Tire Pressure.

[micki49]

I have a 2008 38ft Monaco Knight DP I was just wondering what is the lowest and highest tire pressure that anyone has ran on thier rig safely.
Thanks your your answers.

[clyon51]

I wouldn't base my tire pressure on anyone elses. Different tire brand/sizes, rig weights, ect.

I've always start with the max cold pressure. Load the rig as I normally do along with fuel, water, ect. In most cases, the tires will be too hard and you'll hear/feel every joint in the road. Every time I stop, I just let a little out, until such time as I know they are no longer too hard. I note the hot pressure and check the cold the next morning. Once I note the cold pressure, I use that as a baseline to keep them at, cold.

[Chargerman]

Tire pressures should always be set cold and based on the tire manufacturers psi recommendations based on the weight being carried by the specific tire model and size. Best to get a copy of the manufacturers chart and then get the Coach to a scale to determine its weight on each axle. Tires should not be set to a hot setting or by what feels good.

[twinboat]

Originally Posted by clyon51

I wouldn't base my tire pressure on anyone elses. Different tire brand/sizes, rig weights, ect.

I've always start with the max cold pressure. Load the rig as I normally do along with fuel, water, ect. In most cases, the tires will be too hard and you'll hear/feel every joint in the road. Every time I stop, I just let a little out, until such time as I know they are no longer too hard. I note the hot pressure and check the cold the next morning. Once I note the cold pressure, I use that as a baseline to keep them at, cold.

That could be dangerous advce.

You can't just deflate tires until they feel right. That is far to subjective. You could be running underinflated and in danger of a tire failure.

There are minimum pressures for particular weights. They make tire charts and scales for setting tire pressures. If not available, the MH manufacture has tire pressure recommendations. Use them until you get on a scale.

[clyon51]

Originally Posted by twinboat

That could be dangerous advce.

You can't just deflate tires until they feel right. That is far to subjective. You could be running underinflated and in danger of a tire failure.

There are minimum pressures for particular weights. They make tire charts and scales for setting tire pressures. If not available, the MH manufacture has tire pressure recommendations. Use them until you get on a scale.

If you read my post, they are inflated to max cold pressure for the tire. It is then determined (by something on the evolution scale somewhere above an ameba) that the ride is ok or too hard. If too hard, take 2-3 lbs out and go down the road a few hundred miles for further evaluation.

Now, if you are clueless as to how a tire with too much pressure effects the ride (on any vehicle), disregard my post. If you are experienced enough, you already know what I'm saying.

[Woodman018]

Dan, With the cost of a set of tires and the safety of you and your family, I would strongly suggest that you get your coach weighed when fully loaded, ready for a trip. The proper way is to weigh each side of each axle and inflate using your tire manufactures chart. If one front tire has a load of 4500 LB and the other has a load of 5200 LB you should inflate both front tires to the 5200 LB setting stated in your chart, always the same pressure for both sides of the axle. Too much pressure causes the tire to wear in the middle and reduce traction, too little pressure causes the tire to wear toward the outside of the tread, reduce mileage, run hot and possibly blow out prematurely. Record your readings and store in a safe place. Safe travels.

Dave

[micki49]

Thanks for the info.

[vsheetz]

Originally Posted by Woodman018

Dan, With the cost of a set of tires and the safety of you and your family, I would strongly suggest that you get your coach weighed when fully loaded, ready for a trip. The proper way is to weigh each side of each axle and inflate using your tire manufactures chart. If one front tire has a load of 4500 LB and the other has a load of 5200 LB you should inflate both front tires to the 5200 LB setting stated in your chart, always the same pressure for both sides of the axle. Too much pressure causes the tire to wear in the middle and reduce traction, too little pressure causes the tire to wear toward the outside of the tread, reduce mileage, run hot and possibly blow out prematurely. Record your readings and store in a safe place. Safe travels.

Dave

Agree.

[twinboat]

Originally Posted by clyon51

If you read my post, they are inflated to max cold pressure for the tire. It is then determined (by something on the evolution scale somewhere above an ameba) that the ride is ok or too hard. If too hard, take 2-3 lbs out and go down the road a few hundred miles for further evaluation.

Now, if you are clueless as to how a tire with too much pressure effects the ride (on any vehicle), disregard my post. If you are experienced enough, you already know what I'm saying.

Goodyear must be clueless.

IMPORTANT: It's a common practice for RV owners to lower tire pressure in their search for a smoother ride. This is not only dangerous, it's relatively ineffective, as the difference in ride quality is not significant. When minimum inflation pressure requirements are not met, tire durability and optimum operating conditions are compromised. Tire inflation pressure should always meet at least the minimum guidelines for vehicle weight.

http://www.goodyearrvtires.com/tire-...n-loading.aspx

[barmcd]

Tire pressure is determined by the weight of the coach and the design of the tire--manufacturers are very specific when they list tire pressures for different weights in 5 psi increments. Setting pressure by feel is courting disaster in my opinion.

[MTK46]

After weighting my new to me Monaco & checking Bridgestones chart for my tires I found Monaco's tag to be correct. 110 for fronts, 100 for drive & 85 for tag.

[Mr_D]

Originally Posted by clyon51

If you read my post, they are inflated to max cold pressure for the tire. It is then determined (by something on the evolution scale somewhere above an ameba) that the ride is ok or too hard. If too hard, take 2-3 lbs out and go down the road a few hundred miles for further evaluation.

Now, if you are clueless as to how a tire with too much pressure effects the ride (on any vehicle), disregard my post. If you are experienced enough, you already know what I'm saying.

The pressure on the sidewall of a Michelin RV tire and many others is not the "Maximum" cold pressure the tire should ever have (unlike car tires) it is the minimum to support the maximum rated carrying capacity of the tire. NHTSA defines truck tires as those rated for vehicles over 10,000#'s GVWR.

From the Michelin RV Tire Guide:

"If you look at the tire's sidewall, you'll see the maximum load capacity allowed for the size tire and load rating, and the minimum cold air inflation needed to carry the maximum load."

From page 6 of the GoodYear RV Tire and Care Guide:

"How much air is enough?
The proper air inflation for your tires depends on how much your fully loaded RV or trailer weighs. Look at the sidewall of your RV tire and you’ll see the maximum load capacity for the tire size and load rating, as well as the minimum cold air inflation, needed to carry that maximum load."

From TOYO:

Q: What are the consequences of inflating the tires to accommodate the actual loads?
A: If the inflation pressure corresponds to the actual tire load according to the tire manufacturer’s load and pressure table, the tire will be running at 100% of its rated load at that pressure. This practice may not provide sufficient safety margin. Any air pressure loss below the minimum required to carry the load can result in eventual tire failure.

But then they go ahead and publish a weight/pressure chart allowing lower pressure for RV's!!

From the August 2010 Motorhome Magazine "Tread Carefully" tire article:

The maximum load capacity allowed for the size tire and load rating and the minimum cold air inflation needed to carry that maximum load are located on the tire’s sidewall.

From our owners manual:

Federal law requires that the tire’s maximum load rating be molded into the sidewall of the tire.
If you look there, you will see the maximum load allowed and the cold air inflation pressure required to carry that stated maximum load. Less air pressure restricts the tire to carry a lighter load.

[JohnBoyToo]

Thanks Mr D - well said and, as usual, correct !

and everyone's coach is different... different wife's shoe count, different loading front to rear and side to side, different appliances, floor plan, etc...

And to Micki49, the OP...

SEE what you started ?!?!

Now ask about oil brands

but to your question - start out at the sidewall or placard as a COLD psi until you can weigh it at a Cat Scale for $10 or better yet a per wheel weight...

[Robin_M]

Originally Posted by clyon51

If you read my post, they are inflated to max cold pressure for the tire. It is then determined (by something on the evolution scale somewhere above an ameba) that the ride is ok or too hard. If too hard, take 2-3 lbs out and go down the road a few hundred miles for further evaluation.

Now, if you are clueless as to how a tire with too much pressure effects the ride (on any vehicle), disregard my post. If you are experienced enough, you already know what I'm saying.

Hmm... I THINK I have an IQ at least slightly above that of ameba , and having owned a trucking company, I'm not clueless about what you are saying about too much air pressure affecting the ride. But I must admit that I do find it a bit perplexing as to why you would go through that seemingly convoluted and time-consuming procedure when all you really need to do is to refer to the tire manufacturer's inflation chart - so much easier.

Like many folks, I do not have access to a scale where I can get individual tire weights, but anyone can get individual axle weights at just about any public scale. I just divide by two (or by four on the duels) and use that for looking up the proper recommended inflation in the chart. Then I add approx. 10 PSI (give or take) for the front and about 5-7 PSI for the rear. I know that's not precisely the procedure that the experts recommend, but it's very easy to do, and it probably gives you very close to the proper recommended cold air inflation level for safely carrying your loaded vehicle, if not just a tad above. The resulting pressure is usually considerably below the maximum inflation level printed on the tire, while at the same time, offering both a margin of error for safety (around 10%), and a relatively comfortable ride.