If I'm at about 17 psi on my 33's can I safely drive about 40 miles on paved roads to get home? Highway speeds?

 

I wouldn't. When you are aired down your sidewall flexes more at the bottom of the tire. As you drive around and the tire rotates the sidewall is constantly flexing as it reaches the bottom, then flattening out as it goes back to the top. This constant flexing stresses the sidewalls. At low speeds when you are wheeling you aren't getting a lot of revolutions, but at highway speeds its flexing back and forth rapidly. This will cause it to heat up and weaken the sidewalls.

Does this mean it will fail? No guarantee one way or another, it would depend on your tire brand, age, and all sorts of other variables. So I generally wouldn't do it. Someone with more experience may have more advice.

 

you may be okay if you're only going a short distance at slower speeds 30 or less, with minimal corners. I've ran 20 on the freeway, but drove only 45 in slow lane, extra slow around turns on town streets and highways.

 

after wheeling when i go back to the hotel which is a 4mile highway trip i just drive back aired down already at 12psi. consider this, if your tire can stay seated on your wheels getting banged up against rocks, why cant it handle a short trip?

 

short answer: probably not.

However I have done 80mph on the highway at 18psi and it felt solid. Probably not the smartest but my compressor crapped out on me and I just generally drive like an ass

 

The correct answer is: NO! Especially at highway speed.
It is bad for the tires, and damage is cumulative.

 

No, too low of a tire pressure can cause a blowout at high speeds (above 35-40) due to overheating of the sidewalls. It's mentioned in the manual but I've had it happen while in my buddies jeep.

 

look up ford explorer /firestone tire debacle - same thang

 

Quite a difference of opinion here, interesting debate.

 

While on a trip in my old WJ with several international vendors/manufacturers off-roading through BC, we were in the dirt aired down to 15-20 psi and then hit the highway. We ran at about 50-55mph for about 30 miles or so.

Zero problems. The tires were on the vehicle until the dayI sold it, over 25,000 miles on the tires. They also traveled back from BC, Canada (properly aired up) at speeds in the 105-110mph range with zero problems or vibrations. (along that LONG, FLAT section of interstate from Utah into Colorado.



What does "aired down" constitute? 25psi? 20? 10? lower?

I feel comfortable at 20psi on the highway for short distances at reasonable speeds, at least until I can air back up.

I'd think it would have to be a case by case situation where you compare the load rating of the tire along with vehicle weight, speed, and distance.

Surely I am in agreement if you are at 10pis and below. 15? probably still in agreement. 20? I think 20 would be just fine. (this would assume you are using at LEAST a tire that has specifications equal to the oem tire.)