Sounds like a silly question, but does anyone know what psi my tyres should be? Its a MY2010 TDV8, riding on 19" 255/55/r19 pirelli scorpian zeros. The inside of the door reads: 36psi at the rear and 33psi at the front but this is for a fully occupied vehicle I.e 4 adults (no luggage). It's normally only the better half and myself therefore is 36/33psi too much?

The reason for asking is I think my tyres are wearing more in the centre (at the rears mainly) than the rest of the tyre (can feel centre tyre bar) indicating over-inflation..?!

My thinking is perhaps 31psi at the front and 34 psi at the rear when only 1 or 2 adults are riding without luggage or is this too low... Any thoughts?

Thanks fellow ff's

Ray Better to be irresponsible and right, than to be responsible and wrong.

2010 Vogue 4.4 TDV8 Santorini Black, Jet/Ivory interior

Would probably agree with you, all the tyres on my previous RR's wear in the centre on std pressures and 80% of the time it's just me in it.

I Was thinking of reducing the pressures to around what you suggest! 2021 L405 Vogue SE 4.4 V8 DIESEL ~ #17

Last winter I ran 34 at the back and 31 at the front but inflate if high speed motorway...

Inside my door it says 36 front and 42 rear for full occupancy thats what I run with. Mine is a 3.6 tdv8 2008 im surprised theres a difference as they are fundamentally the same car. Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

@ Gaz: forgive the naivety, but why inflate if on motorway? Wouldnt the pressure expand at speed I.e if you were to take a pressure reading whilst tyre is warm the psi reading would naturally be higher (unless riding on nitrogen filled tyres)?

Cheers Better to be irresponsible and right, than to be responsible and wrong.

2010 Vogue 4.4 TDV8 Santorini Black, Jet/Ivory interior

@ Googsy: I could be wrong but I think that's the pressure with 5 adults + loaded to the max with luggage etc... At least that what mine says. Better to be irresponsible and right, than to be responsible and wrong.

2010 Vogue 4.4 TDV8 Santorini Black, Jet/Ivory interior

Hope im wrong because its usually just me in the car so if 33 / 36 is possible without increased wear I will be happy as ride is a little hard. Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

just a slight diversion to the OP; but how accurate are the TPMS readings likely to be?
I ask as the IIDTool shows the TPMS live values and wondered if it might be interesting to monitor if there is a pressure increase with motorway speed

Right just been out in the dark to check and it appears I should have 33 in front and 36 in rear which I cant wait to do tomorrow  Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

@ Googsy: 33 front and 36 rear is rthe ecomended pressure with 4 adults in the vehicle. If its normally just youself, you may want to lower it a little, say 31/34...?

Ive been riding 33 front and 36 rear for a while now and tyres appear to be wearing quick in the centre indicating over-inflation! Im going to try 31/34.

Still no idea if 31/34 for just 1 or 2 adults is ok though, I'll probably discover excessive wear on the walls after a few hundred miles  Better to be irresponsible and right, than to be responsible and wrong.

2010 Vogue 4.4 TDV8 Santorini Black, Jet/Ivory interior

When I am going up North on the Motorway I normally have four in the car so inflate for that reason. High speed driving requires correct pressure while local driving is fine on slightly lower pressures.

In the past I used to go a bit higher on tyre pressure as it was supposed to reduce fuel consumption. So max weight pressure plus 0.1 bar or 1.4504 psi.

These days I just stay with the max. pressure of the car.

A bigger worry is the accuracy of the measurements. The gauges on petrol station compressors or cheap gauges (like what I use myself as my little compressor is way out) are not the most accurate nor calibrated. Who knows how far you are out.

As for the TPMS, indeed, how accurate is that ?????

Using nitrogen iso air is a great way of reducing the pressure build up when tyres get warmer (sun/highway driving etc.).

In light of the above, my suggestion is, just keep it at the max. load pressure so you are always ready for it, plus that you lose a bit of pressure between tyre pressure checks as well usually so there is more margin.

Too low pressure is quite bad for the tyres, especially the side wall and fuel consumption. Too high at the max. weight pressure (unless the gauge you used is way out like my little compressor) is less likely to happen and with the slow decrease of pressure you will probably see you going towards the "optimum" pressure while using it between "fills".

If you do see middle tyre wear, then of course you are (way???) too high in pressure !! Time to go to a tyre place and check your own gauge against a calibrated one. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

i have also found that garage gauges are all different,. the best way is to keep a stick gauge in the car. the slide out type, and pump them up in the garage/your driveway and check on the separate gauge. -stick some dymo on it with pressures etc.
only a fiver...
http://www.ebay.co.uk/itm/PCL-Tyre-Pressur...43ab2a3637

Just put 33 and 36 in this morning makes a great differnce car feels more comfy... Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE

just put 31 & 34 in mine, what a difference 2psi makes and only 1 or 2 onboard! Will inflate up when car fully loaded though. 2021 L405 Vogue SE 4.4 V8 DIESEL ~ #17