TIRES PRESSURES

[lepic56]

HI

I JUST GOT A 1951 DODGE CRUSADER (CORONET),, I HAVE AMERICAN CLASSIC RADIAL TIRES AT 35 psi,, BUT THE SHOP MANUAL SAID""  25 psi  SO WHAT IS CORRECT? ,

I BELIEVE IT'S THE SHOP MANUAL THAT RULES, 

[Dodgeb4ya]

Follow what the tire manufacturer states.

[Plymouthy Adams]

pressure are greatly different between bias ply as was factory when your car was built and the modern radials...as B4Ya says, default to the tire makers chart..

[lepic56]

I JUST CHECK THE WEB SITE FOR AMERICAN TIRES,,  IT IS WHAT THEY SAID,,,,,,,

Recommended tire pressure is 35 PSI, and anything below that pressure can lead to inconsistent wear or tire failure.

THANK'S FOR THE EXCELLENT ADVISES..?

[Los_Control]

I will tell you my theory I learned while was in the tire business. But I dealt mostly with modern radials, not sure how much is different between bias and radials.

 

The proper amount of air in the tire, is the amount that is needed to carry the load.

Just saying, If the left front tire on my hoopty goes down to 20 pounds psi, and the tire is squatting, it is under inflated.

Same time, if it is not mounted on the hoopty, then it has enough air to carry the sidewalls and is not underinflated.

The air pressure is directly related to the amount of weight the tire is carrying.

 

A modern tire may say max pressure 35 psi.

If you put 35 psi  in then and mount them on a 2 ton truck and add weight, they are over loaded. The sidewalls will squat and down the road the tires will fail.

If you put the same tires on the front of a hot rod roadster, very little weight on them, maybe 20 pounds psi is all you need to carry the weight?

 

Only saying, it is the air pressure that holds up the tires, You need your tires side walls to stand up and take the load.

 

The max air pressure on the side of the tire is same as a 1 ton chain hoist, you can lift anything up to 1 ton, over that you are on your own. But you can lift any weight you want under 1 ton.

 

If your tires say max 35 psi, you can run less then that, just make sure your tires sidewalls are standing up to the job.

You may find that 28psi or 30 psi, gives you the best ride and the tires work best ... you just need to play here to find what you like. 35 psi in same situation may ride like a wooden buck board.

 

Even though I am used to working with radials, I see no reason why bias is any different on weight and air pressure.

[ptwothree]

Very well said.  A lot of people just see the 35 psi, or whatever, and run that.....silly people!  I like 30 psi 

[Sharps40]

Chalk the tires.  Roll the car.   Look at the chalk left on the tire.  Add or remove air.   Chalk and roll again.  

 

When the chalk is being removed evenly across the tread you have the right pressure.  

[kencombs]

28 minutes ago, Sharps40 said:

Chalk the tires.  Roll the car.   Look at the chalk left on the tire.  Add or remove air.   Chalk and roll again.  

 

When the chalk is being removed evenly across the tread you have the right pressure.  

Agreed.   And , as a double check, on a warmer day, not necessarily hot, but not near freezing, take a 5-10 mile drive at normal speed.  Check the tire temp across the tread in 3-4 spots.  If near the same, you're good.  If hot on the outside, at pressure a few psi at a time.

[Adam H P15 D30]

I run max sidewall pressure on the front tires, makes the steering a little lighter.  Most never drive their old cars enough to wear out a tire due to over inflation, might as well make the steering a little easier.

 

Adam

Edited November 14, 2019 by Adam H P15 D30