Hi,

What is the appropriate tire pressure for my 225/60/15 front/rear Magnum 500? When does it become too much?

Thanks!

 

Depends on the tire. I run mine at around 38

 

it becomes too much when you have a little too much in it already.
it'll cause your tyres to bulge on the inside and rub down uneven. new tyres soon.
too little is very bad for gas mileage and rubbing/halndling as well. but I'm lower than 67m302. i run at 2.3bar (33psi)

 

I run 32 in mine. It has Magnum 500 with BFG tires.

 

I have the Radial T/A in 225/50/15 FYI.

Thanks!

 

I would personally use a tire pressure for a similar sized car that uses the same size tires. Reason is that the sidewall listed pressure is the maximum pressure and is appropriate for the maximum load that the tire is rated for. Most cars are nowhere near the maximum load and would therefore need a lower pressure than what is on the sidewall. That is why the car manufacturer recommended pressure doesn't match the maximum pressure on the sidewall. I went to the Firestone website and pulled up a 1988 5.0L Mustang which came with P225/60VR15 tires because it is similar size and weight and it listed the recommended inflation pressure as 30 psi front and rear. You can have a look here.

 

I would guess at 32-34. 65-66 cars are very light, so any more is probably going to be too much. 109jb's method is a good start, but the Ford recommended pressure is going to be a little lower than optimal, designed for ride quality rather than handling and economy.

Try 34 and see how they wear. If you notice they're wearing down the center of the tread faster than the outside edges, drop to 32 and keep monitoring.

 

Tire pressure will also affect ride quality and mileage. Generally speaking more pressure will result in crisper feeling handling and a stiffer ride, but with better mileage.

 

I have not done that in a very long time so I am probably way below. Thanks for the information!