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07-19-2022, 05:58 AM
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#21
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Senior Member
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
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Quote:
Originally Posted by hawghauler
You spent extra money for increased load capacity under inflation sounds counterproductive imo 80 psi or you're just wasting money
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In the world of tire inflation, underinflation is when PSI settings below vehicle manufacturer recommendations are used.
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07-19-2022, 06:02 AM
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#22
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Senior Member
Join Date: Jan 2021
Location: USA
Posts: 278
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Well all in all I see no disadvantage to going to 80PSI. Rims will handle it, stems will handle it, tires will handle it.
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07-19-2022, 06:15 AM
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#23
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Senior Member
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
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Quote:
Originally Posted by JRTJH
The below listed specs do not include the "magic of deducting tongue weight to get lighter axle weight"... Many people will argue that the axles don't carry the weight that's on the tongue, but just as many will ask, "What happens when you hit a pothole or a bump in the road or a railroad crossing and the axles bounce? Doesn't that increase the "load" on the axles" during that event?".....
Anyway:
Specs on the trailer:
empty weight: 3405
Cargo cap: 1295
GVWR: 4700
Tires: 2830 @80 PSI x2 = 5660 @80 PSI load capacity
5660-4700 = 960 remaining capacity.
Recommendations are for tire "reserve capacity" of 15% above rated weight
15% of 4700 is 705, so essentially, having 960 pounds of reserve capacity at 80 PSI is only 255 pounds more than "minimum"....
Or, to look at it as "individual tire capacity" at 80 PSI you're only 127.5 pounds "over the minimum".....
Do you really want to "air down those tires on a single axle trailer" ?????
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Please explain what "airing down" stands for? The recommended inflation pressure for the OE tires provides a total of 2540# per tire at 65 PSI for a total load capacity of 5080#. That's 680# above maximum GAWR load capacity and exceeds any industry recommended load capacity reserve capacities.
The 80 PSI molded on the tire sidewall is not a recommendation. It's a factual statement from its manufacturer that it can provide its maximum load capacity (also molded on the tire sidewall) at 80 PSI.
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07-19-2022, 06:20 AM
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#24
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Senior Member
Join Date: Apr 2022
Location: Middletown PA
Posts: 149
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Quote:
Originally Posted by CWtheMan
In the world of tire inflation, underinflation is when PSI settings below vehicle manufacturer recommendations are used.
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Yep and it says 80 psi on the sidewalk so less than 80psi constitutes under inflation
Quit playing word games to make yourself feel more intelligent than another
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07-19-2022, 06:23 AM
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#25
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Senior Member
Join Date: Nov 2017
Location: Mico, TX
Posts: 7,447
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Quote:
Originally Posted by hawghauler
Yep and it says 80 psi on the sidewalk so less than 80psi constitutes under inflation
Quit playing word games to make yourself feel more intelligent than another
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Dave, By poking the tire expert(s), you will personally be responsible for this thread stretching to 708 pages.
__________________
wiredgeorge Mico TX
2006 F350 CC 4WD 6.0L
2002 Keystone Cougar 278
2006 GL1800 Roadsmith Trike
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07-19-2022, 06:27 AM
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#26
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Site Team
Join Date: Mar 2011
Location: Gaylord
Posts: 26,979
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Quote:
Originally Posted by CWtheMan
Please explain what "airing down" stands for? The recommended inflation pressure for the OE tires provides a total of 2540# per tire at 65 PSI for a total load capacity of 5080#. That's 680# above maximum GAWR load capacity and exceeds any industry recommended load capacity reserve capacities.
The 80 PSI molded on the tire sidewall is not a recommendation. It's a factual statement from its manufacturer that it can provide its maximum load capacity (also molded on the tire sidewall) at 80 PSI.
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Pretty simple, at least for me to understand: Airing down means "letting air out of the tire"....
Cal, recheck your math. The trailer GVWR is 4700 pounds. Not counting the "magic reduction of tongue weight", that's not 680 pounds above the maximum GVWR load capacity. 5080-4700=380, not 680...
So, it's a matter of "where you pick the numbers" to do the math.... I choose to look at the whole trailer while you choose to only calculate based on the axle rating. Using your math, the tires on my trailer are 340 pounds UNDER the maximum axle rating of 6000 pounds. Are you saying my tires can't support the 10K GVWR on my trailer ???
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
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07-19-2022, 06:44 AM
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#27
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Senior Member
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
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Quote:
Originally Posted by JRTJH
Pretty simple, at least for me to understand: Airing down means "letting air out of the tire"....
Cal, recheck your math. The trailer GVWR is 4700 pounds. Not counting the "magic reduction of tongue weight", that's not 680 pounds above the maximum GVWR load capacity. 5080-4700=380, not 680...
So, it's a matter of "where you pick the numbers" to do the math.... I choose to look at the whole trailer while you choose to only calculate based on the axle rating. Using your math, the tires on my trailer are 340 pounds UNDER the maximum axle rating of 6000 pounds. Are you saying my tires can't support the 10K GVWR on my trailer ???
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This is an excerpt from the standard the RV trailer manufacturer MUST follow when building trailers...." The sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567."
This was in post #14. Certified vehicle GAWRs are used by the RV trailer industry for the purpose of tire selections and load capacities.
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07-19-2022, 07:19 AM
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#28
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Site Team
Join Date: Mar 2011
Location: Gaylord
Posts: 26,979
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Quote:
Originally Posted by CWtheMan
This is an excerpt from the standard the RV trailer manufacturer MUST follow when building trailers...." The sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label required by 49 CFR part 567."
This was in post #14. Certified vehicle GAWRs are used by the RV trailer industry for the purpose of tire selections and load capacities.
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And, to be as "blunt as I possibly can without insulting anyone"....
That "standard for the RV trailer manufacturer" was promulgated by the same people who tell us that there's no energy crisis and when we switch to EV's, all inflation is going to "suddenly disappear" and China will be our friend, providing all the microchips we need to resume production of airplanes, trains and automobiles.....
They just "forgot to mention" that EV's use more microchips and more energy than current vehicles or that more microchips are used in making small appliances, medical equipment and televisions than in making automobiles....
I won't apologize for not putting faith in what the "gubmint" establishes as a rule for how to manage RV safety weight standards any more than I would trust them to balance the budget.....
So.... trust the "gubmint" standards if you want, after all, they say that "china bombs are quality tires"..... After all, they do meet the "gubmint standards for tire quality"......
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
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07-19-2022, 07:30 AM
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#29
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Site Team
Join Date: Oct 2011
Location: Joppa, MD
Posts: 11,741
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We'll now you've seen more numbers than a loan manager trying to sell you a variable rate mortgage with PIP. I have the same tires on 2 axles, put on my second set this spring. Original tires were "D" rated and went to an "E" rating. Inflate to 80 psi, get a TPMS and travel with confidence. Don't try to over think it.
__________________
Marshall
2012 Laredo 303 TG
2010 F250 LT Super Cab, long bed, 4X4, 6.4 Turbo Diesel
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07-19-2022, 07:30 AM
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#30
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Senior Member
Join Date: Apr 2022
Location: Middletown PA
Posts: 149
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Quote:
Originally Posted by wiredgeorge
Dave, By poking the tire expert(s), you will personally be responsible for this thread stretching to 708 pages.
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George
😂😂😂
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07-19-2022, 08:08 AM
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#31
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Senior Member
Join Date: Jan 2021
Location: USA
Posts: 278
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Ha ha, I started a tire storm here didn't I?
In any case I think I'll stick with 80PSI.
Thanks for all the info everyone!
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07-19-2022, 09:05 AM
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#32
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Site Team
Join Date: Mar 2011
Location: Gaylord
Posts: 26,979
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Quote:
Originally Posted by Old_Stevenick
Ha ha, I started a tire storm here didn't I?
In any case I think I'll stick with 80PSI.
Thanks for all the info everyone!
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Same as Marshall does, same as I do and same as most people who switch to LRE tires. Increasing the load range and increasing the tire pressure to the maximum sidewall pressure increases the load carrying capacity which directly relates to increased safety margin....
Just like buying a 5 pound bag of sugar and only using 4 pounds and tossing the rest in the trash can.... Just like buying a 4 pound bag of sugar and using all of it.... At least that's what the "sugar manufacturers" will tell you.....
Sweet is not equal, tires are not equal and safety margins are not equal... JMO, YMMV, but......
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
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07-19-2022, 09:15 AM
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#33
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Senior Member
Join Date: Nov 2017
Location: Mico, TX
Posts: 7,447
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Quote:
Originally Posted by JRTJH
Same as Marshall does, same as I do and same as most people who switch to LRE tires. Increasing the load range and increasing the tire pressure to the maximum sidewall pressure increases the load carrying capacity which directly relates to increased safety margin....
Just like buying a 5 pound bag of sugar and only using 4 pounds and tossing the rest in the trash can.... Just like buying a 4 pound bag of sugar and using all of it.... At least that's what the "sugar manufacturers" will tell you.....
Sweet is not equal, tires are not equal and safety margins are not equal... JMO, YMMV, but......
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John, PLEASE... go through the sugar analogy. It is hard to comprehend unless you know the maximum weight rating of the sack it goes into! Is the rating for the sack the same if you turn it upside down? What happens.... never mind, this will only stretch this discussion out farther and farther.
OP: 80 PSI. Use metal valve stems. Use an accurate air gauge. Use a TPMS system. That covered it as if it already hadn't been covered!
__________________
wiredgeorge Mico TX
2006 F350 CC 4WD 6.0L
2002 Keystone Cougar 278
2006 GL1800 Roadsmith Trike
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07-19-2022, 09:44 AM
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#34
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Site Team
Join Date: Mar 2011
Location: Gaylord
Posts: 26,979
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Quote:
Originally Posted by wiredgeorge
John, PLEASE... go through the sugar analogy. It is hard to comprehend unless you know the maximum weight rating of the sack it goes into! Is the rating for the sack the same if you turn it upside down? What happens.... never mind, this will only stretch this discussion out farther and farther.
OP: 80 PSI. Use metal valve stems. Use an accurate air gauge. Use a TPMS system. That covered it as if it already hadn't been covered!
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Nah, just get another bag of jelly beans, put em in a bowl so you don't need to contemplate the bag, sit on the front porch and enjoy. Life's too short for explanations.....
__________________
John
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
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07-19-2022, 10:05 AM
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#35
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Senior Member
Join Date: Jan 2021
Location: USA
Posts: 278
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[QUOTE=wiredgeorge;509732
OP: 80 PSI. Use metal valve stems. Use an accurate air gauge. Use a TPMS system. That covered it as if it already hadn't been covered!
[/QUOTE]
Well for now it has the ½ brass stems, which are rated to 100PSI and no TPMS. Maybe I'll add those later this Summer, or for next year. I do have a good air gauge though.
I was inflated to only 60PSI with the D rated tires for the trip we just took, maybe that's why the belt broke and I got a flat in the first place!
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07-19-2022, 10:15 AM
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#36
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Senior Member
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
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Quote:
Originally Posted by hawghauler
Yep and it says 80 psi on the sidewalk so less than 80psi constitutes under inflation
Quit playing word games to make yourself feel more intelligent than another
|
The 80 PSI molded on the tire sidewall is not a recommendation. It's a factual statement from its manufacturer that it can provide its maximum load capacity (also molded on the tire sidewall) at 80 PSI.
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07-19-2022, 12:38 PM
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#37
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Gone Traveling
Join Date: Mar 2022
Location: Las Vegas
Posts: 20
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Quote:
Originally Posted by JRTJH
The below listed specs do not include the "magic of deducting tongue weight to get lighter axle weight"... Many people will argue that the axles don't carry the weight that's on the tongue, but just as many will ask, "What happens when you hit a pothole or a bump in the road or a railroad crossing and the axles bounce? Doesn't that increase the "load" on the axles" during that event?".....
Anyway:
Specs on the trailer:
empty weight: 3405
Cargo cap: 1295
GVWR: 4700
Tires: 2830 @80 PSI x2 = 5660 @80 PSI load capacity
5660-4700 = 960 remaining capacity.
Recommendations are for tire "reserve capacity" of 15% above rated weight
15% of 4700 is 705, so essentially, having 960 pounds of reserve capacity at 80 PSI is only 255 pounds more than "minimum"....
Or, to look at it as "individual tire capacity" at 80 PSI you're only 127.5 pounds "over the minimum".....
Do you really want to "air down those tires on a single axle trailer" ?????
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07-19-2022, 01:19 PM
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#38
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Senior Member
Join Date: Nov 2017
Location: Mico, TX
Posts: 7,447
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Quote:
Originally Posted by Old_Stevenick
Well for now it has the ½ brass stems, which are rated to 100PSI and no TPMS. Maybe I'll add those later this Summer, or for next year. I do have a good air gauge though.
I was inflated to only 60PSI with the D rated tires for the trip we just took, maybe that's why the belt broke and I got a flat in the first place!
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Perhaps glance through the numerous threads where people are trying to figure out how to repair the liners and skirting on their trailer. Once a tire blows out, where does the explosion go? I know the owner will be going to the bank to take out a 2nd mortgage to fix the mess. I think a single axle with a blow out would be just that much more interesting.
__________________
wiredgeorge Mico TX
2006 F350 CC 4WD 6.0L
2002 Keystone Cougar 278
2006 GL1800 Roadsmith Trike
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07-19-2022, 01:53 PM
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#39
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Senior Member
Join Date: Jan 2021
Location: USA
Posts: 278
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We were going maybe 65 and noticed it felt weird, pulled over. No explosion, no tipping over - not that "interesting" as you said a single axle blowout would be.
Multiple strands of metal sticking out through the tire (belt) totally flat. No explosion.
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07-19-2022, 05:12 PM
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#40
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Senior Member
Join Date: Jan 2021
Location: USA
Posts: 278
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Got this email from Keystone today. Covering their bases I guess.
Good Evening,
Thank you for contacting keystone RV. In regards to your email, below is what information I have found on your tire/wheels that should help with this inquiry.
Tire pressure - 65
Rim size: 15x6
Tire rating: 2540
Rim Rating: 2830.
Tire size: ST225/75R15D
We would not recommend changing any of these or going lower/higher as it could result in damges to the unit. If you do decide to change anything we would recommend that you have a Keystone authorized dealer or a tire center do this for you to ensure it is safe for the unit.
Thank you,
Gabriella Mahony
Digital Communications Agent
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