Incorrect Information re: Tire Pressure in Efficiency Mods

[euromodder]

Originally Posted by ktaylor

I don't recommend going passed the sidewall max but at the same time a lot of people in the forum have. I'm keeping my tires to 5psi below sidewall max just in case. I'd rather be on the safe side than have one of my $225 tires blow apart and possibly kill myself...

Sidewall max. , max. rated load, and max. rated speed is what the tyres are tested for - going beyond that, you're venturing into the safety margin that's been built into the tyres.

Unless you buy some Chinese junk tyres that won't even pass the tests at the rated maximums.

Underinflation is a bigger risk.

[ktaylor]

That's true. Higher than the sidewall max puts you in the safety cushion set by the manufacturer. Realizing that tires heat up as you drive increases pressure is something to keep in mind also. The pressure in my tires has gone up by 5 psi after my 1.5 hour commute so I leave my tires 5 psi below sidewall max as a precaution. I'm leaving my motorcycle tires at the recommended rating though. Fuel efficiency on my bike is good enough for the girls I go out with lol

[PaleMelanesian]

At higher inflation levels, the tires tend to heat up less. There's less flexing in the sidewall to generate heat.

[Frank Lee]

Originally Posted by ktaylor

That's true. Higher than the sidewall max puts you in the safety cushion set by the manufacturer. Realizing that tires heat up as you drive increases pressure is something to keep in mind also. The pressure in my tires has gone up by 5 psi after my 1.5 hour commute so I leave my tires 5 psi below sidewall max as a precaution. I'm leaving my motorcycle tires at the recommended rating though. Fuel efficiency on my bike is good enough for the girls I go out with lol

That is quite unnecessary. For one thing, mfgs have taken that into account and that is why they recommend only checking pressure on cold, undriven-on tires AND THEN they say DO NOT bleed tire pressure down if you check them hot!

For another thing, burst pressure is up around 200 psi so no, if sidewall max is 41 and it goes to 46, it won't blow up.

[Sularus]

Frank Lee, not to doubt you, I know you are very informed about automotive matters, but I have always wondered about tire burst pressure. Can you guide me where to find that information.

I hope I did not come across as sarcastic. I am not trying to be.

J

[ktaylor]

Originally Posted by Frank Lee

That is quite unnecessary.

That may be true but as you increase the pressure and decrease the flexibility of the walls, stress concentrations amplify due to impacts from potholes, sudden bumps, etc.

I imagine the safety factor build into tires must be around 2-3 times max sidewall, but as I said before, I'd rather not risk it. There doesn't seem to be enough specific information on individual tire types to support or refute any arguements about it. Everything is just word of mouth from experience.

[libertyftw]

iv'e run 40psi with a max recommended of 32psi for years with all terrain tire with no adverse effects...don't plan on changing either...

[Frank Lee]

At what point will a truck tire burst from overinflation?
Most new or undamaged medium radial truck tires can withstand three to four times the recommended pressure before bursting. In fact, the rim usually fails before the tire. ITRA has conducted several burst strength tests on new and used medium radial truck tires with special reinforced rims. The tires were pressurized with water. Most recently, three new tires and 13 used tires were "burst tested" with the lowest pressure burst recorded at 300psi and highest at 540psi for an average of 420psi. All of the test tires failed in the bead area.

Tire pressure mpg tests - tire inflation - Page 2 - PriusChat Forums

http://www.officer.com/web/online/Editorial-and-Features/Driving-Under-Pressure/19$27281

I dunno, if you google it the results should be the same as when I google it.

[CapriRacer]

While we are waiting for Frank, folks may want to read up on fatigue and consider how that engineering principal applies to the bursting strength of a tire:

http://en.wikipedia.org/wiki/Fatigue_(material)

[Frank Lee]

What are you waiting for from me?