Quote:
Originally Posted by sdkid
I have been told at training schools that the spec in the door post or owner manual is what to use. The spec on the tire is the max pressure that the tire can handle while driving wide open on the autobon. Don't know if thats the truth , but is what I was told at a chrysler training class.
|
The main reason this is what you are told, (the fed gov also preaches the sticker as the final word on tire pressures) this way, FORD, CHEVY... whomever, is responsible, and the feds feel a car's usefull life span is only 5 years anyways (anyone writing off a car on taxes knows this) so tire technology will only increase a little, and you are safe to go by that old info on the sticker.
Quote:
Originally Posted by jorgensensc
THere is the problem with "tech" schools (no offense towards you). If you are running different than factory tires, or as in our case are probably missing that piece on the door post, then what are you supposed to do. By doing research and such education occurs and we understand the reasoning behind things, not just take things for face value. That is why if you take your truck and get a "tune up" from a local shop they will tune it back to factory specs and it will probably run like crap. If asked they will say" that is what the factory specs are" and most likely they won't be able to get it to run right. The pressures we run on our tirs are recommended for the softest ride, not for the best wear or mpg.
|
Look at ford and there Explorer problems 10 years ago. And if you think it was Fireston's fault, then you need to do some research. Ford was getting complaints from socker moms that there SUV rode like a truck. (duh) Against Firestone's strong warning on the subject, ford put out the word a few times to keep dropping the pressure, the result was a hot tire that would delmainate and throw it's tread.
My argument normally goes like this;
If your tires aren't OE, same make/model/size/on the same width rim... then that sticker is crap. An exadurated example is my truck... whie granted, there is no sticker, everyone agrees that tire technology is light years ahead of what it was back then. Well, it has increased a whole lot just in 10 years, you just don't know about it. Does anyone want to argue that a tire ment to have 80 PSI will work better at 32 PSI becouse the truck that's bolted to it?
My observations have noticed, that if the tire is the right width for the rim, then max press usually ends up with good temerature across the tread, and best possible MPG. Tread wear is kept even like this too.
I got this info when i was in highschool, I had to do a report (I went to tech school, so the report had to be tech related) This was worth 3/4 of our final grade, so I went all out. I was in contact with the upper level R&D guys at good year, BF-G, and Michilin. I asked them about my temperature idea, which I saw pit crews in both nascar and F-1 checking the tire temp acros the width right after the tires went over the wall after putting new ones on. They all agreed that this is the absoulte best way, hands down, no question asked.
The ONLY exception to this rule, is the corvair.
Quote:
Originally Posted by sdkid
No offence. Like I said, just what i was told. I was getting more at the max pressure spec on the tire. I've never heard of lhm's method for auto tires. I do however use a similar method to adjust the rubber tracks on caterpillar rubber track tractors.
|
It's actually a race track thing, but it makes perfect sence. You want an even temp acros the thread, that way, you KNOW the whole trear is supporting the weight of the vehicle and not getting heated too much.
Quote:
Originally Posted by racin69z
Every situation is different. The 80 psi tires are probably 10 ply 1 ton tires. When I had 35 12.50's on a 10" rim, I had to run 20 psi in the back (not loaded of coarse) to keep it from wearing the center of the tread out. I followed the truck down the road one day with 35 psi in the tires, and you could see air on the outer 3" of tread on both sides.
|
those tires were most likely too big (wide) for the rim.