5th wheel tire pressures
Thread Starter
|
Junior User
Joined: Dec 2001
Posts: 79
Likes: 0
From: 22 acres of country
5th wheel tire pressures
I have recently purchased a 30 foot tandem axel 5th wheel with a slight mis-match of tires.
All four tires are Good Year Marathon ST 225/75R15. One of the four is Load Range D rated for 2540 lbs @ 65 psi and the other three are Load Range C rated for 2150 lbs @ 50 psi.
My question is what tire pressure should I use? Three @ 50 and one @ 65? Also I recently found out that tires inflated above 65 psi should have "high pressure" valve stems. Would you bother changing on the one tire or just forget it?
All four tires are Good Year Marathon ST 225/75R15. One of the four is Load Range D rated for 2540 lbs @ 65 psi and the other three are Load Range C rated for 2150 lbs @ 50 psi.
My question is what tire pressure should I use? Three @ 50 and one @ 65? Also I recently found out that tires inflated above 65 psi should have "high pressure" valve stems. Would you bother changing on the one tire or just forget it?
Posting Guru
Joined: Jul 2001
Posts: 1,914
Likes: 1
5th wheel tire pressures
The tires are limited by their carring capacity. The load range D buys you nothing if it is working alone. Look at the weight limit of your trailer,if it is over 8600 lbs, the tires are in overload. I would think a 30 ft would be closer to 10,000 lbs LOADED. Sounds like it needs new load range D tires on all wheels.
Thread Starter
|
Junior User
Joined: Dec 2001
Posts: 79
Likes: 0
From: 22 acres of country
5th wheel tire pressures
Well you are right about the total weight thing but my question is concerning tire pressures. Would you run all four at 50 psi or three at 50 and one at 65?
Elder User
Joined: Jun 2001
Posts: 775
Likes: 0
From: Northern Va
5th wheel tire pressures
I think what Flash is saying it to replace the C load rated tires with D load rated tires of the same type and brand you already have. If you do that the pressure AND overload problem goes away.
Overloaded tires create a safety issue for you and whomever is beside/behind you when the tire lets loose.
This is not a flame, please take it as useful advise from someone who has seen the results of overloaded tires.
Overloaded tires create a safety issue for you and whomever is beside/behind you when the tire lets loose.
This is not a flame, please take it as useful advise from someone who has seen the results of overloaded tires.
Postmaster
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
5th wheel tire pressures
Trailer Life Magazine has an article about trailer tires in the Sept or was it Aug issue. Their recommendation was not to under inflate any tire by more than 10% or so. For your 65psi tire that means you should not go less than about 58psi cold. I would recommend going to max on all the C ratings and go with about 60psi or more on the D. Of course you won't get the full benefits due to the mix. Also you might have size differences which may cause strange handling. I would try to match the tires, and igo with a heavier rating if I was near max on the C's.
Good Luck,
Jim Henderson
Good Luck,
Jim Henderson
Thread Starter
|
Junior User
Joined: Dec 2001
Posts: 79
Likes: 0
From: 22 acres of country
5th wheel tire pressures
Thanks for the advice. I am new at this towing heavy trailer stuff so will likely be back with more questions later.
I appreciate that you folks take your time to answer.
I appreciate that you folks take your time to answer.
Senior User
Joined: May 2002
Posts: 484
Likes: 1
From: Garden Grove USA
5th wheel tire pressures
The article in Trailer Life mag was a good one, but it DID NOT say that you can vary any tire pressure by 10%. Trailer tires are designed to run at the stated pressure regardless of the weight. DO NOT over or underinflate trailer tires. The only tires that can handle a pressure varition is light truck (LT) tires. So most tire on your pickup, if they have the LT designation can handle a 10% pressure variation depending on loads.
I too have experience with overloaded tires going Kaboom! Not fun. Before you do anything replace the tires with a matching set with the correct rating, if not overrating for your trailer wieght.
If you bought the trailer new from a dealer, I would insist that the dealer replace the tires with a safe set, or at least reimburse you for part of the cost.
Good luck...
I too have experience with overloaded tires going Kaboom! Not fun. Before you do anything replace the tires with a matching set with the correct rating, if not overrating for your trailer wieght.
If you bought the trailer new from a dealer, I would insist that the dealer replace the tires with a safe set, or at least reimburse you for part of the cost.
Good luck...
Trending Topics
Senior User
Joined: Jul 2002
Posts: 267
Likes: 0
From: baltimore USA
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
New User
Joined: Oct 2002
Posts: 1
Likes: 0
5th wheel tire pressures
I've been towing 5ers for years and you wouldn't beleive the damage a flapping tread can do to a camper before you can get stopped. For peace of mind I would get 4 new tires and use the best one for a spare.
Mike
Happy Camping...
Mike
Happy Camping...
Posting Guru
Joined: May 2002
Posts: 1,673
Likes: 0
From: Chicago Area
5th wheel tire pressures
It is really the air pressure which supports the load. This is obvious if you think about how much an uninflated tire can support (nothing). "D" rated tires are stronger to contain higher air pressure which in turn supports greater weight.
I believe the physical dimensions are the same, so I would be reluctant to vary the tire pressure, which would change the height and effective rolling diameter. Just run all tires at the maximum "C" pressure and make all load calculations as if they were "C" rated. If this indicates overload, replace them all.
This half-a**ed set-up should prompt you to check everything else about the trailer!
MrBSS
I believe the physical dimensions are the same, so I would be reluctant to vary the tire pressure, which would change the height and effective rolling diameter. Just run all tires at the maximum "C" pressure and make all load calculations as if they were "C" rated. If this indicates overload, replace them all.
This half-a**ed set-up should prompt you to check everything else about the trailer!
MrBSS
Thread Starter
|
Junior User
Joined: Dec 2001
Posts: 79
Likes: 0
From: 22 acres of country
5th wheel tire pressures
The mystery to me is why Goodyear would change load ratings on identical size tires with identical tread pattern. Yes it would be considered an upgrade but in my considerable years, I have never encountered this before.
Posting Guru
Joined: May 2002
Posts: 1,673
Likes: 0
From: Chicago Area
5th wheel tire pressures
Actually, this is fairly common with trailer tires. I have also seen it on trucks and SUV's, where the manufacturer wants to stay with the same diameter but needs a greater load rating.
MrBSS
MrBSS
Thread
Thread Starter
Forum
Replies
Last Post
whiteaddiction
1994.5 - 1997 7.3L Power Stroke Diesel
2
Feb 5, 2009 03:38 PM
big poppa
1999 - 2003 7.3L Power Stroke Diesel
12
Jun 10, 2008 11:37 PM