What does "MAX Pressure mean?

tireman9

Well-known member
There seems to be a lot of confusion about the "MAX PSI" number on the tire sidewall. That PSI number IS NOT the highest pressure a tire can tolerate. Undamaged tires do not "Explode" if you exceed that psi number.
This may help. Read the words so you understand what the "MAX PRESS" is referring to. The "AT" is an important part of the statement. Some tires may not have the word "at" in the statement.
The "Max psi" is the pressure required to support the "Max Load" which is also stated on the tire sidewall.
We tire engineers test our designs at well above the pressure your tires would get to under normal circumstances.
Tire pressure only increases by about 2% for each increase in Ambient temperature of 10°F , so even going up by 90°F or 100°F you should only see a pressure increase of 45 to 50 psi. If you have weighed your RV and consulted the industry tables on Load & Inflation and always inflate your tires to the PSI indicated in the tables for YOUR load, you will probably only see a pressure increase of 20 to 25%. If your TPMS is reporting a greater increase, you need to confirm your load and your cold inflation pressure and your travel speed which in an RV should never exceed 75 mph.
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Related note: I usually recommend that people add 5% to the Minimum inflation found in the tables, to lower the probability of driving while the tires are underinflated.
 

david-steph2018

Well-known member
Tireman9, please explain a couple of other things for new individuals starting to RV.
Some of the terms/questions used by individuals with their tires:
1) What does "cold" mean to take the tire air pressure?
2) If I stop at a rest stop and the tire pressure is now over the max pressure, shouldn't I lower the air pressure?
3) If I start at an altitude of 9,000ft. and set the tire pressure at the max, say 110lbs., then go down to 2,500ft. and will the pressure climb in the tire the next morning? Should the tire pressure be adjusted?
4) And the question going from a lower altitude to a higher altitude?
5) What type of effects does the sun have on the tires, should individuals use tire covers?
6) Does a spray on protective, help the tires?
7) What age is recommended to replace trailer tires?
8) Are certain brands of tires better than other brands?

As you can see, allot of questions that come up in conversations, especially on IRV2, and other forums about tires.
 
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