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Old 01-01-2014, 08:12 PM   #29
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Quote:
Originally Posted by Racklefratz View Post
I do not "inflate to the max pressure on the sidewall, and made a conscious decision not to do that.

Max inflation pressure guarantees the trailer frame and contents will get the harshest ride possible. My Goodyear G114 tires are so far above any load my trailer will ever place on them I inflate to the pressure from the tire loading chart from Goodyear that most closely matches loaded CAT scale weights. YMMV
Garbonz recommendation was for a ST E which is a 80 psi tire is excellent advice for several reasons and has nothing to do with a 110 psi rated tire your using.

Lots has been written about over tiring a trailer. Yes it happens mostly on RV trailers where the owner mistakenly thinks if 10-15 percent reserve capacity is good then 30-50 percent is even better.
This to ponder when selecting tires for a RV trailer ......

Quote:
rvsafety.com

Tire Load and Inflation Ratings

Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.
Quote:
Tireman9
rvtiresafety.com


The question of load capacity and Load Range gets asked a lot, so it seems to be a bit of a stumbling block for a number of RV owners. Here is an example:
"I need to replace the ST235/75R15 tires on my trailer. Currently have load range C tires which is sufficient for the maximum trailer weight when inflated to 50psi but allows almost no safety margin. I want to change to either load range D or E tires. My rims are only rated for 65 psi so if I went to the load range E tires I would only be able to inflate them to 65 psi. My question is this. Is there any advantage to a load range E tire used at 65 psi vs a load range D tire at 65 psi?"

Now just because he is asking about a 15" trailer application and considering a change from LR-C to LR-D it does not mean the general answer does not apply to others, even if they are considering a change from LR-G to LR-H on a Goodyear 295/75R22.5 Class-A tire.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

The answer to the question is;
He will gain a safety margin if he increases his inflation to 65psi with LR-D but if he stays at 65psi there is nothing further gained by going to LR-E as there is no difference in the capacity at 65psi.
The same thing would apply to the 22.5 example. When we look at the Goodyear tables we see that at 110psi both the LR-G and the LR-H are rated for 6,175# single or in dual application at 100psi they both are rated as 5,675#.

Special note: It is important that you look at the table on the web site of the manufacturer of your tires as not all companies give the exact same capacity number at every inflation level, even for the same size.
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Old 01-02-2014, 04:51 PM   #30
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Quote:
Originally Posted by Racklefratz View Post
I do not "inflate to the max pressure on the sidewall, and made a conscious decision not to do that.

Max inflation pressure guarantees the trailer frame and contents will get the harshest ride possible. My Goodyear G114 tires are so far above any load my trailer will ever place on them I inflate to the pressure from the tire loading chart from Goodyear that most closely matches loaded CAT scale weights. YMMV
When plus sizing your tires there is an industry standard to follow. Most tire retailers will have the procedure somewhere in their files for different tire designs/constructions.

New recommended tire pressure (s) are required and are set from the certified OE tires capacities. In other words, an OE tire providing 3420# of load capacity at a certified recommended tire pressure of 80 psi is the target figure to match with the replacement tires. That means to use a tire inflation chart for the replacement tires and use the amount of tire pressure necessary to provide a minimum of 3420# of load capacity in each tire. That becomes the new recommended tire pressure. Notations should be made in the trailer’s owner’s manual and an auxiliary tire placard should be mounted close to the OE tire placard to inform all others of the recommended tire pressures for the replacement tires.

When going to the scales to insure you’re not overloaded in any positions, the new recommended tire pressure can be increased but not lowered.

If you would like a more detailed explanation of the standards send me a PM and I’ll provide a reference.

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Old 01-03-2014, 08:23 AM   #31
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Quote:
Originally Posted by JIMNLIN View Post
Garbonz recommendation was for a ST E which is a 80 psi tire is excellent advice for several reasons and has nothing to do with a 110 psi rated tire your using.
The statement was "stay with ST tires and inflate to max" and there was no quote to indicate it was a reply to another post. I responded to that.
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Old 01-03-2014, 08:45 AM   #32
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Quote:
Originally Posted by FastEagle View Post
When plus sizing your tires there is an industry standard to follow. ... New recommended tire pressure (s) are required and are set from the certified OE tires capacities.
Duly noted.

However, I have little confidence in "OE tire capacities", of our trailer, at least, which came with Chinese "may-pop" tires. I happen to be painfully aware that it's not beneath many RV mfgrs to take "engineering shortcuts" and make compromises, often to facilitate using substandard equipment.

Case in point: Using the "OE published data", our prior Class A was designed such that, with only the two front seats occupied, we were at the designed front axle tire load LIMIT, with nothing else in the basement storage, filling the water tank, etc - so much for "OE tire capacities". This is the kind of OE "engineering" typical of many RVs, and a key factor that drove my decisions for the tires being discussed here.

My decisions on which tires to buy for our 5th wheel trailer, and how to inflate them, were made with an abundance of caution. Unlike some, I do not take it upon myself to give "instructions" on how they should be doing things, especially where safety is involved.

Thanks for your concern.
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Old 01-03-2014, 11:08 AM   #33
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This post concerns me. ST stands for "special trailer tires". They have larger cords, stiffer sidewalls, etc than LT (light duty tires). Why do people prefer LT tires on campers?
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Old 01-03-2014, 11:41 AM   #34
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Glennwest: very simple answer, read the forums and see all the problems with the ST tires, then notice how many have switched to LT tires and compare their problems to those still running ST tires. Very rare to hear of an LT tire problem while ST failures are a Dime a Dozen. But you do have to stay within the ratings of any tire. Because of our weight a typical LT tire would be out of the question so we went with the optional G614 but after weighing found we were pushing close to their limit so we've gone all the way to the 17.5 wheels and H tires.
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Old 01-03-2014, 01:03 PM   #35
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Well said.
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Old 01-03-2014, 01:08 PM   #36
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I had problems with the Goodyears ST on my DRV. They were 2 years old and we had no idea how they have been cared for. We replaced with new tires, the same. 0 probems. That was 2008. I have great service out of ST Goodyear
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Old 01-03-2014, 01:08 PM   #37
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All the tire failures I've had on our 5th wheels have been on "trailer only" tires - Goodyear Marathons and Goodyear G614 RSTs (technically, an LT235/85R-16G tire although labeled for trailer use only, which is effectively an ST tire). I've never failed a Michelin XPS Rib (an all-steel construction LT tire) or a 17.5" Michelin XTA as installed on our current 5th wheel. AFAIC, the proof is in the results, and I have no use for ST-labeled tires under a heavy 5th wheel.

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Old 01-03-2014, 01:15 PM   #38
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Those 614's is what I have. We came across scales just shy of 17,000# also. 0 problems. I personally think Goodyear just had a bad run of tires. They paid for 2 of them that failed on the original tires. i just replaced the rest. My Teton has Marathon's on it !!!!
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Old 01-03-2014, 01:17 PM   #39
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Goodyear paid for all my repairs due to failures and replaced the tires as well - 4 Marathons and 4 G614 RSTs. There comes a point, however, where I would rather not have a failure than have failures reimbursed - thus, my current tire selection based on my personal experience. It's worked out well for me - YMMV.

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Old 01-03-2014, 02:16 PM   #40
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I am very surprised that no one has questioned the op's given pin weight. Seems to be plenty lite compared to trailer weight.
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Old 01-03-2014, 02:40 PM   #41
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The trailer says its dry weight is 11650 with 2370 for loading which makes it 14020. The china bombs are 3520 (235/80-R16) a tire but I want to go with the LT tires the same size which are 3042. When computing the weight the tires are carrying the tire shop told me I don't use the 14020, rather subtract the hitch weight (2020) from the total and that's what is on the tires.
2020/11650 = 17.3%. Probably close for a "dry" trailer since most storage is ahead of the axles, meaning the percentage will climb as the trailer is loaded. The hitch weight is almost certainly based on the dry weight since I've very seldom seen an advertised hitch weight of a trailer loaded to its GVWR.

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Old 01-05-2014, 06:36 PM   #42
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We have a 2002 28' Lakota with "Master Track" trailer tires. The truck tires are 16" and the fifth tires are 15". So when I'm doing 65mph the trailer tires are at their limit of 65mph. Right?
Are 15" LT tires, E rated the answer?
Thank you all!
Matt
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