How much air would you recommend putting in 265/65r17 tires on a 4 door 4x4 Vigo with a cab on the back? Max pressure says 44psi on the tire. The manual recommends 28 for both front and rear if the tires are 255/70/15 which they are not. The tire shop that put them on suggested 40. Who do I believe?

35 lbs front and rear while still cold

If the wheels/tires are OEM, look at the placard in the driver's door jamb - that should be model specific.

If the 17" wheels/tires have been fitted aftermarket, you will need to compare old:new tire load ratings (which are a v.good indicator of sidewall stiffness) to determine the pressure needed.

Rule of thumb here is: OEM tire load rating - new tire load rating + manufacturers recommended PSI

example:

OEM tires are 255/70R15 111H, new tires are 265/65R17 113V, and the manufacturer's recommendation is 28 PSI:

111-113+28 = 26 PSI

If you have anywhere near 40 psi in your tyres on a Vigo your head will be bouncing on the ceiling and you will not have 100% traction in different maneuvers and they will wear out a lot quicker.

The max rating on the tyre is for safety purposes for a particular use, My Vigo it states 29 psi, loaded or unloaded.

The 29 psi is a ''cold'' pressure as pressure will increase when the tyres warm up in use.

265/65s? On 17" rim? I'd go for 34.

I run 36 on my 245/40/17s.

33 would be where I would start.

Now finding a machine with a gauge that works correctly is another matter. Better to buy a hand held gauge.

You can pretty much guarantee if the Thai shops that sold them says 40 it should be less!

Now finding a machine with a gauge that works correctly is another matter. Better to buy a hand held gauge.

I bought a small air compressor with a gauge on it that plugs into a lighter from Thai Watsadu. Works like a charm.

I have an attachment: a pistol grip with gauge, flexi hose and a chuck I fitted myself. It always reads 3psi less than the hand held gauge.

It's a joy being able to check the pressure in the rear tyre of the big bike now.

If the wheels/tires are OEM, look at the placard in the driver's door jamb - that should be model specific.

If the 17" wheels/tires have been fitted aftermarket, you will need to compare old:new tire load ratings (which are a v.good indicator of sidewall stiffness) to determine the pressure needed.

Rule of thumb here is: OEM tire load rating - new tire load rating + manufacturers recommended PSI

example:

OEM tires are 255/70R15 111H, new tires are 265/65R17 113V, and the manufacturer's recommendation is 28 PSI:

111-113+28 = 26 PSI

Good post correct info if your changing to different profile tyres :-

The correct rule is: Adjust the OEM recommended PSI pressures by subtracting or adding the load rating of the new tyre from the load rating of OEM new tyre.

Examples:

If the OEM tyre is 109S and the new tyre is 112V, and the OEM pressure is 29PSI:

109 minus 112 = minus 3

29PSI minus 3 = 26 PSI

If the OEM tire is 112H and the new tyre is 111R, and the OEM pressure is 32PSI:

112 minus 111 = +1

32PSI + 1 = 33 PSI.

So obviously important to know what the OEM load of your vehicles OEM tyre.