Trailer Tire Facts

[Ahab]

Originally Posted by 48Bob

Driftless - Our new 2010 Dodge Ram 1500 came with LT tires on it. In the past, I have always had sidewall problems with P metric tires on pickups. The sidewalls are thinner and more prone to puncture that the LT tires. But then again, this might be a function of my actually using my pickups off of the pavement! We do a lot of miles on gravel and dirt roads, both with and without a trailer of some type. Aired up to the proper presssure, I don't notice any difference in ride between the P and LT tires. But then again, it is a pickup. I have also towed a very heavy steel four horse trailer with LT tires on it for many miles over all types of roads with virtually no tire problems. That is one reason that I changed the 15" ST 's on our 20' single axle Safari SE to 16" LT tires. Just my two cents worth.

Hmmm, so you are a tire engineer?

[TouringDan]

Arrowstream

Thanks for posting the load/inflation information, but I have some comments/questions on the tables.

1. The Michelin tables are not very useful for Airstream trailer owners since the smallest wheel diameter listed is 16". Most Airstreams are 15".

2. There are letters in parenthesis next to the inflation pressures that are in bold print. These range from B to G. What does this mean?

3. The table lists the load capacity for various inflation pressures. Do you match the load that the tire is carrying to the inflation pressure? For example, if my trailer has ST205/75R15 tires and my trailer weighs 4,280# then the tire load is only 1,070#. So do I only inflate my tires to 20 psig? Or do I inflate to 50 psig where the load capacity is 1820(C) and have some margin? I am confused.

Seems like there is a lot of conflicting information from the folks that should know: Airstream, Tire distributors and tire manufacturers.

Dan

[xonvldz]

andy,thanks for clarifying my situation.i did the measurements and the tires between the d and e rated are the same size and width.will be taking a trip to oc md soon,and will keep an eye on any sway.if need be ill replace the front axle with the e rated tires before going to fla in the fall.

[halimer]

DSRTGRLS,

I rotate my spare. Also, I my Dexter Axle manual it says you can use ST or LT tires so long as them are the same or greater LR for the axle.

Mark

[Arrowstream]

Hello Dan, the B thru G lettering would be for footnotes (that weren't included in the pdf). I guess I'll have to look further to see what they meant. The pressures given were the minimum required to carry the load, not the ideal pressure. Over inflation will give you a harder ride and less traction. In addition to inflating the tires to the recommended pressure by the vehicle manufacturer, another check that I've done is to wet the tire, roll forward and check the footprint.

[48Bob]

Ahab, nope, I am not an engineer, just a poor country hick that has towed a variety of trailers lots of miles on lots of bad roads. Again, it is just my 2 cents worth, but I have had very good luck using LT tires on my trailers and tow vehicles.

[dznf0g]

Spoke to Chris on this subject yestrday. I asked if he could clear up all this tire confusion for me. He smiled and said "no". We then had a discussion.

AS offers 15" LRD, 15" LRE, and 16" LT as, not a recommendation, but a customer offering. He would not recomend one over the other, but I asked what he would do if he had my trailer. He replied, 15"LRE at 65 PSI. (I'm at 8500 pounds, loaded, hitched and ready to go). Guess I'll move up from 60psi to 65.

[streamair]

Originally Posted by dznf0g

Spoke to Chris on this subject yestrday. I asked if he could clear up all this tire confusion for me. He smiled and said "no". We then had a discussion.

AS offers 15" LRD, 15" LRE, and 16" LT as, not a recommendation, but a customer offering. He would not recomend one over the other, but I asked what he would do if he had my trailer. He replied, 15"LRE at 65 PSI. (I'm at 8500 pounds, loaded, hitched and ready to go). Guess I'll move up from 60psi to 65.

15" LRE is your best bet. Good Choice.

[Cracker]

As I recall - without having a Goodyear chart in front of me - one of the footnotes states that Goodyear does not recommend inflating to less than 45 psi regardless of the load. This was specifically for the Marathon ST tires. Theoretically, at 50 psi (Airstream Spec for my trailer) either the "C" or "D" tires carry 2,150 lbs x 4 = 8,600 lbs. With 900 lbs on my hitch, and very little load transmitted to the trailer tires with the equalizer bars, my trailer net axle weight is right at 7,400 lbs (---checked by scale but weight slip not handy right now.) That leaves a reserve of 1,200 lbs for a possible differential in load from side to side - or due to road conditions. I'm running "D" tires since my last change (5-years back) but still inflating to 50 psi. I'll put new Marathons on ("D") if I head south this winter - otherwise, I'll wait until next spring.