New air pressure theory?

[two-niner]

So we are assuming Michelin knows nothing about tires and tire pressure.

I am looking a the Michelin RV Tires booklet that came with our Winnebago. It is 32 pages in length.

Nowhere, I repeat, nowhere does it say the inflation tables are the MINIMUM, nor does it say to add 10% "for safety". It's absolutely crazy to have all these "safety experts" say to add more psi than prescribed. Michelin knows nothing?

If you are in Denver, at gross weight (for sea level) and the OAT is 105 degrees, humidity is 92 percent and your check ride pilot says it's okay to take off. Would you? I forgot to mention your weight and balance is extremely tail heavy. Winds calm.

So which is it? Is it Piper's manual or the "expert safety" person okay? By the way you are in a runout twin commanche w/180 hp engines.

Kerry

[AZgl1500]

Originally Posted by wagonmaster2

And then there's the early morning ambient temperature when you're checking the tire pressure for the day. Traveling in the mountains in the fall early morning temps may range from 30 degrees to 50-60 degrees (depending on how early) but the day time driving temps can be anywhere from 60-70 degrees those same days.

Wagonmaster2

The temperature ranges you mention are typical of the Phoenix metro and areas a bit further south about this time of year. ie, fall to early winter.

In the summer, I often arise to see the overnight temps at 90+ and the day time temps reaching 115 or more on occasion.

I once checked all of the tires on my 1 ton dually to be sure all is well. Temps were about 105 when I left home heading to Denton, Texas.

I made it about 31 miles from my house and the right, inside dual blew out. slung tread and carcass around the exhaust, and ripped up the right rear fender. The carcass went flying up and over the top of my GL1500 Goldwing riding on a trailer behind. This even though I had the cruise set at 70 on a 75 mph road.

I carry an IR temperature gun with me at all times, checked the pavement and it was 157*F.

I noted that 3 tires were still holding air and crippled on down 15 miles to Casa Grande and forked over about a grand for 4 new Michelins. I had enough of the Big O's on the truck.

Those tires had given good service around town, but just could not handle the much highers temps and constant high speed driving. Still had 50% tread on them too.

[f14av8r]

Actually, Two-Niner I think Michelin is right on the mark. They give you the recommended inflation pressure. But, they also caution us to ensure we NEVER run a tire under-inflated. So, I think a few extra PSI (10% was a typo, 5% is actually what RVSEF recommends and what I use) is a good idea as I know I'll seldom be exactly right on my loaded weight or cold tire inflation. The minimums are the minimums for a reason but a few extra PSI, while it might very slightly reduce ride quality or traction, will improve my chances of not having a blowout due to under-inflation. Again, just my opinion. I certainly don't advocate gross over-inflation either. There are still plenty of folks out there running at sidewall pressure even though their load doesn't require anthing like that degree of inflation. It's nice to be discussing tinkering at the margins! At least we are way ahead of the game.

By the way, you wouldn't catch me in a Comanchee in Denver with or without a manual but I get your point!

Happy Trails!