Air pressure on Montana Tires

[ken]

I know a lot of discussion has been done on the different tires and wheels that Montana uses on their 5th wheels. First of all, I had the standard wheels on our 2003 Montana with the marathon tires. The tires were my problems on that coach blowing out two of them. Now with a 2005 Montana with the fancy alumnumun wheels and Tyco tires, I cannot keep the air pressure at 80 lbs as required. Just sitting for a couple of days, the tires will be down some 6-8 lbs. Now sitting for a couple of months in cold and warm weather, one tire was down to 45 lbs and the others were at 60 lbs. There is no loss of air from punctures or thru the valve stems. That has been checked. I guess I am asking everyone if this is normal or should I look for a fix. I know that alumunum rims do loose more air than steel rims just setting for long times. Some of the fixes I have considered were adding a tube in the tires, or just replacing the tires. So far the tires show no fatique and were manufactured in 2004. Help guys.. I am tired of inflating the tires each time I move the Montana.

[LonnieB]

Ken, were the tires and wheels removed and put under water to check for leaks? They may be leaking around the beads. On some tires there are some very tiny holes in the sidewalls close to the bead, that are part of the mfg. process. I have seen these leak also. If these holes are leaking, the tire mfgr. should warranty them. I would use tubes only as a last resort.

[Glenn and Lorraine]

What Lonnie said and..
Also check the area where the valve stem is inserted into the wheel.

Use a mixture of 2 tablespoons dish washing liquid to 16 oz of water. Spray it on liberally and watch for bubbling. Although tiny, even the slowest leak will eventually blow bubbles.

[ggranch]

At the slow rate you are loosing pressure, soap bubbles may not reveal the leak(s). If all of your tires are leaking approximately the same rate, I would suspect the wheels, possibly in the area of the valve stem seats. Aluminim wheels haveing leaks there is a fairly common thing. Real tire men will cringe at this but us old farmers use and swear by Slime. It is not cheap to set up 4 tires but the results are well worth it.

[Glenn and Lorraine]

quote:Originally posted by ggranch

At the slow rate you are loosing pressure, soap bubbles may not reveal the leak(s). If all of your tires are leaking approximately the same rate, I would suspect the wheels, possibly in the area of the valve stem seats. Aluminim wheels haveing leaks there is a fairly common thing. Real tire men will cringe at this but us old farmers use and swear by Slime. It is not cheap to set up 4 tires but the results are well worth it.

Well ggranch you could be right as I am only basing my tip on many, many years in the tire business as a tire service tech, a tire service manager, general manager and co-owner of a retail/wholesale tire shop. In all those years I probably repaired a few hundred thousand tires. Many with ultra slow leaks and that old dish washing trick worked 99.9% of the time. But, Now that I think about I could be wrong about the dish washing liquid.....NOT.

[texdeano]

Having also spent a few years in the tire bussiness also I would prefer a bath over anything else I have ever used to find a slow leak and I sure would not put tubes in the tires as it will build too much heat and can cause failures.

[LonnieB]

ggranch,
Please don't take offense to what I am about to say, none is intended.
The " slime " is a good thing, but has it's place. In order for the stuff to be effective on a valve stem, or bead leak in a tire of this size, you would have to put about a gallon and a half in each tire. The centrifugal force of that much weight at 65 or 70 mph would do more harm than good. This stuff was designed and engineered for low speed tires, 45 mph or less. I use it in my 4 wheelers & lawn tractor, and I sell it for $2.00 per 1/2 pint. The cost alone is enough to make me say NO to a gallon and a half per tire.

On Edit - BTW, I am a real " tire guy ", and I spent the first 20 years of my working career as the maintenance manager in charge of all the rolling stock on 3 feedlots, and a 20,320 acre farm. Maybe this makes me an " old farmer " too?

[noneck]

We would drown em'...not whole tire and I think Lonnie has said this in other responses to concerns over leaks. Get a deep tub of water, pull tire and sink it in vertically if tire is not big enough to drown the whole thing. Clear water and look for bubbles...works everytime...a little crayon to mark the leak while submerged...I'd also pull the valve cap too just to be sure the scharder valve is not leaking and your good to go!
Chuck

[ols1932]

I'd follow Lonnie and Glenn's advice. When pressurizing, inflate the tires to what the manufacturer calls for.

Orv

[Leaseit]

Ken, as i rememeber you have tire pressrue monitors installed on the valve stems. Since they keep the schrader valves open all the time to monitor the pressure, might it be that the leak is around the valve stem threads where the monitor screws onto the stem.

[sreigle]

Ken, it's not normal. We have the aluminum wheels. Last week I checked the tires. They'd sat in one place for over two months and had dropped from 80 psi to 73. However, I attribute most of that change to the fact that the ambient temperature is 50 degrees cooler than it was when the tires were at 80. Sounds to me like either a leak around the bead or in the rims themselves. I agree with those suggesting the water test.

[rickety]

ould it be the rims themselves? I built a 36 Chev convertible with aluminum wheels and couldn't keep the tires innflated on two of the wheels. Replaced the tires and no luck, one of the tire guys clamped a seal around the ri itself, not a tire and ran it to aobut 85 lbs and let it set in a tank of water for and hour we found fourteen little tiny pin holes in the 2 aluminum wheel castings, and these were American Racing Wheels! Just a thought

[Glenn and Lorraine]

Nothing is impossible. It could very possibly be the wheels. Can't rule out anything until the leak(s) is found.

[ken]

Thanks guys. I went out and checked the tires with Glenns tried and proven method. Yup, you were right. I am loosing air around the rim. I saw bubbles at two points directly across from each other. Since I don't want to move the trailer right now in the winter, I will wait and have them pulled and reseated in Florida in January. I would have to tow the Montana some 40 miles to find a truck tire place to do anything about the problem. I have my trusty air compressor. And traveling I don't loose any air pressure, only when setting for a long period. And thats only on one tire. The rest only loose a couple of pounds. Again, thanks to everyone. See you in Tampa and Branson...........

[Glenn and Lorraine]

That's great. Glad I could be of assistance. See ya in Fla.

[LonnieB]

Hello Ken,
Glad to hear you found the problem. Yes, Glenn's method is tried and true. I don't use it very often, as I have a tank with with a hydraulic mechanism I built to submerge the tires. Sometimes this method doesn't work either, I have found a few that only leak when they have weight on them, usuall a cracked aluminum wheel.

[Cat320]

quote:Originally posted by sreigle

Ken, it's not normal. We have the aluminum wheels. Last week I checked the tires. They'd sat in one place for over two months and had dropped from 80 psi to 73. However, I attribute most of that change to the fact that the ambient temperature is 50 degrees cooler than it was when the tires were at 80. Sounds to me like either a leak around the bead or in the rims themselves. I agree with those suggesting the water test.

Steve...I don't doubt that you have lost some pressure from sitting, but not from a temperature change...as it gets colder, the pressure goes up, not down. Air expands when heated and contracts when cooled...at least that's what it does in airplane tires!

[William H. Collier]

CAT320, you must not ever watch NASCAR, you have it backwords, heat will increase the pressure, cold will decrease it.
Bill

[ols1932]

[quote]quote:Originally posted by Cat320

Steve...I don't doubt that you have lost some pressure from sitting, but not from a temperature change...as it gets colder, the pressure goes up, not down.

Oops! You've got it wrong. Pressure goes up in the tires when they heat up. When they sit, they cool down.

Orv

[LonnieB]

I have to agree with Orv and Bill. As tires heat up the air molecules expand creating higher pressure inside the tire.