Quote:
Originally Posted by cfg83
............(CapriRacer, sorry in advance if I am misquoting you)
I agree. CapriRacer commented on Max PSI. I believe that he said something akin to "as long as you drive the way we are driving, sidewall max PSI is ok, but inflation above Max tire PSI is not ok". ...........
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Sorry, but that isn't quite right. I hope I am not contradicting myself (I didn't peruse the entire posting), but tire manufacturers do not test above what is known as the "rated" pressure, which for passenger car tires is 35 psi. What is written on the sidewall is the maximum allowable pressure - and the word "allowable" has some special meaning in this context. It assumes that the tires are going to be used in a high speed situation - like the German Autobahn - where the road is designed for such usage - a smooth, debris free, no pot holes, etc surface, where the additional pressure is used to reduced the heat buildup in the tire.
Also, ALL vehicle testing is done at the vehicle tire placard pressure.
Further, while it is true that NEW passenger car tires have bursting pressures over 200 psi, this is a one time event. If you read up on fatigue resistance, you'll find that if something is loaded repeatedly, like rolling the tire with a load, the fatigue resistance drops dramatically. In the range of value normal for tires - 10
6 cycles - the fatigue resistance is 20 to 25% of the one time value.
Further, I have seen some old tires that burst at 35 psi. Admittedly there were 20+ years old, but the issue is that they deteriorated over time.
But let's look at the specs for the EV1:
Quote:
Originally Posted by cfg83
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The tires are this vehicle were NOT standard passenger car tires. They were specially designed for this application knowing that the placard specification was for 50 psi. In other words, the tires were specially designed to be able to hold that kind of pressure.