Packard Forum Index » Post-War (1946-54)

Hello everyone! I'm curious to what pressures everyone is running in their tires. I'm running 235/75 R15s on my car, and I'm running 28psi in the front and 32 in the rear, but I really have no idea if those are good pressures for the car.

I usually run 35 in the front for easy steering and a little sharper handling. (sharp is a relative term for a bathtub Packard) At the rear I'd pump in 28 for a normal sedan, but for a long wheelbase heavy car 32 would be fine.

For radials use the tire makers recommendations. If they don't publish go to a modern car with similar weight and aspect ratio (xxx/75 ...) and use that which is generally in the 32 to 35 range.

The Packard numbers are for bias ply and should not be used with radials. The angle of the cord sidewall of the bias ply tire creates a response to pressure that is more supportive than radials which is why they use lower pressures.

I would also recommend using the pressure specified on the tires themselves.

The tire pressure printed on the tires is typically the MAX rating that they should be and not intended to indicated the pressure to be used.

When I first started running radials, I'd notice that I'd have plenty of center tread left when the sides wear wearing out. When I started driving pick-ups as a matter of course, I also started running the max pressure in the tires. If it said 44PSI on the sidewall, that's what I ran. I noticed also that my tread seemed to wear more evenly that way.


Go out, try something, make notes of how it works, and have your own experience.

When the tires warm up during driving, you will then be exceeding the manufacturer's rating which is a safety issue and the reason the rating is there.

I have yet to figure this out, at some point I'll get some tire chalk and see how they wear at different pressures. For the time being I'm using about 28 PSI in 235/75 R15 on my 55 400, but not to say that's the best number.

As HPH mentioned, if you want to get even wear on the tires, the best way is to apply tire chalk, then drive the car back and forth on a level surface. It will quickly show if you are under or over inflated. That's how I do it on my overlanding rig....I found that about 38 on the front and 35 on the rear is perfect for my truck. Can't rely on someone else's experience because vehicles are different weights, running different tires, etc.

I'm not sure what my Panama is at currently, but I've been running about 28-30 front and rear on Diamondback tires. I'm not doing any long distance cruising. Just stuff around town. And the tires are comfortable and track straight. I have not done the chalk test, but I put so few miles on the car that these tires will last for many, many years.

-Kevin

I'd have to look again to be certain, but I'm awfully darned sure that the rating on the tire says "cold" beside the number.


I'm still trying to figure out why Harley-Davidson sells its bikes with bias ply tires still. It's definitely a different breed from a car tire.