The reasons it keeps coming up should be obvious. Some of them in no
particular order:
1. GMC recommended D range at 60 psi, 70 psi at high speed
the suspension and weight is still the same.
2. tires are a compromise between cost, braking, handling, ride,
durability, life. saying one tire is the "one" is ridiculous.
3. There are stronger tires available, G159 G range for example.
3700+ load 110 psi. I have a set on a cattle trailer.
Would you run those? They will fit.
4. The recall you mention was from General Tire, not GMC and from 1981
tires have changed.
If you read between the line it is clear that the problem was not
tires but bad design of the hubcaps. People couldn't check air
pressure easily so they didn't, tires blew, they blamed General Tire.
To paraphrase the recall: CHeck the tire pressures, if
you are not going to do that then put on the strongest tire we
make and fill it to the max. Then you can't blame us when it fails!
5. The tire they insisted you buy is no longer available. They did not
specify
just a size but one particular tire. There is significant variation in
the construction and load carrying ability of different E range tires.
6. The load range is not the most critical part of the equation. As
many people have mentioned it is the age of the tire. New D range tires
are a lot safer than 5 year old E's. Properly inflated of course, if
you don't check your tires it doesn't matter what you run, they are not
safe.
7. Steel is not the best material for tires, it rusts if you get a
puncture in the wrong place, shortening the life of the tire. Again it
is a compromise between cost and performance. Michelin had a problem
with this years ago and did something to the rubber to improve the bond
between rubber and cords. Sorry but I don't remember the details.
8. what certified tests ? Not denying that they exist, just that I have
never seen them so I can't judge. If I don't know about them I can't
take them into account.
9. There is nothing special about the gmc in respect to tire stress.
Tandem axles and front wheel drives are common. So common tire design
rules apply. The occasional talk about dynamic loads is nonsense. All
vehicles have dynamic loads on their tires, tandem axles have less than
singles, not more. They have more side forces but that is only in low
speed sharp turns and is not really important to tire life.
10. Tire design is not a myth.
11. Some people just like to argue.
>
> Chuck trying to put this incessant regurgitation of the myths on the proper
> tires and tire pressures or the GMC motorhome to rest is nothing short of
> frustrating. How many times have we got to go over this before everyone
> understands. IT HAS NOTHING TO DO WITH HOW MUCH WEIGHT IS ON EACH TIRE.
> CERTIFIED TESTS HAVE PROVEN IT SHOULD BE AN LT225/75R16 ALL STEEL TIRE
> INFLATED TO 80PSI.
> The supplied recall sticker from General motors did not say sometimes it
> should, it did not say, chuck has the option, it did not even say that it is
> tom warners opinion. It was very clear.
>
> Why are we still discussing this?Look at the General Motors letter and
> recall sticker and tell me what you dont understand and where you keep
> getting these crazy ideas about tire pressure?
>
> http://www.web-access.net/~bmassey/tire_recall.html
>
> >Michelin books and Goodyear web page agree on tire pressure verses load on
> >these tires. Michelin book recommends measuring the load on each tire
> >individually for a fully loaded RV and then "For control of your RV, it is
> >critical that the tire pressures be the same across an axle". To me, that
> >means measuring the full GMC on each front wheel and both back wheels as a
> >set and determining what the correct pressure should be from the chart on
> >that set of axles. So you should wind up with two different tires pressures,
> >one for the front axial and one for the rear axials.
> >
> >They also recommend a calibrated dual end gage.
> >
> >The cold inflation tire pressures verses the loads for single LT225/75R16:
> >
> >35psi/1500 lbs
> >40psi/1650 lbs
> >45psi/1790 lbs
> >50psi/1940lbs
> >55psi/2060lbs
> >60psi/2190lbs
> >65psi/2335lbs
> >70psi/2440lbs
> >75psi/2560lbs
> >80psi/2680lbs
> >
> >They also recommend increasing the recommended tire pressure by 5 psi "to
> >accommodate temporary shifting of load from side to side which is common in
> >RV's".
> >
> >"A tire that is underinflated will build up excessive heat that may go
> >beyond the prescribed limits of endurance of the rubber and the radial
> >cords. This could result in sudden tire failure. A tire that is
> >underinflated will also cause poor vehicle handling, rapid and/or irregular
> >tire wear, and an increase in rolling resistance which results in a
> >decreased in its fuel economy."
> >
> >"Overinflation will reduce the tire's footprint or contact patch with the
> >road, thus reducing the traction, breaking capacity and handling of the
> >vehicle. A tire that is overinflated for the load that it is carrying will
> >also contribute to a harsh ride, uneven tire wear, and will be more
> >susceptible to impact damage."
> >
> >Lowering tire pressures to match their load on our light 23' was the
> >cheapest and fastest way to cut down on darting in wheel ruts.
> >
> >Year of manufacture is currently the last three numbers of the DOT number
> >system. The first two numbers are the week of the year and the last number
> >is the year. That will be changed in the future to a four number system with
> >the first two numbers being the week of the year and the last two being the
> >year. "In cooler, clean air locations, the expected tire life will be
> >longer than in high temperature, high ozone areas".
> >
> >Hope this information clears the air on what is the correct tire pressure
> >for your GMC. I know mine not only rides better, but is a lot less sensitive
> >to road ruts with the tire pressure lowered to match the tire load + 5 psi.
> >
> >
> >
> >
particular order:
1. GMC recommended D range at 60 psi, 70 psi at high speed
the suspension and weight is still the same.
2. tires are a compromise between cost, braking, handling, ride,
durability, life. saying one tire is the "one" is ridiculous.
3. There are stronger tires available, G159 G range for example.
3700+ load 110 psi. I have a set on a cattle trailer.
Would you run those? They will fit.
4. The recall you mention was from General Tire, not GMC and from 1981
tires have changed.
If you read between the line it is clear that the problem was not
tires but bad design of the hubcaps. People couldn't check air
pressure easily so they didn't, tires blew, they blamed General Tire.
To paraphrase the recall: CHeck the tire pressures, if
you are not going to do that then put on the strongest tire we
make and fill it to the max. Then you can't blame us when it fails!
5. The tire they insisted you buy is no longer available. They did not
specify
just a size but one particular tire. There is significant variation in
the construction and load carrying ability of different E range tires.
6. The load range is not the most critical part of the equation. As
many people have mentioned it is the age of the tire. New D range tires
are a lot safer than 5 year old E's. Properly inflated of course, if
you don't check your tires it doesn't matter what you run, they are not
safe.
7. Steel is not the best material for tires, it rusts if you get a
puncture in the wrong place, shortening the life of the tire. Again it
is a compromise between cost and performance. Michelin had a problem
with this years ago and did something to the rubber to improve the bond
between rubber and cords. Sorry but I don't remember the details.
8. what certified tests ? Not denying that they exist, just that I have
never seen them so I can't judge. If I don't know about them I can't
take them into account.
9. There is nothing special about the gmc in respect to tire stress.
Tandem axles and front wheel drives are common. So common tire design
rules apply. The occasional talk about dynamic loads is nonsense. All
vehicles have dynamic loads on their tires, tandem axles have less than
singles, not more. They have more side forces but that is only in low
speed sharp turns and is not really important to tire life.
10. Tire design is not a myth.
11. Some people just like to argue.
>
> Chuck trying to put this incessant regurgitation of the myths on the proper
> tires and tire pressures or the GMC motorhome to rest is nothing short of
> frustrating. How many times have we got to go over this before everyone
> understands. IT HAS NOTHING TO DO WITH HOW MUCH WEIGHT IS ON EACH TIRE.
> CERTIFIED TESTS HAVE PROVEN IT SHOULD BE AN LT225/75R16 ALL STEEL TIRE
> INFLATED TO 80PSI.
> The supplied recall sticker from General motors did not say sometimes it
> should, it did not say, chuck has the option, it did not even say that it is
> tom warners opinion. It was very clear.
>
> Why are we still discussing this?Look at the General Motors letter and
> recall sticker and tell me what you dont understand and where you keep
> getting these crazy ideas about tire pressure?
>
> http://www.web-access.net/~bmassey/tire_recall.html
>
> >Michelin books and Goodyear web page agree on tire pressure verses load on
> >these tires. Michelin book recommends measuring the load on each tire
> >individually for a fully loaded RV and then "For control of your RV, it is
> >critical that the tire pressures be the same across an axle". To me, that
> >means measuring the full GMC on each front wheel and both back wheels as a
> >set and determining what the correct pressure should be from the chart on
> >that set of axles. So you should wind up with two different tires pressures,
> >one for the front axial and one for the rear axials.
> >
> >They also recommend a calibrated dual end gage.
> >
> >The cold inflation tire pressures verses the loads for single LT225/75R16:
> >
> >35psi/1500 lbs
> >40psi/1650 lbs
> >45psi/1790 lbs
> >50psi/1940lbs
> >55psi/2060lbs
> >60psi/2190lbs
> >65psi/2335lbs
> >70psi/2440lbs
> >75psi/2560lbs
> >80psi/2680lbs
> >
> >They also recommend increasing the recommended tire pressure by 5 psi "to
> >accommodate temporary shifting of load from side to side which is common in
> >RV's".
> >
> >"A tire that is underinflated will build up excessive heat that may go
> >beyond the prescribed limits of endurance of the rubber and the radial
> >cords. This could result in sudden tire failure. A tire that is
> >underinflated will also cause poor vehicle handling, rapid and/or irregular
> >tire wear, and an increase in rolling resistance which results in a
> >decreased in its fuel economy."
> >
> >"Overinflation will reduce the tire's footprint or contact patch with the
> >road, thus reducing the traction, breaking capacity and handling of the
> >vehicle. A tire that is overinflated for the load that it is carrying will
> >also contribute to a harsh ride, uneven tire wear, and will be more
> >susceptible to impact damage."
> >
> >Lowering tire pressures to match their load on our light 23' was the
> >cheapest and fastest way to cut down on darting in wheel ruts.
> >
> >Year of manufacture is currently the last three numbers of the DOT number
> >system. The first two numbers are the week of the year and the last number
> >is the year. That will be changed in the future to a four number system with
> >the first two numbers being the week of the year and the last two being the
> >year. "In cooler, clean air locations, the expected tire life will be
> >longer than in high temperature, high ozone areas".
> >
> >Hope this information clears the air on what is the correct tire pressure
> >for your GMC. I know mine not only rides better, but is a lot less sensitive
> >to road ruts with the tire pressure lowered to match the tire load + 5 psi.
> >
> >
> >
> >
