Best Tire Pressure

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wjhgolf
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Joined: Thu Oct 13, 2011 11:03 am

Best Tire Pressure

Post by wjhgolf »

Like most of you, our 24ft RB recommended tires pressures on the door jam read 65psi F and 80 psi R. We have new Michelin tires and have been running them at 60psi F and 70 psi R (cold, of course). Obviously, those pressures can jump to 65+ and 80+ pretty quickly when on the highway in warm weather. We have a good TPM system (Tire Minder Research), so I can set them anywhere I want with the + and - protection of about 10% before I get an alarm. What pressures do you run considering; fuel economy, tire life and ride/handling?
Bill and Sharyn Hill
Clarkston, MI
2002 24ft RB
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whemme
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Post by whemme »

There is only one accurate way to determine the correct tire pressures to use for your Born Free coach (or any other RV) and that is to get the four corner weights of your coach in the normal down the road running condition including occupants aboard. Finding a truck scale that can weigh each corner of your coach separately can be a challenge sometimes.

Click on the blue Download button on the right side of the window below to view and/or print out a tire inflation graph that applies to all brands of LT225-75R16 Load Range E Tires. The pressures shown are for tires that have not been driven for at least an hour.

Since you have invested in a TPMS, you might as well set the pressures correctly. There is no need to run pressures higher than indicated in this graph - running higher pressures just adds harshness to the ride quality.

Using this graph, I run 58 psi in my fronts and 73 psi in the rear duals on my 2002 BF 26' RSB coach.
Attachments
Tire Inflation Graph for all Brands of LT225-75R16 Load Range E Tires.pdf
Click on the blue Download button to the right to view and/or print out the tire inflation graph.
(4.91 KiB) Downloaded 373 times
Last edited by whemme on Fri Feb 01, 2013 2:23 pm, edited 1 time in total.
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TheBizMan
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Post by TheBizMan »

I run 65 front and 75 back on my BFT. I also have a TPMS so I can watch them.
Lee-TheBizMan
2005 BFT - named "Tilly"
2012 Scion xD "Toad"

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stevek
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Post by stevek »

Are the TPMS worth getting for most people?
I am debating, plus trying to learn.
So, they screw on to the tire valves.
Do they have batteries in them?
And there must be a receiving unit on the dash.
I see Amazon has a kit with 4 for about $140 + you would have to buy 2 more sensors. So I guess for under $200. Seems reasonable.
How accurate are they?
Whats a good brand?

All this.. versus, just getting out and checking your air pressure manually.
And the pros and cons?
Something to think about. :lol: THANKS
Steve
2011 Born Free 22 foot RSK, rear side (corner) kitchen, E350, 29k miles.
Our first motorhome. Lots to learn. Thanks.
CA/OR border
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whemme
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Post by whemme »

Steve,

I have used a PressurePro TPMS system for 7 years now and am will satisfied with how well it works. I monitor the 6 tires on my Born free coach and also the 4 tires on my toad.

I will try to answer your questions below.

Are the TPMS worth getting for most people? I think so.
I am debating, plus trying to learn.
So, they screw on to the tire valves. Yes
Do they have batteries in them? Yes
And there must be a receiving unit on the dash. Yes
I see Amazon has a kit with 4 for about $140 + you would have to buy 2 more sensors. So I guess for under $200. Seems reasonable.
How accurate are they? My PressurePro sensors are accurate within 1.0 psi according to a precision digital tire pressure gauge that I also use.
Whats a good brand? Pressure Pro in my opinion but there are other good brands out there but I only have first hand experience with the PressurePro system. As I recall, the PressurePro monitor costs $190 and each of the sensors cost $50 each. My first set of sensors lasted 5 years before the internal batteries went dead. Exchange replacement sensors cost $35 each.

Here is a factory website link to the proper system for an RV and toad: http://www.advantagepressurepro.com/ind ... etailId=61

You will find many PressurePro system distributors if you do a little searching on the internet.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
oliverpsmile
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Post by oliverpsmile »

Regarding battery life in the sensors I think they would last longer, provided that they are used only when driving. Similar technologies are implemented in the electronic tags for paying highway tolls. They have batteries that are in use ONLY when activated by the radio signal from the reader. The rest of the time they just keep CMOS (very low current dependable electronic circuits) alive. My personal tag from NYC is 13 years old and still active.

In addition, I totally agree with Bill. This is my second Pressure Pro (first was sold with the previous BF) and it is priceless. It constantly (every minute or so) monitors the tire pressure. Preventing the damage from just about to blow up a tire, is well justified expense.

Also you feel god to be in control. :D

Bill:
Your initial pressure 58/73 cold is "how cold". And what is your running pressure during a trip say at 50 degrees or 90 degrees?.
Oliver P Smile
2005 26ft RSB
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whemme
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Post by whemme »

Oliver,

The 58 front/73 rear psi pressures are with the tires at whatever ambient outside temperatures happen to be. Of course what happens when I set the pressures before I leave Iowa where it is rather cold, when a get about half way to Phoenix since generally the ambient outside temperatures will be higher then the at rest tire pressures will need to be reduced back down to 58/73. Then again arriving in the Phoenix area, they will probably need to be reduced again.

My experience is that after traveling 10 or 15 miles, the running tire pressures increase approximately 10 to 12 psi above the non-running pressures.

If the the outside temperature is 50 degrees F and I set my non-running tire pressures to 58/73, I can expect to see a 10 to 12 psi increase then after running 10 to 15 miles. If the the outside temperature is warmer at 90 degrees F but I set my non-running tire pressures again to 58/73, I can expect to see the same 10 to 12 psi increase then after running 10 to 15 miles.

And my 5 year sensor battery life was based on removing the sensors from the tires anytime the coach was parked for more than a week. Leaving them installed full time will most likely shorten their life considerably.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
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Mel Wilbur
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Post by Mel Wilbur »

I have been using using the Tire Sentry system by Fleet Industries for many years with no problems. The feature I do like is that the sensors use replaceable watch type batteries (#357) which according to the company last for 24 to 36 months and signals when low and need replacing. Like Bill, when in storage for a month or more I remove them to extend the life of the battery. Depending on where you purchase the batteries the cost ranges from $1.25 to $2.00 each (Home Depot sells a package of 3 for $5.95). Two are required for each sensor, still a reasonable cost for piece of mind when traveling.
Mel & Connie
Roger
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Joined: Sat Oct 18, 2008 10:19 pm

Post by Roger »

Remember HEAT is the enemy of tires!
The higher the inflation pressure the less the tires flex and the cooler they run. The tire sites I've seen do NOT recommend you reduce inflation pressures after running or when you get to a warmer area. The reason is simple. If you go to a cooler area, then you run the risk of running the tires underinflated and causing possible tire damage. Also, if you don't have your own compressor, it's very difficult to find someplace to reinflate your tires.
If you live in a warm place and are traveling up north to cooler weather, you
might want to increase the inflation pressure before you leave home.

Regards, Roger
1999 24RB
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bcope01
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Post by bcope01 »

Another perspective.....

I've owned bicycles, motorcycles, cars, vans, trucks, cargo trailers, boat trailers, travel trailers, motorhomes, and yes wheelbarrows with inflatable tires, over the last 50 plus years, and until I purchased my Smart Car in 2008 with OEM TPMS, I have never used TPMS devices to monitor tire pressure. If installing and using TMPS devices on your Born Free gives you peace of mind, then so be it. I'll just continue to do what I have always done with regard to tire pressures, and that is keep an eye on my tires and periodically check tire pressures. :D

Bill
Barb & Bill
2004 Born Free 22' Built for Two (Sold)
no longer towing a 2008 Smart ForTwo

Escondido, CA
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whemme
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Post by whemme »

Roger,

I disagree with the when you get to a warmer area part of your statment: The tire sites I've seen do NOT recommend you reduce inflation pressures after running or when you get to a warmer area.

Please refer me to a tire site that says that.

Example situation: You inflate the rear duals of a Born Free coach to 80 psi when up north when the outside air temperature is 20 degrees F, the maximum pressure rating for LT225-75R16 Load Range E tires. Then you travel to the deep south where the outside air temperature is 80 degrees F. I would guess that at that temperature without the additional warmup from running down the road that the inflation pressure will now be at approximatley 90 to 95 psi and would increase to maybe 102 to 107 psi when traveling.

These resulting pressures would be way beyond the ratings for both the tires and the metal rims themselves.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
Roger
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Joined: Sat Oct 18, 2008 10:19 pm

Post by Roger »

Here's one, Bill:

http://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf

Of course, common sense has to be factored in here also! I was thinking of
Phoenix on a warm day (105 F). If you reduced your tire pressure to normal
and then drove to Flagstaff at night, your tires would be seriously underinflated. Tires and rims are designed to handle increased pressures due to changes in ambient temperature and heat from running. Constantly
fiddling with tire pressures to compensate for normal heat buildup is unneccessary.

Regards, Roger
1999 24RB
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Dallas Baillio
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Post by Dallas Baillio »

I've been on the road for 4 months and 12,500 miles with ambient temperatures from 6 to 85 degrees. When I've checked cold tire pressures they have been close enough to the 65/80 recommended.

If you have a TPMS I am sure you have an extra bit of piece of mind, but then you have to monitor and replace the batteries in the TPMS :!: Have you gained piece of mind or traded one worry for another?

I think a TPMS is a good idea for safety. I imagine they were first added to newer cars because drivers no longer can find a full service gasoline station and don't bother to check tire pressures themselves. I think they are now a federal mandate. They may soon appear as standard equipment on the Ford motorhome chassis.

But for me I am like bcope. I check my tires and if they are close to 65 psi front, and 80 psi rear, I am satisfied.
.
Dallas Baillio
2001 26RSB
Born Free Leap'n Lions RV Club Member
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whemme
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Post by whemme »

Roger,

That Goodyear document is full of good information but unfortunately after throughly reading pages 5 & 6 I could not find where it says what you indicated in the blue print copied in my earlier post above. What it does say on page 5 is the following:

When to check your RV or trailer tire pressure:
• Before and after storing your vehicle
• On long trips, every morning
• On short trips, before you leave and when you return home
• At least once per month while the vehicle is in storage

Doing what is recommended above is really easy with a TPMS.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
Roger
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Joined: Sat Oct 18, 2008 10:19 pm

Post by Roger »

Next paragraph down, third sentence:

"Do NOT bleed air from hot tires"

Regards, Roger
1999 24RB
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