mmm
Like I said, higher pressures are desirable, even necessary, on the low profile tyres mentioned by many people here, but I have pretty serious reservations about them on standard wheels and tyres on a 504, especially as the Michelin XZX tyres on the particular car in question are pretty old too.
I've used 504's with up to 34 psi all round on long fast trips with heavy loads, but even this is pretty close to the useable limit in them I reckon. For the sort of driving that James is suggesting (suburban / round town.etc) I think 30 psi remains the best bet. Apart from potential tyre wear issues the extra hardness will putting more stress on just about everything else, from suspension components to exhaust and engine mounts, none of which will be exactly "new" anyway given the age of the car.
Cheers
Rod
Like I said, higher pressures are desirable, even necessary, on the low profile tyres mentioned by many people here, but I have pretty serious reservations about them on standard wheels and tyres on a 504, especially as the Michelin XZX tyres on the particular car in question are pretty old too.
I've used 504's with up to 34 psi all round on long fast trips with heavy loads, but even this is pretty close to the useable limit in them I reckon. For the sort of driving that James is suggesting (suburban / round town.etc) I think 30 psi remains the best bet. Apart from potential tyre wear issues the extra hardness will putting more stress on just about everything else, from suspension components to exhaust and engine mounts, none of which will be exactly "new" anyway given the age of the car.
Cheers
Rod