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10-01-2015, 01:58 AM
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#1
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Montana Master
Join Date: Nov 2013
Location: Willow Spring, NC
Posts: 992
M.O.C. #13909
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tire pressure vs. weight- the correct answer
I've been riding around with maximum pressures in my tires to be safe. At the recent National MOC rally, I had my truck and trailer weighed by tire position to see what the facts really were.
My measurements all came out really good, thanks in part to my DRW TV and G614 tires. However, I found out that at my current weight I could reduce the pressure in my G614s to 95-100 psi instead of 110 psi, which is the maximum. Trey Selman from RV Safety showed me the tire pressure recommended chart for both my truck and trailer based on my weight. They add 5 psi for safety and this will allow me to run 95-100 psi and decrease uneven wear in the tires and reduce the chance of impact damage to the tires by potholes, etc.
I also can reduce my TV tire pressures to provide a smoother ride.
Best $60 I've spent.
I also found out that the CAT public scales don't really help RVers because our weight is uneven across the axle. The fridge side is always the heaviest. So my pressures are set for the heaviest side and not the average.
__________________
Jim & Martha Abernathy
2014 Montana 3402RL Level UP, Sailun S637's, TST 507, 500W solar
2014 Ram 3500 Laramie® 4x2 diesel dually crew-cab 3.73 axle, Reese R20
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10-01-2015, 02:53 AM
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#2
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Site Team
Join Date: Jun 2011
Location: Wilsey
Posts: 18,799
M.O.C. #11455
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I have always run mine at 106-108# even though I could use less. Better milage and no problem with tire wear or damage for me anyway.
__________________
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, and 2013 HC 343RL
Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, replaced chairs, sun screens, added awnings, etc.
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10-01-2015, 03:21 AM
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#3
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Montana Master
Join Date: Mar 2012
Location: Davison
Posts: 786
M.O.C. #12331
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105#. I like the infomercial by-line "Set it and forget it!".
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10-01-2015, 06:12 AM
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#4
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Montana Master
Join Date: Jan 2005
Location: North Ridgeville
Posts: 20,229
M.O.C. #2839
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Yes one can learn a lot by being weighed .We do the same thing run the G6-14s at 105psi.Truck 65 psi front and 60 psi on the dualies.
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10-03-2015, 08:02 AM
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#5
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Montana Master
Join Date: Jan 2015
Location: Taylors
Posts: 562
M.O.C. #15948
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Vehicle manufacturers set recommended tire inflation pressures for all Original Equipment (OE) tires. By regulations they are the only ones responsible for that action.
The recommended tire inflation pressures set by the vehicle manufacturer becomes the minimum standard for all subsequent tire fitments to that vehicle. In other words the load capacity of the OE tires must be maintained because they were established as appropriate for that vehicle. So, if OE tires provided 3420# of load capacity the new recommended tire pressures for G614 replacements must equal or exceed 3420# by inflation. That would be about 96 psi. To get a little extra from the tire I’d go to 100 psi but 96 is the minimum according to the G614 load chart.
There are no provisions anywhere in the regulations or tire industry standards that allow less tire inflation pressures than those established for the OE tires and their replacements. Of course there are situations outside of the normal operating parameters but they are few and usually.
Setting RV trailer tire inflation pressures to accommodate the load carried is a poor recommendation by whoever makes it. A 1 psi loss of inflation pressure will cause such tires to be overloaded. You can lose a single psi by hitting a curb or pothole or just dropping off the slab you were parked on all weekend. Sure, it’s uncommon but it can happen.
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10-03-2015, 08:05 AM
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#6
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Montana Master
Join Date: Jan 2015
Location: Taylors
Posts: 562
M.O.C. #15948
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Vehicle manufacturers set recommended tire inflation pressures for all Original Equipment (OE) tires. By regulations they are the only ones responsible for that action.
The recommended tire inflation pressures set by the vehicle manufacturer becomes the minimum standard for all subsequent tire fitments to that vehicle. In other words the load capacity of the OE tires must be maintained because they were established as appropriate for that vehicle. So, if OE tires provided 3420# of load capacity the new recommended tire pressures for G614 replacements must equal or exceed 3420# by inflation. That would be about 96 psi. To get a little extra from the tire I’d go to 100 psi but 96 is the minimum according to the G614 load chart.
There are no provisions anywhere in the regulations or tire industry standards that allow less tire inflation pressures than those established for the OE tires and their replacements. Of course there are situations outside of the normal operating parameters but they are few and unusual.
Setting RV trailer tire inflation pressures to accommodate the load carried is a poor recommendation by whoever makes it. A 1 psi loss of inflation pressure will cause such tires to be overloaded. You can lose a single psi by hitting a curb or pothole or just dropping off the slab you were parked on all weekend. Sure, it’s uncommon but it can happen.
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10-03-2015, 04:16 PM
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#7
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Montana Master
Join Date: May 2011
Location: Hixson
Posts: 3,436
M.O.C. #11397
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Actually CAT scales can be used to get individual tire weights. Weigh the Fiver normally and then pull around again and put the tires on one side off the scale and then split the two remaining on the scale between two platforms.
Should only be simple math from there.
Second time on the scale is considered re-weigh.....not sure what the charge is now but used to be $1.00 for re-weigh.
Entire process less than $20.00.
__________________
2018.5 Montana 3791RD
Full Timers 9/1/2010 through 1/16/2020.
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10-04-2015, 02:58 AM
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#8
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Montana Master
Join Date: Jun 2006
Location: Madison
Posts: 1,239
M.O.C. #5906
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As mentioned in the first post, the RV weighing folks include a 5 lb. "fudge factor" in their pressure recommendation. That means that the 1 lb. pressure drop also mentioned will probably not be an issue. For us, the pressures recommended was the door sticker pressure on our truck and 110 on the Big Sky. We asked about running the truck at the tire sidewall pressure. They said that it wasn't a problem per se. At the lesser pressure the ride and tire wear would be best. At the higher pressure fuel mileage would be better, but the ride would be rougher and tire wear might be uneven.
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10-04-2015, 05:14 AM
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#9
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Montana Master
Join Date: Oct 2004
Location: Salem
Posts: 7,550
M.O.C. #2283
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Thanks CalandLinda. Great information.
Lynwood
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10-04-2015, 10:33 AM
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#10
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Montana Master
Join Date: Apr 2009
Location: Murrieta
Posts: 5,816
M.O.C. #9257
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I don't have a CAT scale near where I live. I use a moving and storage company nearby that just happens to have a truck scale to measure freight loads for folks they move. They charge me only $10 for all my private measurements since I don't need a certified weight(truck empty, truck loaded, with and without trailer, each axle, each side at front and rear axle, trailer only and one side of each trailer axle front and back. Then I use math to figure other side of the axle weights or truck weights and the pin weight. It's been a while since I last weighed my rig and now that I'm full timing I should really do a recheck.
The first time I ever did this I was overweight at the rear axle and thereby each axle at the rear of the trucks. Then I did some work on the rear truck axle springs and larger capacity tires and wheels and now all is good. But I do need a recheck since it's been a while and we are now fulltiming. I'm not too concerned since I believe since we started full timing we removed a lot of stuff we didn't use much. Since we replaced that removed stuff with more important full timing stuff, we need to reweigh.
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10-12-2015, 03:54 AM
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#11
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Montana Master
Join Date: Apr 2015
Location: Stafford Springs
Posts: 524
M.O.C. #17256
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Quote:
quote:Originally posted by jfaberna
I've been riding around with maximum pressures in my tires to be safe. At the recent National MOC rally, I had my truck and trailer weighed by tire position to see what the facts really were.
My measurements all came out really good, thanks in part to my DRW TV and G614 tires. However, I found out that at my current weight I could reduce the pressure in my G614s to 95-100 psi instead of 110 psi, which is the maximum. Trey Selman from RV Safety showed me the tire pressure recommended chart for both my truck and trailer based on my weight. They add 5 psi for safety and this will allow me to run 95-100 psi and decrease uneven wear in the tires and reduce the chance of impact damage to the tires by potholes, etc.
I also can reduce my TV tire pressures to provide a smoother ride.
Best $60 I've spent.
I also found out that the CAT public scales don't really help RVers because our weight is uneven across the axle. The fridge side is always the heaviest. So my pressures are set for the heaviest side and not the average.
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Totally agree! They were great. It was very comforting to find out I am within all my numbers and I to am running to much air in my tow vehicle.
__________________
Jason & Wendy
2014 Ford F-350 Lariat 6.7L PSD
2015 Keystone Montana 3711FL
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10-12-2015, 09:04 AM
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#12
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Montana Master
Join Date: Feb 2005
Location: Haysville
Posts: 4,261
M.O.C. #3085
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Quote "Setting RV trailer tire inflation pressures to accommodate the load carried is a poor recommendation by whoever makes it."
What ever floats your boat ... lots of people and businesses towing use inflation charts. If I ran max sidewall psi on my truck, I'd wear the center tread off my tires way before the edge tread. Un-needed rock hard inflation pressure jolts the heck out of what you're hauling. According to my TPMS ... I gain @8psi on a hot day once I get going down the road. I've often wondered how that figures in.
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10-12-2015, 09:19 AM
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#13
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Montana Master
Join Date: Feb 2007
Location: Winfield
Posts: 7,327
M.O.C. #6846
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I agree dieselguy, if that was the case, why would the tire manufacturers waste time and money by publishing load inflation charts? I go by the chart and typically add about 5 psi to the recommendation simply because I choose to do so.
Bingo
__________________
Bingo and Cathy - Our adventures begin in the hills of WV. We are blessed by our 2014 3850FL Big Sky (previous 2011 3750FL and 2007 3400RL) that we pull with a 2007 Chevy Silverado Classic DRW CC dually.
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10-12-2015, 11:50 AM
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#14
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Montana Master
Join Date: Jul 2013
Location: Aguanga
Posts: 606
M.O.C. #13601
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Art where is that scale at? I'm due for a another trip to the scales but don't want to drive out to Ontario to do it.
Quote:
quote:Originally posted by Art-n-Marge
I don't have a CAT scale near where I live. I use a moving and storage company nearby that just happens to have a truck scale to measure freight loads for folks they move. They charge me only $10 for all my private measurements since I don't need a certified weight(truck empty, truck loaded, with and without trailer, each axle, each side at front and rear axle, trailer only and one side of each trailer axle front and back. Then I use math to figure other side of the axle weights or truck weights and the pin weight. It's been a while since I last weighed my rig and now that I'm full timing I should really do a recheck.
The first time I ever did this I was overweight at the rear axle and thereby each axle at the rear of the trucks. Then I did some work on the rear truck axle springs and larger capacity tires and wheels and now all is good. But I do need a recheck since it's been a while and we are now fulltiming. I'm not too concerned since I believe since we started full timing we removed a lot of stuff we didn't use much. Since we replaced that removed stuff with more important full timing stuff, we need to reweigh.
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10-12-2015, 02:55 PM
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#15
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Montana Master
Join Date: Mar 2011
Location: Okeechobee
Posts: 2,150
M.O.C. #11206
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Hi
The early production run of the Goodyear G-614 had uneven tread wear where the outside edges of the tread wore faster than the rest of the tire. This commonly is the result of low tire pressure but I have always run ours at 110 Psi cold.
When I got my second set of G-614 tires my commercial truck tire dealer recommended keeping them at 110 Psi and so fare with balanced wheels I don’t have any unusual wear and now have about 25,000 miles on the second set. I have 85,000 miles on the trailer.
I run the tire pressures listed on the truck door post in the TV tires and commonly get 65,000 out of a set of tires. At 149,000 miles I am on my third set of TV tires.
Phil P
__________________
2009 Montana 3665RE
2009 Duramax 3500 DRW quad cab
personal web page https:// www.sallyscoffees.com
If you get a page not available then remove the "s" after HTTP
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11-13-2015, 01:24 PM
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#16
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Montana Fan
Join Date: Dec 2013
Location: Elk Grove
Posts: 103
M.O.C. #13966
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I run my G614's at 105 and use a TireMinder system to monitor them. I had my rig weighed at the rally ...year before last. They recommended 60 psi for the front tires and 80 for the rear...when towing. I have a 2011 Dodge 2500 4x and when NOT towing it rides very hard. In this regard, I carry a CO2 air system with me which allows me...when not towing... to reduce the rear tires to 45 psi for a more comfortable ride...and then increase the pressure using the CO2 air system to 80 psi ...before we tow again. To increase the pressure from 45 to 80 psi takes 4 minutes per tire.
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11-14-2015, 04:28 PM
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#17
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Montana Fan
Join Date: Oct 2015
Location: Round Rock
Posts: 475
M.O.C. #17905
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Some really informative stuff here on tires. I am really interested in tire tips since I have replaced quite a few tires on my last 5ver. We recently purchased a new monty but as you know they come with ST Trailer King tires. China I think. I always wanted a G-rated tire so I don't have to buy tires every time I turn around. What are you guys running.....besides Goodyear 614's? I have no problem with Goodyear, just wanted to get opinions on some others as well. Probably end up with 614's.
__________________
Pete & Joan & "Honey" fur-baby.
2015 Montana 3611RL 2012 F350 6.7 DRW Lariat
Disc Brakes & Sailun 14 ply S637
6-pt Hydraulic leveling
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11-14-2015, 05:14 PM
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#18
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Montana Fan
Join Date: Oct 2015
Location: Round Rock
Posts: 475
M.O.C. #17905
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Forget my earlier post...I found all the info on another post. Just didn't look long enough.
__________________
Pete & Joan & "Honey" fur-baby.
2015 Montana 3611RL 2012 F350 6.7 DRW Lariat
Disc Brakes & Sailun 14 ply S637
6-pt Hydraulic leveling
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11-15-2015, 01:12 AM
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#19
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Montana Master
Join Date: Jul 2006
Location: K.C.
Posts: 11,731
M.O.C. #5980
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Quote:
quote:Originally posted by MP1
I run my G614's at 105 and use a TireMinder system to monitor them. I had my rig weighed at the rally ...year before last. They recommended 60 psi for the front tires and 80 for the rear...when towing. I have a 2011 Dodge 2500 4x and when NOT towing it rides very hard. In this regard, I carry a CO2 air system with me which allows me...when not towing... to reduce the rear tires to 45 psi for a more comfortable ride...and then increase the pressure using the CO2 air system to 80 psi ...before we tow again. To increase the pressure from 45 to 80 psi takes 4 minutes per tire.
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Miles, I too carry the CO2 for the same reason. Fast, silent and powerful CO2 system. I have a 5# Bottle with compound regulator gauges attached with a bracket to my tool box in the truck. I don't know why more folks don't use this system. I also have a Viair 450 hard-wired and a 2.5 gallon tank under the truck, but the CO2 system if far faster and more convenient.
Stay safe out there.
Ozz
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