Author Topic: Tire Pressures  (Read 3635 times)

Mark Beavin

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Tire Pressures
« on: January 10, 2019, 01:28:59 PM »
What are people doing for tire pressure settings. My badge on the coach show total GVW and recommends 100 in the front and 95 rear. I weighed the coach at a Cat Scale and according to the chart in my chassis book with Toyo tires I should run 70 front and 85 rear. What do you all run? Tires are good to 110 PSI.
Mark Beavin  Judi Binderman
FMC 491464
1996 Beaver Monterey 30'
3126 Cat Diesel 250 HP

Jerry Emert

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Re: Tire Pressures
« Reply #1 on: January 10, 2019, 02:06:05 PM »
With the info you provided I would run 75 front 90 rear.  Air pressure makes a big difference in ride and handling.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH
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Gerald Farris

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Re: Tire Pressures
« Reply #2 on: January 10, 2019, 03:11:41 PM »
Mark,
Did you weigh the coach at each wheel? If not, you do not know what air pressure to run because these coaches can vary over a 1,000 lbs. from one side to the other, and the proper air pressure for an axle is determined by using the heaviest side. So taking the total weight of an axle and dividing it in half does not work. Also the coach needs to be weighted at each wheel as it is used and that includes clothes, food, tools that you carry, full tanks including fuel, and a loaded trailer if you tow one. Until you know you wheel loading, I always recommend that an owner run the maximum air pressure for the tire because an over inflated tire may not ride as well as one properly inflate, an under inflated tire will blowout or receive internal damage that will cause a future failure, and that is an unnecessary safety risk. A blowout usually causes expensive damage if not a wreck that can be very serious.     

Gerald
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Doug Allman

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Re: Tire Pressures
« Reply #3 on: January 10, 2019, 03:41:09 PM »
I fully agree with Gerald as we when we owned our Contessa we drove with underinflated tires, 80 lbs,  so we could get a smoother ride.  We were not members of the BAC at that time and did not have access to the Forum as we do now.
Case in point, 1.5 year old Michelin with less than 4000 miles on it blew out on right front steer at 65 mph with DW driving. Thank the Lord for the Safe-T-Plus we had installed as it went straight down the highway until we coasted to slow enough speed to pull onto shoulder.
Run your tires at maximum pressure to prevent sidewall damage. Tire Distributor in Denver would issue no credit as it was a side wall blow out and stated it was due to UNDERINFLATION. Tred looked just fantastic but that is the wrong view to look at a coach tire.
In retrospect They were right as it had a 12 inch rip around the sidewall and I was the culprit wanting a smoother ride. Was not happy about it then but certainly understand it today and thankful we had a guardian angel riding with us that day. Learn to like the little more harsh ride for Safetys sake as you do not want to experience a blow out in any position.
Gerald gives you an understanding from knowing numerous beavers that have had this event. Not all good ones.

Steve Huber Co-Admin

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Re: Tire Pressures
« Reply #4 on: January 10, 2019, 03:46:19 PM »
Mark,
This writeup will step you through the procedure to arrive at the correct pressures for your coach. It's found in Common Problems in the Technical section of the BAC web site.  http://beaveramb.org/acadp_listings/tire-inflation-guidelines/
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Bill Lampkin

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Re: Tire Pressures
« Reply #5 on: January 10, 2019, 04:43:02 PM »
One common misconception is that the MAX inflation pressure shown on the tire sidewall is somehow the pressure that will cause your tire to 'blow up" due to overinflation. Not the case; rather, it is the MINIMUM pressure required to carry the MAXIMUM LOAD as stated on the tire sidewall. So, if your 4 corner or CAT weights show your steers are at maximum weight, then you should run the MAX pressure as stated on the sidewall. I'm with Gerald, who ever heard of a tire failure from 'too much' pressure. Its under pressure that causes an overheated tire that causes a sidewall blowout. Scary event, Doug, and am glad all came out well for you. Check your corner or axle weights, check the tire inflation chart and add 10-15% to that pressure. Google RVtiresafety; all you need to know about tires from a now-retired tire engineer, good reading.
2005 Patriot Thunder Lexington, 3 slides
40' tag axle (short wheelbase)
525 hp C13

"Goin where the weather suits my clothes..."
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