Good Post Tom!
J.R.
>
> So far many have posted information on the inflation pressures and types of
> tires various netters use on their coaches. It is obvious that the choice of
> tires for the GMC motorhome is a complex issue and it is complicated by the
> fact that most of us think we are experts because we have used tires for so
> many years on our automobiles. However if we take that attitude with the GMC
> we are going to get into trouble fast. You cannot compare car tires to ones
> used for an RV and especially not the GMC. The GMCmotorhome uses TRUCK TIRES.
>
> I am a perfect example of the ignorance that surrounded this issue, before
> this forum and our discussions. I bought a 1976 palmbeach March 1998, tires
> looked good(Michelins), much bigger and heavier than my car tires, they were
> the proper tires for the vehicle (glovebox sticker told me that)and fat dumb
> and happy I started to drive it. I told myself that the tires could be
> changed later during the winter.
>
> After several thousand miles of driving, first tire went and than a
> catastrophic failure on the second causing over a $1000 damage to the coach
> (generator door, skirt, air bag and paint). Thats when I started looking for
> information. If you have never had a really bad blow out you haven't lived.
> It sounded like a bomb going off in the rear of the coach, complete with
> fire and smoke. Fire later determined to be from the steel belts hitting on
> the bogie suspension and producing lots of sparks. wonder what that would
> have been like on the propane tank side if the tank had been turned on and
> additionally had a leak? Maybe break the LSR?
>
> Some things I found out:
>
> 1. Auto tires have a RECOMMENDED and MAXIMUM cold pressure rating, and
> TRUCK TIRES have a MINIMUM cold pressure rating to carry MAXIMUM loads. Big
> difference, and very critical. If you mix up these two concepts you are
> asking for trouble.
>
> 2. On radial truck tires(ours for the GMC motorhome) the number of plies
> has no meaning! Load range and inflation pressure are the determining
> factors. In other words the GMC needs E rated tires but if you inflate them
> incorrectly you only have a D range or less tire.
>
> 3. A load range E tire is only a load range E tire if it is inflated to the
> correct pressure for the load. And that is critical also. Truck tires
> typically are inflated to carry the present load and this can vary day to
> day in commercial operations by knowedgable people.
>
> 4. GMC rims need Schrader TR570 metal stems and metal sealing caps to hold
> the correct pressure long term. Alcoa rims come with them mounted.
>
> 5. During separate East and West coast GMC motorhome rallys some time ago,
> 86% of the motorhomes tested had underinflated tires and could not carry the
> measured weight safely. At those same rallys 61% of the coaches were
> exceeding their gross vehicle weight. I will make a bet with all of you. If
> you check your pressures right now ( many of you can't since your hubcaps
> are in the way and you have to remove them to check), at least one and
> probably all of your pressures are incorrect for the tires.
>
> 6. Highest tire loading appears to be on the right front tire and can reach
> 3000# if the air suspension is malfunctioning or as some have said they
> dirve in hold! That greatly exceeds the load carrying capacity of all D
> rated tires.
>
> 7. In the case of the GMC motorhome, the tires load is constantly changing
> because of the independent front and rear suspension. If you don't want to
> exceed the recommended tire loads, than the system must be working properly.
>
> I am still learning and as I find out more will post.
>
> Anyone find out anymore facts?
>
> >In a message dated 5/14/99 9:07:19 PM Central Daylight Time,
> >
> >>
> >> My coach came with load range "E" Goodyear G159 which I maintain at
> >> 65 lbs front and rear. I do that because the previous owner said that was
> >> what he did and he had the coach for 18 years.
> >
> >The previous owner of my coach installed "D" load rated 2 + 2 ply Kelly
> >radial tires with 30 PSI mounted on non-radial wheels. He's the same one who
> >insured me they were all radial wheels, the one who installed the 16 ga wire
> >toting 6 volts to the HEI, and the one who didn't know the water pipe going
> >to the commode had burst from freezing 2 years earlier........Ad Nauseum
> >Infinitum.
> >He's the reason I'm going to "E"'s and 65 PSI, and Scott Shean is the
> >reason I have radial wheels to put them on.
> >(and LSU taking out KY is the reason my Diamond Dawgs are going to the SEC
> >tournament next week, 'cause MSU let Ole Miss get away last night - ain't
> >won but 1Friday game all year)
> >
> >Lanier
> >
> >
> Tom & Marg Warner
> Vernon Center NY
> 1976 palmbeach
> "The beautiful Mohawk Vally"
J.R.
>
> So far many have posted information on the inflation pressures and types of
> tires various netters use on their coaches. It is obvious that the choice of
> tires for the GMC motorhome is a complex issue and it is complicated by the
> fact that most of us think we are experts because we have used tires for so
> many years on our automobiles. However if we take that attitude with the GMC
> we are going to get into trouble fast. You cannot compare car tires to ones
> used for an RV and especially not the GMC. The GMCmotorhome uses TRUCK TIRES.
>
> I am a perfect example of the ignorance that surrounded this issue, before
> this forum and our discussions. I bought a 1976 palmbeach March 1998, tires
> looked good(Michelins), much bigger and heavier than my car tires, they were
> the proper tires for the vehicle (glovebox sticker told me that)and fat dumb
> and happy I started to drive it. I told myself that the tires could be
> changed later during the winter.
>
> After several thousand miles of driving, first tire went and than a
> catastrophic failure on the second causing over a $1000 damage to the coach
> (generator door, skirt, air bag and paint). Thats when I started looking for
> information. If you have never had a really bad blow out you haven't lived.
> It sounded like a bomb going off in the rear of the coach, complete with
> fire and smoke. Fire later determined to be from the steel belts hitting on
> the bogie suspension and producing lots of sparks. wonder what that would
> have been like on the propane tank side if the tank had been turned on and
> additionally had a leak? Maybe break the LSR?
>
> Some things I found out:
>
> 1. Auto tires have a RECOMMENDED and MAXIMUM cold pressure rating, and
> TRUCK TIRES have a MINIMUM cold pressure rating to carry MAXIMUM loads. Big
> difference, and very critical. If you mix up these two concepts you are
> asking for trouble.
>
> 2. On radial truck tires(ours for the GMC motorhome) the number of plies
> has no meaning! Load range and inflation pressure are the determining
> factors. In other words the GMC needs E rated tires but if you inflate them
> incorrectly you only have a D range or less tire.
>
> 3. A load range E tire is only a load range E tire if it is inflated to the
> correct pressure for the load. And that is critical also. Truck tires
> typically are inflated to carry the present load and this can vary day to
> day in commercial operations by knowedgable people.
>
> 4. GMC rims need Schrader TR570 metal stems and metal sealing caps to hold
> the correct pressure long term. Alcoa rims come with them mounted.
>
> 5. During separate East and West coast GMC motorhome rallys some time ago,
> 86% of the motorhomes tested had underinflated tires and could not carry the
> measured weight safely. At those same rallys 61% of the coaches were
> exceeding their gross vehicle weight. I will make a bet with all of you. If
> you check your pressures right now ( many of you can't since your hubcaps
> are in the way and you have to remove them to check), at least one and
> probably all of your pressures are incorrect for the tires.
>
> 6. Highest tire loading appears to be on the right front tire and can reach
> 3000# if the air suspension is malfunctioning or as some have said they
> dirve in hold! That greatly exceeds the load carrying capacity of all D
> rated tires.
>
> 7. In the case of the GMC motorhome, the tires load is constantly changing
> because of the independent front and rear suspension. If you don't want to
> exceed the recommended tire loads, than the system must be working properly.
>
> I am still learning and as I find out more will post.
>
> Anyone find out anymore facts?
>
> >In a message dated 5/14/99 9:07:19 PM Central Daylight Time,
> >
> >>
> >> My coach came with load range "E" Goodyear G159 which I maintain at
> >> 65 lbs front and rear. I do that because the previous owner said that was
> >> what he did and he had the coach for 18 years.
> >
> >The previous owner of my coach installed "D" load rated 2 + 2 ply Kelly
> >radial tires with 30 PSI mounted on non-radial wheels. He's the same one who
> >insured me they were all radial wheels, the one who installed the 16 ga wire
> >toting 6 volts to the HEI, and the one who didn't know the water pipe going
> >to the commode had burst from freezing 2 years earlier........Ad Nauseum
> >Infinitum.
> >He's the reason I'm going to "E"'s and 65 PSI, and Scott Shean is the
> >reason I have radial wheels to put them on.
> >(and LSU taking out KY is the reason my Diamond Dawgs are going to the SEC
> >tournament next week, 'cause MSU let Ole Miss get away last night - ain't
> >won but 1Friday game all year)
> >
> >Lanier
> >
> >
> Tom & Marg Warner
> Vernon Center NY
> 1976 palmbeach
> "The beautiful Mohawk Vally"
atrick
