Radial tire pressure

The tires have 35 psi printed on them. I found this to be too low. I run 50 in the rear and 45 in front with my heavy Fordor. Go for a drive of about 10 miles then touch the sidewalls. It they are hot to the touch then the pressure is too low. The sidewalls should be warm, but not hot. Disclaimer: Since the tires have 35 psi printed on them, you are on your own when increasing the pressure. Modern tires that are not damaged, for instance by running on them when they are flat, can withstand 200 psi. But I am telling you what I do and not recommending that you do the same.
 
I tried 40psi in my 4.50-500x19 American Classic radials and found the ride a little on the harsh side. Drop down to 35psi and the ride is much more to my liking.

I suggest you try different pressures on your car and find what you like.
 
I’m guessing the different answers have a lot to do with the different weights of these cars. Neil’s car is pretty heavy as I recall.
 
My Coker 19" radials say on the sidewalls: Max 44 psi. I run mine at 40 psi, works for me.
 
If you run the car’s weight and the tire load rating through tire pressure calculators, usually you come out with 25-35 psi as the recommended pressure, depending on the body type and expected passenger weight. I did this for the American Classic 21” radials.
 
Tirepressure is all about load on tire, and maximum speed used.
All not to overheat any prt of tire-material, when driving the speed constantely.
So if you give tire specifications, this "pigheaded Dutch selfdeclared tirepressure specialist" will make a pressure/axleloadcapacity list, with build in reserve.

Then you only need to determine the axleloads acurately and s3arch them back in my list, the most tricky part, and your responcibility.

Need next.
1. Maximum load or loadindex.
2. Kind of tire to determine the maxloadpressure.
3. Speedcode, less important.
 
My Fordor has a heavy metal trunk in the back loaded down with heavy tools and parts. Another heavy tool box in front with oil, coolant, and more parts. Plus all the added body insulation and tools under the seats. Did I mention there are lots of tools. With the tire pressure I run the radials still perform like radials.

Again, it comes down to heat. High temperatures can limit the life of a tire and ruin the inner tube. Too much flexing leads to too much heat.
 
nkaminar said:
My Fordor has a heavy metal trunk in the back loaded down with heavy tools and parts. Another heavy tool box in front with oil, coolant, and more parts. Plus all the added body insulation and tools under the seats. Did I mention there are lots of tools. With the tire pressure I run the radials still perform like radials.

Again, it comes down to heat. High temperatures can limit the life of a tire and ruin the inner tube. Too much flexing leads to too much heat.
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I just got a set on this weekend and filled them to 35. I have not went for a test drive yet but the tires look underinflated at 35. I will see if they get hot after a 10 mile ride and I have a feeling they will......next will be increase to 45. I tend to run my modern cars at max psi.....tires last longer and better MPG. You do get a harder ride but I will take that for more tire life.
 
If you remember back in the olden day when radial tires first came to use in the USA they all bulged. They appeared to be low on air pressure but were not. My new American Classic radials set at the max of 35 psi also have that bulging look where the rubber meets the pavement. Have to believe modern radials have stiffer sidewalls, but not the American Classics.
 
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