Tire Pressures

[Christopher J. Bunsey]

On my 76 the door tag says 20lbs. in the front and 26lbs. in the back. Does that still work for todays modern tires?

Thanks!

[Jack H.]

Re: Tire Pressures

Tire pressure recommendations are generally based on the original tires supplied with the vehicle. When you make a significant departure to newer model tires, look at what the tire mfgr recommends for inflation (ususally embossed in the side wall) or take the advice of the selling dealership. Different tire construction and geometry can significantly affect target inflation pressure range.

[Christopher J. Bunsey]

Re: Tire Pressures

I am running Goodyears now, and am curious what types of changes in performance you get when you add or subtract tire pressure?

Chris

[Dave F.]

Just to get the ball rolling...

Drag racers would deflate the rear tires for better traction, and over-inflate the front tires for less resistance. I believe the major influence on performance and appropriate tire pressure has much to do with tread design and tire construction, therefore referring to the manufacturers recommendation seems more applicable than the salesman at the tire store. He will most likely look at the maximum recommended pressure stamp on the sidewall, and give you a number close to that.

[Dick W.]

Re: Just to get the ball rolling...

I think with modern tires and 20 or 26# pressure you are playing a very dangerous game. I would expect to see shoulder failures similar to the Firestone/Ford fiasco. Deffinite underinflation. I think that with a P metric tire you will get your best wear and performance somewhere in the 35# range. Duke can speak better on this issue.

[Duke W.]

Re: Tire Pressures

Those are "comfort pressures" and are probably safe with a modern radial tire with at least the same load capacity, however, these pressures will yield sloppy sloppy steering response, high rolling resistance, which reduces fuel economy, lower tread life, and greater chance of a tread separation, especially on low speed rated tires.

For best all around performance I would recommend starting off at 32 psi (cold) all around. Lower pressure will probably yield a little less ride harshness, but have the downside outllined above.

Higher pressure up to the maximum cold pressure placarded on the tire sidewall is okay, if you want to experiement.

Duke