Recommended Minimum Tire Pressure

carolinagirl · 12-22-2013, 06:27 AM

2014 Winnebago Adventurer 37F

I went to the Michelin site, but only found the max tire pressure. We have 255 80R 22.5 XRV

Clearly it says 110 Max on both dual and single on the tire itself.

GAWR on the Winnebago yellow sticker is 100 PSI so already I have 10 PSI difference.

We have not weighed, just got it and locally no scales. I installed the Truck Technologies Tire minder and I am trying to put the information into the program for min/max

Any suggestions ya'll can offer?

thanks!

Selah · 12-22-2013, 07:48 AM

I believe that the minimum tire pressure is around 75 PSI no matter how light the loading is. I would NOT run that low until you can get some weights. Post Pilot stations have CAT scales.
Until you can get some weights I would recommend using the max tire pressure listed on the sidewall. As for setting your minimum and maximum alarms on your TPMS it is not unusual for tires to gain 15-20 PSI while driving. I set my minimums at 10 PSI below my target pressure.

CHCam42 · 12-22-2013, 08:09 AM

235/80R22.5 LRG XRV®, XZE®
PSI 70 75 80 85 90 95 100 105 110 Maximum load & pressure on sidewall
kPa 480 520 550 590 620 660 690 720 760
LBS Single 3470 3645 3860 3975 4140 4300 4455 4610 4675 S 4675 LBS at 110 PSI
Dual 6320 6630 7050 7230 7530 7940 8110 8390 8820 D 4410 LBS at 110 PSI
KG Single 1570 1650 1750 1800 1880 1950 2020 2090 2120 S 2120 KG at 760 kPa
Dual 2860 3000 3200 3280 3420 3600 3680 3800 4000 D 2000 KG at 760 kPa

This is from their web site. 70 psi is minimum. Look next to the drivers seat and you will find a chart with axel, GCWR and tire pressures. Use these until you weigh coach. All flyin J fuel stations have scales. Go inside and tell them you wan to weigh coach and they will explain how to do it.
Good luck and enjoy the new adventure.
Clark

http://www.michelinrvtires.com/miche...ion-tables.jsp

Dr4Film · 12-22-2013, 08:13 AM

Until the coach is weighed on ALL four corners, then the minimum tire pressure is the MAXIMUM stamped on either the wheel or the side of the tire. One may be less than the other and that's the one you use.

Dr4Film ----- Richard

carolinagirl · 12-22-2013, 08:30 AM

Thanks Ya'll, I do not know if the TMS was programmed at the dealer or not. but I am getting an alarm on driver right at 97 and back driver inside 98 The rest at 100,102,101

My husband says eh does not think 2 pounds is a big deal.....

Do I need to make them all 110?

thanks!

carolinagirl · 12-22-2013, 08:32 AM

Thanks! So maybe I should reprogram to be 108 for all tires max and 90 for the minimum?

dengraham · 12-22-2013, 08:42 AM

Selah is correct. The minimum has nothing to do with the rating on the tire. It has to do with when the TPMS will sound an alarm to indicate your tire pressure is getting to low. They used to recommend no more than 10% of your target but some people feel if the tire is 5 lbs lower than their target, then they want to know about it.
After you obtain your weights (IN THEORY) the recommended tire pressure could be at the very minimum pressure. I have only seen this once on a tag axle that was not adjusted properly. So, let us say it is 75 lbs. Then, maybe you want to know if the tire has lost pressure to 70, or 71, or 73, or even 74??
For the tire company the minimum is the lowest pressure they have tested the tire. It does not mean the tire cannot handle it; it just means the tire company has not tested it. Many people (including the Gaffney Service Center) recommend whatever the recommended tire pressure from the tire company that you add 5 lbs just to provide a little harder tire to decrease heat in the tire or in case you increase the weight on the axle. It results in a little harder ride but not really noticeable. Please remember running the tires at their maximum pressure is typically too hard. The decal in the motorhome is based on a maximum load for the chassis. But, your real target pressure is not known unless you weigh all four corners.

Dr4Film · 12-22-2013, 08:47 AM

Sorry, I did not read you entire first post. I now realize that you are trying to program limits in your TPMS device.

To do that, you first need to know what your base PSI's should be for each tire/axle. That is called your CIP or Cold Inflation Pressure. It is determined by the weight of each corner of your coach and then looking up the PSI/WEIGHT chart for your specific brand and model of tire you have on the coach.

You ALWAYS use the same pressure for each side of the axle but set the PSI for the HIGHEST weight on that axle.

The tire should be inflated to your CIP early in the morning before the sun is on the tire, that's why they call it Cold Inflation Pressure.

Your TPMS device can then be for HIGH and LOW limits if that's what is needed.

Remember that it is standard in the industry that if a tire gets to 25% low in PSI from BASE CIP, it is considered FLAT. However, you never want to wait that long. Damage to your tire has already happened by then. You will want an ALERT at about the 12.5% level.

Dr4Film ----- Richard

UFO Pilot · 12-22-2013, 11:20 PM

After weighing my Coach, the tire charts show my pressures should be 90, I run 95 and my TPMS is set for a low of 85.

Tireman9 · 12-24-2013, 01:17 PM

Two separate issues.
Answers have been provided re the minimum pressure to set the tires to the morning of every travel day. Until you know the actual load on each tire you should run no less than the inflation shown on the Placard.

I think the TireMinder warns of low pressure at 15% loss.
I would not be as concerned with the high pressure warning which I think TireMinder is set to 25% above the cold inflation setting.
I think the TPMS has a high temperature warning at about 167F which is more likely to indicate a problem than high pressure.

The TireTraker TPMS has a rapid air loss warning when you loose 3psi in 2 minutes and similar when you loose 6 psi in 2 to 10 minutes. TireMindere may have similar settings. You might want to review the manual for TireMinder.

Until you get the individual tire loads I suggest you at least get individual axle weights to ensure you have at least a 10% safety factor (are under the GAWR)

carolinagirl · 12-25-2013, 05:33 AM

So glad I joined this forum! I am learning so much! I appreciate all the answers! I got the TMS done and feel alot better about tires now! That is for sure something i knew nothing about! Thank you for the education!

bachler · 12-25-2013, 12:30 PM

We blew out 2 2.75 X 22.5 On our Ultimate. Side wall . I was using some persons Rating of 75 Lbs .. I wised up and followed the manufactures Max. pressure and dropped it To 100lbs (110lb Rec.Max.) ALL the way around it rides a little rougher. BUT I knock 10 MPG on the 330 Cat Running at 60 MPH.. I get an upset tommey When I hear of Owners Dropping a tire to Much less then the Man. max.. You do NOT want the side walls to flex. If they do they get hot And WILL. BLOWOUT.. Then we can blame the tire co. for our stupidity.. I know I did it... Life is good.

Tireman9 · 12-25-2013, 08:45 PM

Quote:

Originally Posted by bachler

We blew out 2 2.75 X 22.5 On our Ultimate. Side wall . I was using some persons Rating of 75 Lbs .. I wised up and followed the manufactures Max. pressure and dropped it To 100lbs (110lb Rec.Max.) ALL the way around it rides a little rougher. BUT I knock 10 MPG on the 330 Cat Running at 60 MPH.. I get an upset tommey When I hear of Owners Dropping a tire to Much less then the Man. max.. You do NOT want the side walls to flex. If they do they get hot And WILL. BLOWOUT.. Then we can blame the tire co. for our stupidity.. I know I did it... Life is good.

Sidewall "blowouts" on steel body radials are the result of running significantly under-inflated and I don't mean 10% or20%.

I have no idea why you would use "some persons rating of 75psi" when your vehicle spec sheet (placard) specified higher.

bachler · 12-28-2013, 01:38 PM

It needs to be pointed out ,That when a tire gets warm.( For a sinrieo only) If a tire/rubber gets warm.and cools (100/125 deg) off the rubber gets LESS flexable And eventulay it will come un glued/Volconized From the thread/tire structure. The right thing happens. It will Blow out;. We in out testing have dropped tire pressure. For that nice cussie ride and Much less MPG . verces High pressure The high pressure allways wins. Then someone smart says Well I pump mine up 20lbs over Reccomended, I still say Stupidty can be fixed. Life is good. Within reason;;

Tireman9 · 12-28-2013, 03:49 PM

Quote:

Originally Posted by bachler

It needs to be pointed out ,That when a tire gets warm.( For a sinrieo only) If a tire/rubber gets warm.and cools (100/125 deg) off the rubber gets LESS flexable And eventulay it will come un glued/Volconized From the thread/tire structure. The right thing happens. It will Blow out;. We in out testing have dropped tire pressure. For that nice cussie ride and Much less MPG . verces High pressure The high pressure allways wins. Then someone smart says Well I pump mine up 20lbs over Reccomended, I still say Stupidty can be fixed. Life is good. Within reason;;

Sorry, I think you do a dis-service with such sarcastic comments that some might think were based on facts.
There is simply no reason for properly loaded & inflated tires to simply fail in mid sidewall. This is the coolest part of the tire which means it suffers the least degradation. There is also no part of the tire manufacturing process that would leave contaminant in the nice circumferential band around the tire.
Sorry but sidewall "blowouts" are just flex failures from running significantly under-inflated.

Pusherman · 12-28-2013, 03:56 PM

Tireman9 has provided excellent information on this thread regarding tire inflation information. Thanks for good and trustworthy info!

Dr4Film · 12-28-2013, 05:50 PM

Quote:

Originally Posted by Pusherman

Tireman9 has provided excellent information on this thread regarding tire inflation information. Thanks for good and trustworthy info!

X2

Before a tire will de-vulcanize the temperature of the tire has to be well over 200F. If I remember correctly it's about 280F - 290F. This article states that anything over 250F and you have to start worrying about vulcanization.

http://www.bridgestonetrucktires.com...canization.asp

Dr4Film ----- Richard

adventurous2 · 12-28-2013, 08:12 PM

We just found our motorhome in our parking lot with one tire completely empty, sitting on the rim.(front right) The left front tire only had 30 pounds in it. We do not know how long the motorhome has been sitting like this.(not more then 10 days). With the Good Sam help both tires have been inflated back to 95 pounds. There seemed to have had faulty/leaky stems. new ones have been installed.
QUESTION... Is the right tire completely shot or is is stil safe to drive on it? We just got a TPM system and can keep an eye on the tires. All tires on our rig are about 5 years old.

Tireman9 · 12-28-2013, 08:38 PM

Quote:

Originally Posted by adventurous2

We just found our motorhome in our parking lot with one tire completely empty, sitting on the rim.(front right) The left front tire only had 30 pounds in it. We do not know how long the motorhome has been sitting like this.(not more then 10 days). With the Good Sam help both tires have been inflated back to 95 pounds. There seemed to have had faulty/leaky stems. new ones have been installed.
QUESTION... Is the right tire completely shot or is is stil safe to drive on it? We just got a TPM system and can keep an eye on the tires. All tires on our rig are about 5 years old.

Both tires must be inspected after demounting by a tire store that sells truck/RV tires. Seller of the brand you have is definitely preferred. Keep the receipt as proof if they say either tire is OK to use.

The 0 psi tire may have "kinked" or pinched the steel in the tire sidewall which could lead to a rapid air loss. The 30 psi tire may be OK but again MUST be inspected.

At 5 years it may just be good to go ahead and replace both or at least the 0 psi tire, but be sure to tell the tire store of their history.

Sorry for the bad news.

RE possible faulty valves. I assume you mean the rubber stem gaskets were leaking. I don't know if I have ever seen a bolt in valve fail if not damaged due to accident or being hit. Rubber valve parts or the entire valves should always be replaced whenever getting new tires.

bachler · 12-29-2013, 01:19 AM

I do not want to get into a He said she said.. When the tire manufacturer Was having wa hard time Making rubber Hard/elastic enough to be road worthey. he had a piece of rubber in his hand , when he got called outside of his lab/shop he accidently throw the piece on the stove that had gone out but it was still warm. when he came back in he found it put it asside when he picked it up later he found it had Cured to the appx. consisity he wanted.. Hens heat is not good. and is a result of underinflation. Now for side Zipper Blow outs. That is/was a common Blowout for the ZRV tire. I inflated to Factory LBS. and Blow 2 of them Out Less then 2 years old. 2.75 X 22.5 Michilen. The dealers said this was a common thing to happen... I know some will dissagree. That is good.. This happened to me... I now use the Green line, Michalin. Life is good