Do you run factory PSI on your tires?

[autostick]

Depending on where the car was delivered the stickers would be different. The '79 I have was delivered to a dealer in Wisconsin and recomended 26 psi. The other '79 I had was delivered to a Dallas dealer and the recommendation was 30 psi.

Dallas and most Texas Lincolns require additional air pressure to offset the weight of all the arms and ammo. At the other extreme is God's country, Wisconsin, so close to heaven air pressure is optional.

[MikeJ]

Yes Wisconsin is God's country. Drove up to Door County a few weeks ago and the weather was beautiful 102º when we left Dallas and 51º in the U P.

[thegermanfan]

Dallas and most Texas Lincolns require additional air pressure to offset the weight of all the arms and ammo. At the other extreme is God's country, Wisconsin, so close to heaven air pressure is optional.

you just made my day!

[2sasilverbullet]

Dallas and most Texas Lincolns require additional air pressure to offset the weight of all the arms and ammo. At the other extreme is God's country, Wisconsin, so close to heaven air pressure is optional.

ROFL!!!! How true, how true...

On a more serious note - I put them all at 32 and took her out for a 2 hour test drive at highway speed (what speed, I'm not tellin!) She handled superb! Much better than the mushy ride at 26. I might try them another day at 30 to see if that's still ok. I really want to keep the cold psi as low as possible because of the 105 degree temps around here. Road temps run around 115!!

Thanks for all the input everyone! This was a nice thread for a change, we all played well!

[TonyC]

32 should be your target; but even if you run the 35 the tire recommends, you should still be fine. Radials are designed to expand somewhat when the temps rise; as long as you aren't above the max cold pressure, they won't blow--unless they were defective from the factory.

Barring that scenario, of course, I've run 35 psi in Frankenstein's tires constantly with no problems. Not even El Paso in July blew out any tires.

---Tony

[Dermot]

Remember 'factory' psi meant 1970s tire design factory psi, not 2011 tire psi.
I run 34 in my soon-to-go 1981 Fleetwood Brougham and the car is a joy to drive. Great steering response, good handling. Its two fingers on the wheel in narrow lanes, heavy traffic, high speed.

[TonyC]

True, but who in his right mind would be running 1970s tires in 2011, radial or otherwise? They'd have to have deteriorated by this time.

[Dermot]

True, but who in his right mind would be running 1970s tires in 2011, radial or otherwise? They'd have to have deteriorated by this time.

Very very occasionally I see an old car with tires ready for the graveyard. I was more suggesting that a 1970s door sticker's recommended tire pressure is obsolete now.

[TonyC]

Oh, that thing--yes, of course! I forgot about the stickers on the cars; it would be obsolete for certain. I always tell people not to go with the pressure recommendations in their owner's booklets or the stickers on the cars; always use the recommendations on the tires themselves. Those figures are the most accurate.

---Tony

[2sasilverbullet]

Tony - well I agree with you to a point - "some" manufacturers I wouldn't trust the stickers. But Porsche, BMW, Mercedes to name a few spend a lot of time and money on finding the right psi - I would bank on those to be right, IF you're running the recommended tire size.

[Dermot]

Tony - well I agree with you to a point - "some" manufacturers I wouldn't trust the stickers. But Porsche, BMW, Mercedes to name a few spend a lot of time and money on finding the right psi - I would bank on those to be right, IF you're running the recommended tire size.

Probably the tire pressures recommended in 1970 for a 911 with 1970 tires are no longer appropriate for a 1970 911 with 2011 tires.

[Lee]

I thought this would be a good area to mention the fact that when I received the Coker P235/75R14’s for my ‘62, there were several warning labels included to ensure inflation to minimum 36 psi when being installed on non-radial rims. Probably something their lawyers cooked up, but it is interesting to note that rims designed for radials have different reinforcement areas than for bias plys. Good overview of the subject here: http://sites.sema.org/ext-assets/counci ... itment.pdf

[TonyC]

I'll have to look that link up when I have a better connection, like at home on my computer. I have heard that radial rims have different construction, but the details should be interesting, at least for academic purposes.

On a related side note, I've never had issues with radial tires on Frankenstein's bias rims. Sure, they may flex, but the wheel cover tricks I learned over the years help to mitigate the flying-saucer risk. That said, however, I really have to do some inspection to my left-front wheel. Since that "Killeen Welcome," the cover doesn't seem to hold as it should. I mean, yes, the cover took the hit as well, but even the spare I kept on the wall seems to have trouble holding in place. After a trip to Topeka yesterday, I saw that it was working loose. The tire shop did not notice anything about the wheel, or they would've told me. Also, I made the trip back with no issues...but, maybe there is something.

I personally no longer pay attention to any psi guidances printed on decals or in owner's manuals. As already established, those figures apply only to the tires the car left the factory with and do not apply at all to any replacements over time. My reference point is the cold-psi figure actually molded onto the tire itself; though that is a maximum amount, it is a maximum cold amount, which is calculated by the manufacturer of the tire to accommodate for hot expansion without bursting. If the tire says 50 psi, I'll put in 40, maybe 45. I think 5 to 10 psi below the established cold maximum (but never below 35 psi) is a pretty safe range, and more versatile than sticking to an arbitrary figure which may prove too low for the specific tire to provide its best service.

---Tony

[Dan Szwarc]

I thought this would be a good area to mention the fact that when I received the Coker P235/75R14’s for my ‘62, there were several warning labels included to ensure inflation to minimum 36 psi when being installed on non-radial rims. Probably something their lawyers cooked up, but it is interesting to note that rims designed for radials have different reinforcement areas than for bias plys. Good overview of the subject here: http://sites.sema.org/ext-assets/counci ... itment.pdf

I knew this because I heard this from the guy I bought my 70 Merc from in 1992.

Bottom line: rims properly designed for radials have a bead on the inside of the rim, inboard side, that holds the less stiff inboard sidewalls from collapsing into the rim. My 66 rims lack this bead so no hard cornering.

Maybe I’ll post a pic.

[Mike]

I personally no longer pay attention to any psi guidances printed on decals or in owner's manuals. As already established, those figures apply only to the tires the car left the factory with and do not apply at all to any replacements over time. My reference point is the cold-psi figure actually molded onto the tire itself; though that is a maximum amount, it is a maximum cold amount, which is calculated by the manufacturer of the tire to accommodate for hot expansion without bursting. If the tire says 50 psi, I'll put in 40, maybe 45. I think 5 to 10 psi below the established cold maximum (but never below 35 psi) is a pretty safe range, and more versatile than sticking to an arbitrary figure which may prove too low for the specific tire to provide its best service.

---Tony

The listed psi for the car is based on the characteristics and tire size that was originally intended to be on the car. As long as you're not changing that it's safe to follow that pressure. Tire manufacturers don't know the size or weight of the car the tire is going on so they can't provide any number to follow. Unless it's low profile or some performance tire stock pressure is almost always listed around 32-35 psi so it's safe to stay around there. That being said sometime you get tires that don't have as solid side wall and they don't feel right or wear properly and more air doesn't hurt. I wouldn't be running the under 30psi the 60s manuals say with radials.

The biggest issue I've ever heard about radials on old rims is the way the tires seat is different so they might be more prone to leaking or the tire could come out of position easier if it's low on air.