Date: Sun, 17 Jul 2011 10:39:02 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Tires And Weight Rating
In-Reply-To: <1912392420.748864.1310867131181.JavaMail.root@sz0063a.westchester.pa.mail.comcast.net>
Content-Type: text/plain; charset="utf-8"
We need to face some reality here. No matter what tire you choose, tire failures can and do happen. They fail due to miss application, improper inflation, over or under, extreme conditions, speeds, road surface, impacts, debris, holes, leaks, defects, etc. Growing up and paying attention to the family cars at an early age there was no such things as cars having unused spare tires and I never saw cars with over 100K until after my dad bought the '67 bus. I remember getting mom to treat it to radials when I was a senior in high school. Heavy-under-tired vehicles just add to the mix.
Choosing and installing tires is only part of owning and using them. Regular maintenance is also required. A tire having tread does not mean it is usable. Tires are assembled components with parts glued and molded together. Sometimes the process fails. Regular inspection can often detect these and true defects will usually be covered by the manufacturer. Goodyear is probably the best as they empower their dealers to make determinations on the spot or over the phone while you wait. My last motorhome had a tire blowout at ~49,000 miles and Goodyear covered it. That same vehicle at ~13,000 miles had a bad case of the shakes and after evaluating three tires out of round (ride disturbance) they covered those. Those were 245/70-19.5 load range F.
Many tires fail due to a leak developing while underway. The leak can be due to a puncture, valve, or rim seal failure. The pressure drops and the tire is now underinflated and thus overloaded. The tire heats up and a failure occurs.
As for the rated weight to actual failure there are simply too many variables. Keep in mind the rated weight only applies at the max rated air pressure. A tire rated at 65 psi holds nowhere near the same capacity at 50 psi. You need the weight to pressure chart from that manufacturer for that tire. A stronger thicker sidewall tire actually needs higher pressure at speed to stay cool as those extra plies also mean extra heat as the tire flexes. Regardless of the tire sidewall construction the deviation from unloaded diameter to the loaded (the bottom flat spot) is fully dependent on tire pressure and size. That is where tread separations become a problem.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of J Stewart
Sent: Saturday, July 16, 2011 9:46 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Tires And Weight Rating
OK, I know I am opening Pandora's Box here, but with all the talk over the years about the correct weight rated tire for Vanagon Westfalias, are there any documented cases of incorrect rated tires blowing and causing an accident? We've all heard the dire warnings about what CAN happen if you use underrated tires, but does anyone really know of a case? Not your father-in-laws next door neighbors cousins best friend, but actual knowledge. And if a tire is rated to carry, say 1700 lbs., at what point will it fail? 1750? 1800? 2000? There has to be a fudge factor designed in here, what is it? Just curious.... Jeff
Jeff Stewart
| 
