Yesterday was beautiful in New York so wife and I thought that we would take
the 76 palmbeach into the Adirondacks for the day, eat and relax with a good
book. The coach had not been driven since july when we had gone to the last
GMC Heritage cruiser rally. The drivers side front tire was slighlty down so
gave it a shot of air, hit the starter and the olds roared to life and
within minutes returned to idle sounding like only an olds 455 can sound.
Hit the road and immediately noticed a vibration that I had not noticed
before. I atributed it to sitting since July and kept going, or maybe the
strong side winds that were blowing. Ten miles later the vibration was
getting worse so pulled off the road to check the tires etc. thought that
maybe I had left lug nuts loose while working on it or something similar.
everything seemed alright and all tires looked fine. On the road again
travelled another 10 miles and the vibration only got worse. Pulled off the
road again and rechecked everything. This time found that the middle
drivers side Michelin was starting to separate in the middle of the tire,
tear in the circumferance of the tire about 10-12 inches long. Turned around
and headed for home and the garage to replace it, driving slow. Changed the
tire and within 30 minutes back on the road again.
Spent a wonderful afternoon and returned home late in the afternoon, the
coach ran beautiful in the mountains, very smooth and lots of power.
1/4 mile from home, violent explosion in the drivers rear, coach was still
under control and everything went fine as I pulled off the road to see what
had happened. Thought that I had lost the Onan generator the noise and
force was so strong. To my amazement, the rear drivers side tire had blown
entirely apart with a large cut almost from sidewall to sidewall and another
long gash about 16 inches the circumferance of the tread. When the tire
exploded it tore the fittings off the air bag which immediately deflated,
tore a small piece off the bottom of the generator door, and ruined the
center skirt.
I guess I was neglectful in not noticing that the tires were D rated Michlin
tires on my coach, something that has been talked about lots on this net,
and something that I am firmly against using on the GMC motorhome. I had
been so intent on fixing the mechanical problems that I had neglected one of
the most important ones the tires!
I had checked them all and they lookded fine with lots of tread and no age
cracks.
I had already decided to replace all of the tires with goodyear G-159s
225/75R-16s and Alcoa wheels when rebuilding the coach this winter.
I AM ABSOLUTELY CONVINCED THAT D RATED TIRES AND TIRES LARGER THAN EITHER
8.75-16.5 OR 225/75R SHOULD NOT BE USED ON THE GMC MOTORHOME. If you do not
use E rated tires and the original diameter tires you are courting a
catastrophe, plain and simple. The D rated tires in bias rated tires simply
will not withstand the high sidewall stresses the GMC produces. Why not the
larger tires? Because when they deflate at speed they will do a lot of
damage to the coach, not enough clearance for them when the air bags are
deflated. I have a Cinnabar bulletin that says the coach should not be moved
when a bag is deflated and the tires are oversize.
Remember that GMC recalled all of the D rated tires and replaced them early
on in the first coaches because of the many failures.
Bottom line. I have read with amazement that some of you are putting D rated
bias ply tires on your coaches and I think you are making a big mistake. It
is dangerous. You may get away with it for a while, but it only takes one
blow out from overstressing the tire to make you a believer. It is not worth
the risk.
the 76 palmbeach into the Adirondacks for the day, eat and relax with a good
book. The coach had not been driven since july when we had gone to the last
GMC Heritage cruiser rally. The drivers side front tire was slighlty down so
gave it a shot of air, hit the starter and the olds roared to life and
within minutes returned to idle sounding like only an olds 455 can sound.
Hit the road and immediately noticed a vibration that I had not noticed
before. I atributed it to sitting since July and kept going, or maybe the
strong side winds that were blowing. Ten miles later the vibration was
getting worse so pulled off the road to check the tires etc. thought that
maybe I had left lug nuts loose while working on it or something similar.
everything seemed alright and all tires looked fine. On the road again
travelled another 10 miles and the vibration only got worse. Pulled off the
road again and rechecked everything. This time found that the middle
drivers side Michelin was starting to separate in the middle of the tire,
tear in the circumferance of the tire about 10-12 inches long. Turned around
and headed for home and the garage to replace it, driving slow. Changed the
tire and within 30 minutes back on the road again.
Spent a wonderful afternoon and returned home late in the afternoon, the
coach ran beautiful in the mountains, very smooth and lots of power.
1/4 mile from home, violent explosion in the drivers rear, coach was still
under control and everything went fine as I pulled off the road to see what
had happened. Thought that I had lost the Onan generator the noise and
force was so strong. To my amazement, the rear drivers side tire had blown
entirely apart with a large cut almost from sidewall to sidewall and another
long gash about 16 inches the circumferance of the tread. When the tire
exploded it tore the fittings off the air bag which immediately deflated,
tore a small piece off the bottom of the generator door, and ruined the
center skirt.
I guess I was neglectful in not noticing that the tires were D rated Michlin
tires on my coach, something that has been talked about lots on this net,
and something that I am firmly against using on the GMC motorhome. I had
been so intent on fixing the mechanical problems that I had neglected one of
the most important ones the tires!
I had checked them all and they lookded fine with lots of tread and no age
cracks.
I had already decided to replace all of the tires with goodyear G-159s
225/75R-16s and Alcoa wheels when rebuilding the coach this winter.
I AM ABSOLUTELY CONVINCED THAT D RATED TIRES AND TIRES LARGER THAN EITHER
8.75-16.5 OR 225/75R SHOULD NOT BE USED ON THE GMC MOTORHOME. If you do not
use E rated tires and the original diameter tires you are courting a
catastrophe, plain and simple. The D rated tires in bias rated tires simply
will not withstand the high sidewall stresses the GMC produces. Why not the
larger tires? Because when they deflate at speed they will do a lot of
damage to the coach, not enough clearance for them when the air bags are
deflated. I have a Cinnabar bulletin that says the coach should not be moved
when a bag is deflated and the tires are oversize.
Remember that GMC recalled all of the D rated tires and replaced them early
on in the first coaches because of the many failures.
Bottom line. I have read with amazement that some of you are putting D rated
bias ply tires on your coaches and I think you are making a big mistake. It
is dangerous. You may get away with it for a while, but it only takes one
blow out from overstressing the tire to make you a believer. It is not worth
the risk.