14 ply trailer tire at 90 psi
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From: Manitoba
14 ply trailer tire at 90 psi
I have a Heartland toy hauler camper 7000 lb axles. I purchased new 14 ply trailer tires which will hold 110 lb PSI. The tire dealer told me not to go over 80 lb PSI as the rims will split. He told me to run the tires at about 90 lb and I should be good. I wish he would have told me that before I purchase the tires. Maybe my best bet is to get steel rims now. Any ideas if 90 lb PSI will hurt the 14 ply tire. I scaled my truck and trailer after loading my two Harleys and I am right at the limit for the 7,000 lb axles.
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Joined: Aug 2002
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From: Castle Rock, CO
Well I see some conflicting information as you did 80psi rims 90+psi tires. Obviously new wheels with adequate pressure ratings will solve your problem.
To check the tires you can look up the load inflation table for that tire and see what pressure it takes to carry "X" weight. If the load inflation table shows you can carry the weight at 80 psi then you would be good. Many folks will add some psi above and beyond what the table calls for as an additional safety cushion or to compensate for uneven weight distribution Ie they have been able to weigh side to side or individual wheels. Tires need to be the same psi on an axle so if you know one side is say 500lbs heavier than the other use the higher weight for all tires on that axle. On a trailer with dual or triple axles I would use the same psi on all the tires. Always round up on the weight as it will be doubtful that they will have your specific weight listed on the chart.. You really do want to weigh the trailer loaded as you normally travel to get the proper weight. Don't just go by the axle rating. if your scale ticket says 14000 for trailer weight and assuming you have two axles and 4 tires 14000/4 = 3500 lbs per tire. Look up your tire at that weight (well 3500 is not a listed weight so round up to the next one which is 3640lbs and see what the psi is at that point you may want to ask yourself am I comfortable at that psi or should I go up 5 or 10 psi as an additional safety cushion or you know your trailers weight is not evenly distributed.
Below is a load inflation table just as an example, it is not for your tires as I have no idea what tires you are running
https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf
You will see that it lists tire size down one side and PSI across the top and the various weight ratings in the table itself. so start with the proper table, find your tire size then go across until you find your weight then go up to see the psi needed for that weight, (some tables are based on axle weight not individual tires however it will state that if that is the case)
Some people will say use max pressure listed on the sidewall of the tire which is fine, or to use the pressure listed on the trailers tire placard (which does not work for you at all as the tire placard on the trailer is for that specific size tire and load rating of that tire that came on the trailer and yours are not so it is meaningless). I am a believer in using the load inflation tables, the tire manufacturers know their tires better than the rv manufacturer, the government rules or the local tire jockey at discount tire. They created the load inflation tables for a reason and that is to properly inflate the tire for a given load. That is the place to start then if you feel it needs to be higher due to your personal wants, needs or situation then by all means do it. An example my tire placard on my fifth wheel states 80 psi I changed tire size and went up one size and changed from 15 inch to 16 inch wheels. According to the load inflation table I can run the same weight on the new size tire/wheel at 20 less psi and still have a bit higher weight rating than previously. My trailer rides better now at the lower psi. That is not why I changed them but it was gravy so to speak.
On edit I would add that on the load inflation table if the weight box is blank for a given psi don't use it it is below the recommended minimum psi for that tire
To check the tires you can look up the load inflation table for that tire and see what pressure it takes to carry "X" weight. If the load inflation table shows you can carry the weight at 80 psi then you would be good. Many folks will add some psi above and beyond what the table calls for as an additional safety cushion or to compensate for uneven weight distribution Ie they have been able to weigh side to side or individual wheels. Tires need to be the same psi on an axle so if you know one side is say 500lbs heavier than the other use the higher weight for all tires on that axle. On a trailer with dual or triple axles I would use the same psi on all the tires. Always round up on the weight as it will be doubtful that they will have your specific weight listed on the chart.. You really do want to weigh the trailer loaded as you normally travel to get the proper weight. Don't just go by the axle rating. if your scale ticket says 14000 for trailer weight and assuming you have two axles and 4 tires 14000/4 = 3500 lbs per tire. Look up your tire at that weight (well 3500 is not a listed weight so round up to the next one which is 3640lbs and see what the psi is at that point you may want to ask yourself am I comfortable at that psi or should I go up 5 or 10 psi as an additional safety cushion or you know your trailers weight is not evenly distributed.
Below is a load inflation table just as an example, it is not for your tires as I have no idea what tires you are running
https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf
You will see that it lists tire size down one side and PSI across the top and the various weight ratings in the table itself. so start with the proper table, find your tire size then go across until you find your weight then go up to see the psi needed for that weight, (some tables are based on axle weight not individual tires however it will state that if that is the case)
Some people will say use max pressure listed on the sidewall of the tire which is fine, or to use the pressure listed on the trailers tire placard (which does not work for you at all as the tire placard on the trailer is for that specific size tire and load rating of that tire that came on the trailer and yours are not so it is meaningless). I am a believer in using the load inflation tables, the tire manufacturers know their tires better than the rv manufacturer, the government rules or the local tire jockey at discount tire. They created the load inflation tables for a reason and that is to properly inflate the tire for a given load. That is the place to start then if you feel it needs to be higher due to your personal wants, needs or situation then by all means do it. An example my tire placard on my fifth wheel states 80 psi I changed tire size and went up one size and changed from 15 inch to 16 inch wheels. According to the load inflation table I can run the same weight on the new size tire/wheel at 20 less psi and still have a bit higher weight rating than previously. My trailer rides better now at the lower psi. That is not why I changed them but it was gravy so to speak.
On edit I would add that on the load inflation table if the weight box is blank for a given psi don't use it it is below the recommended minimum psi for that tire
Last edited by BarryG; Jan 12, 2023 at 10:40 AM. Reason: additional info
...Ben
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