[Archived]

Paul,

You really need to get each axle’s weight. The 110 PSI you currently using is high, but that is far better than being too low.

The correct pressure based on your weights (I have always added 5 PSI) is the ideal weight and I suspect you will be in the 80 to 90 PSI range on your tag and drive axles providing a little better ride.

[Archived]

Paul,

You’ll find the tag is somewhere around 8K lbs. Also, take a look at your front axle weight on the placard and see how close you are to the limit.

[Archived]

Keeping in mind that Michelin’s pressure chart is for minimum pressures. So, you are always better to err on the higher pressure as long as you don’t exceed the maximum pressure stated on the sidewall when the tire is cold. I run 115 on the front and 100 on drives and tags. Yes, my pressures are as much as 15PSI above the minimum recommendations which only means I may be sacraficing ride comfort. When it comes to tire pressures, I put safety above comfort.

If you really want to know what the minimum pressure should be you need to read each wheel position when the coach is fully loaded as you would load it. Use the heaviest wheel position weight per axle to set the minimum for both left and right wheel positions.

Try for a local moving company. Many have scales that can be used to weigh each side. If not, see if you can get your local motor carrier law enforcement guys to do it.

[Corey]

Can you cite your reference Gil?

The tire pressures have been described as providing the ability to carry the load, but also to provide the best road contact for handling and braking. Lower pressures (apart from ruining a tire) subject the contact surface to be at the outer edges of the tread and higher pressures shift the contact surface to be more towards the center of the tread.

The correct pressures are intended to provide the greatest contact surface.

Otherwise Michelin should just say to pump them up to 115.

[Archived]

Thanks to all for the tips on this one. I did check my steer axle rating and it is 17,200. So, at 16,540 now, I guess would not want to kill an elk and strap it to the front…I usually have those shipped home anyway.

I lowered the tire pressue on the rear to just over 95 versus the 110 I was running. I’m anxious to see if I can feel the difference. That pressure still gives me 10 pounds+ of cushion over the recommended pressure.

When I need tires next, I am definatley going to make the change to 365s.

Paul

[Archived]

Paul if you need to save weight the easiest thing would be to just leave the kids at the curb but Keep the dog. They housebreak so much easier.

[Archived]

Red, that is a good tip. We’re pretty lucky though, we’ve got good teenagers…as teenagers go. The dog is not an option. She’s definatley man’s best friend. I love my wife and would not take $10 million bucks for her. BUT, in all the years I’ve had the dog, not once has the dog written a check, she’s never charged anything, never asked to remodel her dog house, and actually gets excited when I tell her we’re going hunting. On the other hand, my wife has never chewed up all the porch cushions. I really can’t live without either one of them or the kids.

Lots of Laughs…Paul

[Larry]

Jon,

Go the Michelin RV tire web site and look at the RV tire guide. Sorry, can’t get the link to post. That describes situations were a tire may be over inflated for the weight carried due to the weight being carried by the tire on the opposite side of the axle. They say they have seen this to be as much as 1,200 pounds. So, over inflation is not only allowed, it may be required. Of course they never say to exceed the cold temperature pressure.

This same guide describes wear problems. It describes under inflation problems. It does not describe nor mention over inflation problems.

These tires aren’t like car tires whereby the contact surface is not significantly affected by tire pressure. From observation you will see that inflation affects the sidewall “crush” far more than tread contact.

Bill Jensen also emphasized that Michelin’s pressures are minimums during a seminar at Prevost Nashville.

Do you have a reference otherwise?

[Roy]

OH ALRIGHT if ya hafta keep them but Im tellin ya when you have to leave the tools at home to save weight you might wanna rethink this LOL. Sounds like you’re a lucky man. Best of luck you all.

[Greg]

I run.. 105 steer

95 drive

85 tag

365’s on steer and tag, with Centramatics …… it’s smoooooth.

[Jerry]

Paul,

The 365’s make a huge difference. I run 105 front, 95 drives and 85 on the tags. I weigh side to side and use the Michelin chart and add 5 lbs.

Gil – If I asked the GSP to weigh they would look at me like I have two heads. Must be better in FL.

[Archived]

Gil,

Your interpretation is skewed a little. Michelin is concerned about variations side to side as a reason to inflate to the higher of the two pressures based on side to side weights, but nowhere in the reference you cited did they say to over inflate. In fact they say:

When one axle end weighs more than the other, use the heaviest of the two end weights to determine the unique tire pressure for all tires on the axle. The maximum cold air pressure for each axle may vary, depending on their weights.

[Archived]

Jon,

I don’t make this stuff up. Read the first paragraph on page 6. It does, in fact, say to “over inflate”.

I recall Michelin’s minimum acceptable pressure for a 315 to be 85 psi regardless of weight carried. For that reason, I would never run 85 psi as any lose of pressure is below Michelin’s recommendation.

I’ve had tires changed at high volume truck tire centers 4 times. Each time I had to tell them what inflate them to. In each case they inflated them to the pressure stated on the sidewall. In each case they stated you can’t hurt them running at their sidewall rated pressure.

[Archived]

I’m afraid I’m with Jon on this one. My experience has been most easily evidenced on my 455/55×22.5 super singles. Inflation to maximum cold pressure, which was in excess of recommended pressure for load, resulted in measurable center wear. I don’t have definitive evidence on the other sizes.

[Archived]

Joel, I’m with you. If I had excessive center wear I would reduce my pressure. My tags are over inflated the most at 15 psi over minimum recommendation. I have 25K miles on my current tires and none of my tires have uneven thread wear.