tyres, as he had suggested.

My concern is that he may be offering this incorrect advice to others who have no understanding of tyre pressures. Cheers

 

3756F004-E8C3-4549-9671-B1ED19B74526.png

 

 

 

 



-- Edited by yobarr on Thursday 21st of September 2023 06:57:44 PM

Attachments
__________________

v



Guru

Status: Offline
Posts: 7573
Date:

I don't tow, so car only. 255/60r18 x 6 (2 spares).

 

When I got new All Terrain tyres. They pumped them up to 45psi. I said that is far too high. Reply was, 'everyone pumps them up that much'.

 

After some arguing, they were going to reduce the pressure. I said I will do it myself.

 

They really must have been totally blind to my air management set up, so obviously I don't take air seriously! as two wheels had to go in the boot, which they had to take out at the start of the job.

IMG_3018-compressor-#3_121311.jpg

 

normal__MG_2513.jpg

 

Dropped back to 32psi as car states when home, after bone jarring ride.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Guru

Status: Offline
Posts: 1306
Date:

Sometime back I came across a table x-referencing caravan weight and wheel size with
recommended tyre pressure. Think may have come from Colin Young.

__________________

Ex software engineer, now chef



Guru

Status: Offline
Posts: 724
Date:

A few months ago, I found the calculations for correct tyre pressure based on the actual wheel load, and the maximum allowable load at its maximum tyre pressure from the tyre's sidewall.

I recently purchased some Toyo Open Country tyres for my vehicle and after collecting the car, I checked the pressures and noticed that the pressures were a few psi higher than I ran the old tyres. But doing the tyre pressure calculations, even though the new tyres had a higher max load rating, that rating was a higher max allowable pressure. Based on vehicle wheel loads, it seemed that the tyre fitters pressures were about right. By coincidence, I suspect.

Also, simllarly I checked the van's recommended tyre pressures on its tyre placard, as compared to the tyre pressure calculations. Guess what, if I take account of the extra 20% factor for the van's independent suspension system that is fitted, the tyre placard pressures matched my calculations.

__________________


Guru

Status: Offline
Posts: 5420
Date:

deverall11 wrote:

Sometime back I came across a table x-referencing caravan weight and wheel size with
recommended tyre pressure. Think may have come from Colin Young.


 Simple way is divide tyre's maximum pressure (80psi) by its maximum weight carrying capacity. (1550kg) . Result in this case is .051.

Now multiply weight that is carried by that wheel (780kg) by .051 to get pressure of 40psi (39.78psi). Easy stuff.Cheers



__________________

v



Guru

Status: Offline
Posts: 7573
Date:

So on my Land Rover Freelander (Parent of Evoque), they are small cars (they have big wheels for their size).

Tyres 50psi max / max load 1120kg = 0.0446

x max 1360kg / 2 (rear axle) = 30.3psi / 29.2psi front.

Tyres currently when starting the car are at 31psi.

default_146~2.jpg

Over winter were about 29 - 30psi when starting. They warm up about 2psi around the city, also basically nothing in the boot.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.



Veteran Member

Status: Offline
Posts: 46
Date:

I use Cooper AT3 tyres on the BT50 which I run at 40psi when on sealed roads. I think the pressures must be about right because the pair on the front have done 108,000km so far (they were on the rear until 6 mths ago). Approx 5% of that towing. I could probably legally get about another 10-15k km out of them, but I will replace very soon as with any tyre the grip decreases a lot when there's only a few mm left. Rod

__________________


Guru

Status: Offline
Posts: 7573
Date:

& if you swap sides the worn AT tyres will be quieter.



__________________

Procrastination, mankind's greatest labour saving device!

50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us
Purchase Grey Nomad bumper stickers Read our daily column, the Nomad News The Grey Nomad's Guidebook