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08-19-2016, 07:08 AM
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#1
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Rivet Master
2017 25' Flying Cloud
Florence
, Alabama
Join Date: Dec 2015
Posts: 713
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What pressure to start with
Just got new 25FB FC. It has the GYM with 65psi max on the side. The AS placard has 65psi too. After a short trip I checked the pressures and they all were around 55. Now that we have AS loaded, estimating no more than 600-800 lbs, what should it air them up to? I have a TPMS coming in today so will install before next trip.
__________________
The Colonel and Southern Belle
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08-19-2016, 07:20 AM
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#2
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4 Rivet Member
1990 32' Excella
jonesboro
, Arkansas
Join Date: Aug 2002
Posts: 257
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I would run full pressure . Lower pressure leads to higher temps that lead to tire failure. Go to the forum on tires it has lots of info on brands and potential problems of some of them .Enjoy the trailer
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08-19-2016, 07:23 AM
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#3
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Rivet Master
Currently Looking...
Mantua
, Ohio
Join Date: Jul 2005
Posts: 7,062
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65 is what Goodyear and Airstream both recommend. That's cold pressure. If yours showed 55 after driving, they are too low.
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08-19-2016, 07:39 AM
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#4
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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We always run our GYM's at 65 psi on our two Airstreams, and had TPMS, tires worked fine.
Because of reliability concerns we eventually threw out the GYM's and TPMS, upgraded to 16" Michelin tires. Sidewall has 80 psi max but we don't need that much load capacity, so run these at 65 psi for a better ride.
__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts
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08-19-2016, 11:39 AM
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#5
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4 Rivet Member
1967 26' Overlander
Spartanburg
, South Carolina
Join Date: Jan 2011
Posts: 437
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Quote:
Originally Posted by dblee1950
Just got new 25FB FC. It has the GYM with 65psi max on the side. The AS placard has 65psi too. After a short trip I checked the pressures and they all were around 55. Now that we have AS loaded, estimating no more than 600-800 lbs, what should it air them up to? I have a TPMS coming in today so will install before next trip.
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Go to the nearest truck stop when you are fully loaded and weigh each trailer axle. Use the higher of the two weights and divide by two to get the load on each tire and look that load up in the tire manufacturer's load table on their web site or go to a tire dealer and get them to look up the specified pressure for that load. If you can weigh the load on each tire so much the better. Use the highest of the 4. I usually add a couple of pounds for added safety but the tire manufacturer should have put a safety factor in their numbers. I have been running GYM load range D tires on my '67 for many years at 43 psi with no problems. Max pressure is not always necessary or desirable. I get a pretty smooth ride.
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08-19-2016, 03:18 PM
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#6
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4 Rivet Member
2000 30' Excella
2014 30' Classic
Princeton
, Iowa
Join Date: Mar 2012
Posts: 302
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I messed with this for years, I finally did as so many say, put in 65 PSI when cold. The trailer pulls easier, and thing ride just as well in the trailer. I am sure you will get better wear from your tires. If mine start wearing in the middle, I will take a little out, so far they are wearing perfect.
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08-19-2016, 03:53 PM
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#7
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Rivet Master
1991 34' Excella
Princeton
, New Jersey
Join Date: Aug 2003
Posts: 7,070
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You start by using the tire MANUFACTURES recommended pressure as per the chart. The pressure printed on the side of the tire has nothing to do with reality.
My tire have 85 lbs printed on the tire. I run 45 and that is over inflated but I do it so I can run in on only 5 tires if necessary.
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles
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08-19-2016, 05:36 PM
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#8
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Rivet Master
2015 25' Flying Cloud
2016 30' Flying Cloud
Blenheim Ontario
, Ontario
Join Date: May 2015
Posts: 1,263
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My 30' FC came with 15" Michelin 'P' tyres and max sidewall is 50 psi. And CanAm says to use that figure cold.
My avg. Loading is about 7800-8000 lbs. And driving at 100-110 klicks on a 30C+ day doesn't seem to bother them. So says my 'Royal Canadian' feeler paw, and an 'NVision TPMS.
Go with the ' so called 'pros' recommendations and if possible get it in writing.
(Remember to CYA.)
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08-22-2016, 06:08 AM
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#9
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4 Rivet Member
1967 26' Overlander
Spartanburg
, South Carolina
Join Date: Jan 2011
Posts: 437
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Quote:
Originally Posted by MelGoddard
My 30' FC came with 15" Michelin 'P' tyres and max sidewall is 50 psi. And CanAm says to use that figure cold.
My avg. Loading is about 7800-8000 lbs. And driving at 100-110 klicks on a 30C+ day doesn't seem to bother them. So says my 'Royal Canadian' feeler paw, and an 'NVision TPMS.
Go with the ' so called 'pros' recommendations and if possible get it in writing.
(Remember to CYA.)
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Maybe it is different in Canada but I would never run "P" tires on my trailer. They don't have the sidewall strength to withstand sharp turns esp. turning while backing.
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08-22-2016, 06:13 AM
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#10
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Rivet Master
Currently Looking...
Mantua
, Ohio
Join Date: Jul 2005
Posts: 7,062
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That's what AS puts on some models.
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08-22-2016, 06:47 AM
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#11
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.-. -...
2017 25' International
Niagara-on-the-Lake
, ON Canada
Join Date: May 2016
Posts: 1,837
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Here is a copy of the GYM inflation table. We run 55 psi cold (as recommended by Can-Am) at our loaded weight on GYM ST 225/75R15. It generally climbs to 60 psi and 90 deg F when running in 30 deg C ambient as shown on our TST 507 TPMS. (Too high a pressure may cause excessive rough ride for the trailer and contents.)
P.S. I also monitor my spare tire.
__________________
Ray B.
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08-22-2016, 08:37 AM
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#12
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Rivet Master
2006 25' Safari FB SE
Spokane
, Washington
Join Date: Sep 2009
Posts: 1,858
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A Great Question
Tire inflation is one of the most important issues out there. It is not an easy answer since there are so many variables to deal with.
Basically a tire is "under inflated" when the pressure inside cannot carry the weight it is asked to carry. You need to know the weight of your trailer as it goes down the road. Weighing it is the best way but you can use the GVWR as a good estimation. Look at a chart like this,
http://www.maxxis.com/trailer/traile...nflation-chart
and inflate the tire so the weight rating is large enough to carry the trailer and have a decent buffer past that. I ran LRD Maxxis tires on my 25FB that has a GVWR of 7200. In the chart (and printed on the sidewall) the carrying capacity @ 65 was 2540. Multiply that by 4 to get a total capacity of 10,160 pounds. I felt comfortable with that amount so I ran my tires at 60-65. I have weighed my trailer a few times and I am usually running at 6500 lbs. Using 10,000 as a tire weight capacity estimate I have a 53% margin (if you are an engineer) or a 35% margin (if you are a business major).
I just replaced these tires with a LRE tire that will take 80 lbs of pressure for a weight rating of 2830 per tire. I will run them at 70 and still have more capacity than I had with my others.
When a tire has less pressure than what is on the sidewall it will flex more. I suppose this is the issue that makes people say the trailer rides better. That might be true but I don't think I could tell. I do know that the more flexing the more heat will be produced. It is the heat that does the damage. While I plan to run mine at 70, I will inflate them to the max when traveling in extremely hot conditions.
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08-22-2016, 08:59 AM
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#13
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Rivet Master
2017 25' Flying Cloud
Florence
, Alabama
Join Date: Dec 2015
Posts: 713
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Well, I set my tires to 65 per placard and installed my tpms. After two days on the road, psi only went to 72, highest, with temp up to 100, at times. When it rained, everything went down nicely. Will continue to monitor, tpms helps me keep an eye on tires for a little reassurance until I'm ready to go the 16", Michelin E route or better.
__________________
The Colonel and Southern Belle
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08-22-2016, 09:28 AM
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#14
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Living Riveted since 2013
2016 Interstate Lounge Ext
Green Cove Springs
, Florida
Join Date: Dec 2013
Posts: 8,210
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Completely agree that the load chart is worth using along with knowing what weight is actually on your trailer's wheels.
We have an International Signature 27FB and for us 65PSI cold is too high.
We generally start at 58-60 cold and our tires have served us well up to now. (We realize we are not a statistically significant sample, btw.)
We used to be proud members of the 65PSI cold club. Then we met the Mojave Desert. Not a happy moment when the TPMS was reading out 70+ PSI and when we stopped for a break the sidewalls appeared to be bulging uncomfortably against the structure of the tire. We spent some quality time with a Goodyear dealer in Victorville, CA, who told us the tires were fine but 65 cold was clearly too high for our use and we should start out around 58. We've done that ever since and everything's been fine thus far.
Oh and yes, we're big fans of using a TPMS to monitor all 5 tires (including the spare).
Hope that helps.
Quote:
Originally Posted by Adventure.AS
Here is a copy of the GYM inflation table. We run 55 psi cold (as recommended by Can-Am) at our loaded weight on GYM ST 225/75R15. It generally climbs to 60 psi and 90 deg F when running in 30 deg C ambient as shown on our TST 507 TPMS. (Too high a pressure may cause excessive rough ride for the trailer and contents.)
P.S. I also monitor my spare tire.
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__________________
Rocinante Piccolo is our new-to-us 2016 Interstate Lounge 3500 EXT
(Named for John Steinbeck's camper from "Travels With Charley")
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08-22-2016, 09:38 AM
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#15
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Rivet Master
2012 25' Flying Cloud
Battle Lake
, Minnesota
Join Date: Jun 2009
Posts: 7,714
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Not a huge fan of TPMS (we quit using it on the Airstream with a change to 16" Michelin), why spend the money to monitor the trailer spare? Our truck has no TPMS on its spare, but that seems a better place to put it.
__________________
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts
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08-22-2016, 09:51 AM
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#16
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Living Riveted since 2013
2016 Interstate Lounge Ext
Green Cove Springs
, Florida
Join Date: Dec 2013
Posts: 8,210
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Having a sensor on the spare means we know whether our spare is flat before we need it. Also, it's possible, even for a Michelin, to go flat quickly with a big enough nail through it.
No big deal whether you agree with that, do what seems best for you.
__________________
Rocinante Piccolo is our new-to-us 2016 Interstate Lounge 3500 EXT
(Named for John Steinbeck's camper from "Travels With Charley")
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08-26-2016, 08:53 PM
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#17
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4 Rivet Member
2015 27' Flying Cloud
Bozman
, Maryland
Join Date: Jul 2014
Posts: 294
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Just finished 30,000+ mile trip in west and southwest (including two cross-continent trips) in our FC27 on OEM GYMs. Ran them at 65 psi cold at no more than 65 mph continuous. No issues with the tires and tread wear appears to be even. One puncture (tire deflated overnight at a RV park in Sioux Falls; how convenient is that!) which was successfully plugged and one other tire has a very slow leak (loses about 5 psi/day starting at 65). I do not have a tpms but I do check pressures every morning before we hit the road. No popped rivets or other indicators of stress in the trailer.
Currently, we're living in an apartment but will probably resume full-timing next March. I suppose I ought to replace the tires before then but they just don't look that worn.
Anyway, that's a data point on tire pressure and ambient temperature ranged from 30 degrees to 100 degrees F.
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