Tyre pressures

Good day all, I have searched the treads to find an answer to this question but cannot find a definitive one. If you change the wheels and tyres on a 1986 240GLE saloon from a 185x70x14 to 195x60x15 (as per a later 240GLT) do you need to alter the tyre pressures? I have read threads that indicate that the pressure is a function of the tyre size/aspect ratio but I don't know how you determine the variation of the pressure. Alternatively if someone with this size tyre on a GLT could provide me with the data I would be most grateful as I have just had to replace all four tyres and I don't want any unneccessary wear to start straight away!! Many thanks. Regards

I assume you have fitted 15" tyres to Virgo (GLT) rims, they tend to be a bit loose on 14" steels. Tyre pressure for GLT varies with load carried i.e. unloaded to loaded, I have run my GLT estates on 28 front 30 rear unloaded and 30 and 32 loaded with excellent tyre wear. I am a Michelin fan (to my knowledge and experience they actually make round tyres, very few balance weights are ever needed) currently using 196/60/VR/15 'Primacy'. These give me about 25000 miles. Just a final note . The virgo wheels are very prone to alloy corrosion around the tyre bead area and I always... Always insist on the rims being thoroughly cleaned and new tyres fitted with rubber seal solution on the rims. Still with all that I occassionally get a bead leak. Richard

I rune the 205s on these same pressures and everything is fine at that - handling excellent and wear is perfectly even. Mike

Hi Mike, Is that 28 all round? Regards

Most of the time I am carrying a fair weight and run 28F 32R When not loaded 28 all round. Mike

That's good to know... I bought an '88 240 GL which has been fitted with a set of Virgo 15" rims (and, surprisingly, decent Firestone rubber), and have been searching unsuccessfully for the correct pressures. 28 psi front/ 30 psi rear unladen is the same as the recommended pressures for the standard steel rims, which will save me having to put a Dymo label in the fuel filler flap to remind me... Rear o/s tyre is constantly going flat, so I'll get the garage to re-bead it. Useful stuff, thanks guys!

SFSS runs 32psi on all 4 paws (nearly typed "all round" but tyres are supposed to be round) with 195/65/15s on Virgos. Someone on Turbobricks suggested starting with 32psi at both ends and adjusting from there to get the ride comfort level you want; that's the approach I've taken with all my Volvos since then.