Jim is right on ST tires. Look at the casing of one and it will say something like "for trailer use only". There is a reason for that statement branded on the sidewall and it not because is better then an LT or a P series tire. They are simply the cheapest tire that that can be installed on the trailer when it is built.
The last thing I will say is I will never by any RV with ST tires or 15" wheels again. It will be either 16" or 17.5".
I jut made the switch to 16" aluminm wheels with BFGoodrich Commercial T/A all season LT tires for my fiver. Despite 6k trouble free miles on 15" Marathons, I felt I had been lucky and did not want to continue to push it. I have read countless pages of posts on this forum s well as others about ST tires AND Marathons. I decided I'd rather spend the $1200 to upgrade to a tire wheel combo I have nothing bad about. I don't care how well Goodyear has stood behind their tires. THEY SHOULD. Their tires are not worth the possible headaches, worry, liability, and possible injury or death to me. I have my 15" wheels and Marathons in the classifieds now and can't wait to get them out of my garage. If there are any Marathon fans out there, let me know. I've got some for sale! PCM
JIMNLIN wrote: --Snip-- Trailer tires (ST) don't carry passangers. If they did the tire industry would have fixed the problem many many years ago. Its really a shame that our RV manufactors and some lighter made non RV type of trailer still mount any brand ST tire on 5k-6k axles with small 15" wheels.
The fix is doing what some upper line of RV trailers and many brands of commercial grade of flatdeck trailers have done and that is go to a good brand of 16" LT tire that is recommended for heavy trailer use. Suspension mod work may be necessary for this upgrade but will eliminate ST type of tire problems.
Jim
JMO, but, I believe the trouble with ST tires lies with the original specifications of the tire.
I don't think the ST tire is DOT rated for passenger carry while the LT tire is.
Because the ST tire is not made to the same stringent specifications as the LT tire, we will have more problems with them. In other words the ST tire is a cheaper tire than the LT tire, it's too bad we can't get LT tires in all the same sizes as you can the ST tire.
Right now I'm running Goodyear G114 tires in 225/75R17.5 LRH that I upgraded from Goodyear G614 tires in 235/85R16 LRG on our 5th wheel. The 17.5" tires are actually 1/4" smaller in OD than the 16" tires are.
I think there are two reasons some people have tire problems.
One is that most of the ST tires are speed rated at 62 MPH and the other is that some people will not weigh their set ups and wind up overloading the tires.
Most people want to keep up with traffic when towing and will drive between 65 and 75 or even faster, and do so for hours at a time. Most ST tires are only speed rated for 62 MPH max. and could blow from excessive heat when driving at 65-75.
Others will load their trailers with all the "stuff" they want to take and because they don't weigh their set ups, wind up overloading the tires, this could also happen if you are using LT tires.
I also think you should switch from the ST tire to the LT tire IF you can find one in your size.
The LT tire is rated at 75 MPH and gives a greater safety margin when driving at higher speeds.
Most of the heavier trailers will come from the manufacturer with LT tires that are speed rated at 75 MPH.
I still keep the speed at 62 or below but the extra safety margin of the LT tire is nice to have.
Both my last two Newmars came from the factory with LT Goodyear tires and we have had no tire issues at all.
If you want to find out the who, what, when & where about your tires, go to this site and follow the directions, you can find out where your tires were made.
The last four numbers in the DOT code (only on one side of the tire) is the week and year the tires were made, (2207 would be the 22nd week of 2007) If you have a three digit code the tires were made before 2000.
This is JMO and only costs what you paid for it.
1990 6500 Chevy Kodiak, 8.3L Cummins 450 HP
6sp Allison 3060, 3.70 R/A Home Made Air Ride
2006 Newmar Cypress, Pics of '93 Mountain Aire
I put Denman tires (225x15) on my former 5th wheel trailer two years ago based on good reviews I saw on this and other RV sites. I sold the trailer to a friend last Sept. He came by a week ago from a 4k mile trip. The Denmans still look good after more than 10k miles overall with little tread wear and no visible cracking or problems. Because of availability, two of the tires are D and two are E rated. I could not see any difference in performance with either. They may not be perfect, but I would trust Denman trailer tires based on experience.
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