Another tire question

[indy roadrunner]

For those who have changed from ST to LT tires will LT235/85/R16E fit on the 3400 or do I have to go to a LT245/75/R16?
I am looking at BF Goodrich Commercial T/A's. Big difference in price between these two tires at Discount Tire. The LT235 is $138 and the LT245 is $171.

[LonnieB]

The LT235/85R16E will fit. I have installed them on several 3400 Montanas, as well as my 3000 and others. They are 1.6 inches taller than the LT245/75R16E's and about 1.9 inches taller than the original ST235/80R16E's. The max load is the same (3042 pounds at 80 psi) on both the LT235 and the LT245. The LT245 is .30 wider than the LT235.

[indy roadrunner]

Thanks bunch Lonnie and also for your help with the PM's. I guess I am one of the few lucky ones as I bought my 3400 in April of 06 and I had my first Mission tire go bad with some evidence of belt separation so I went to the expert LonnieB for answers. Going to replace all 4 so if I can copy some else's phrase - don't have to worry about the MAY BANG tires.

[KTManiac]

quote:Originally posted by LonnieB

The LT235/85R16E will fit. I have installed them on several 3400 Montanas, as well as my 3000 and others. They are 1.6 inches taller than the LT245/75R16E's and about 1.9 inches taller than the original ST235/80R16E's. The max load is the same (3042 pounds at 80 psi) on both the LT235 and the LT245. The LT245 is .30 wider than the LT235.

So, are the "ST" rated tires for trailers all a bunch of hooey? I thought that they were specially designed for the high side loads placed on them as a result of tight turning with tandem axles, and thinner tread depth for cooler running, etc., etc.

[washley1]

My story is I have a new 09 Big Sky 365 REQ. It came with ST's, Carlyles, made in China. Last week, with only about 2000 miles on them, one blew. As far as I know, pressure was OK, had only been on the road for 30 minutes, and the explosion did about $1500 in damage. All I read now on the net is how bad those tires are. I'll be calling Keystone on Monday to find out why they put that crap on a rig that listed at over $90K! I am wondering now about LT's. Any thoughts on ratings, etc? My wet weight is about 19000, and I'd like to be able to sustain 70mph on the interstate. My F350 diesel dually has E rated tires; should I go with that on the trailer?

[indy roadrunner]

Ktmaniac do a search and title it LT tires for last 120 days. This is a nice thread addressing the subject of LT vs ST tires from those that has been or in the tire business.
Washly 1 welcome to the forum and sorry you had such bad luck right out of the gate. I think you will find not only on this forum but another popular RV forum that chinese ST tires do not have a very good track record. A lot of people dumped those tires right from the get - go. Why does any trailer manufacture use these tires - can we say lowest bidder, or better profit margins? Who knows I have been very lucky with mine having for 3 years but I only weekend camp and once a year vacation so I do not have the miles that others have.

[LonnieB]

quote:Originally posted by KTManiac

So, are the "ST" rated tires for trailers all a bunch of hooey? I thought that they were specially designed for the high side loads placed on them as a result of tight turning with tandem axles, and thinner tread depth for cooler running, etc., etc.

ST stands for Special Trailer and yes, they were designed to withstand the stresses and strains of trailer use. The problem is, they don't seem to do it very well. I sell and install lots of tires on lots of trailers and I see many more problems with the ST rated ones than the LT rated ones. To be fair, I have to say it's not always the fault of the tire. Sometimes it's operator error, as in overloading, underinflating, or traveling above the 65 mph speed rating.

quote:Originally posted by washley1

My story is I have a new 09 Big Sky 365 REQ. It came with ST's, Carlyles, made in China. Last week, with only about 2000 miles on them, one blew. As far as I know, pressure was OK, had only been on the road for 30 minutes, and the explosion did about $1500 in damage. All I read now on the net is how bad those tires are. I'll be calling Keystone on Monday to find out why they put that crap on a rig that listed at over $90K! I am wondering now about LT's. Any thoughts on ratings, etc? My wet weight is about 19000, and I'd like to be able to sustain 70mph on the interstate. My F350 diesel dually has E rated tires; should I go with that on the trailer?

Have you weighed your trailer? If I am thinking right, about 20% of that 19000 pounds rests on the tow vehicle, so about 15200 pounds would be on the tires of the trailer. That would be 3800 pounds per tire, quite a lot more than the load range E tire can handle. A load range G tire at 110 psi would also be overloaded a little. As far as speed goes, the Goodyear G614 load range G is rated for 70 mph max. All ST tires are rated at 65 mph max.

[washley1]

Thanks for all the feedback, but now I'm REALLY confused--it sounds like there are NO tires rated to carry this rig. You say you are in the tire business. What would you go with? I have always been partial to Michelins, but I want to be safe.

[bigmurf]

Are you sure on the 19000 lbs?

[KTManiac]

quote:Originally posted by washley1

....My wet weight is about 19000, and I'd like to be able to sustain 70mph on the interstate. My F350 diesel dually has E rated tires; should I go with that on the trailer?

The Big Sky 365 REQ is maxed out at around 16,450 lbs according to the specs on the website. If you are truly running it at 19,000 lbs, you are grossly over weight on the carrying capacity ...to the tune of a ton and a quarter! If your figures are correct, you are hauling over 3 tons of cargo! You would have to have a triple axle to haul that much weight.

I suggest that you actually weigh your rig when loaded, instead of just guessing. :-/

[LonnieB]

quote:Originally posted by bigmurf.

Are you sure on the 19000 lbs?

I have to ask the same question. Have you actually weighed the trailer?

quote:Originally posted by washley1.

Thanks for all the feedback, but now I'm REALLY confused--it sounds like there are NO tires rated to carry this rig. You say you are in the tire business. What would you go with? I have always been partial to Michelins, but I want to be safe.

Yes I am in the tire business and I would really like to help you out, but I need an accurate weight in order to make any kind of recommendation. (That almost sounded like, I'm from the Government and I'm here to help ).
On the left front corner of your trailer there is a sticker that lists the weight ratings of the trailer. If even one of these ratings is being exceeded, you are operating outside the safe zone. I believe your Big Sky has 7000 pound axles under it, so you are limited to 14000 pounds on the two axles combined. That leaves 5000 pounds in the bed of your truck if the trailer weighs 19000 pounds.
I hope I haven't made this more confusing than it already was. If so, maybe someone can help me clarify it.

[washley1]

OK, gang I goofed!! The trailer dry weighs 12700 according to the web site, with 3750 for storage, equals 16450. I probably have no where near 3750 in stored stuff (YET!). The stated hitch weight is 2450, leaving 14000 for the 4 wheels, or 3500 each. Where do I go from here? And thanks in advance for all the help!

[indy roadrunner]

Washley1 let me jump in here for just a quick note. Being new to the forum you will find that we have several "specialist" we rely on to assist with maintaining our Montana's. From time to time we utilize these folks specialities at no cost - they are just glad to help. LonnieB is our tire specialist, MIMF2 is our frame and slide specialist, Ozz is our modification specialist and we have many more and I hope I don't offend any one by not mentioning here as there are several. Another thing I would highly like to recommend is trying to make the Fall rally in Goshen as you will have an opportunity to meet some of these "specialist" along with vendors of products that go in the manufacture of these units.
Good luck with the tire selection as it does put a bite into the budget and keep posting here so others can jump in with their expertise.

[LonnieB]

Ok washley1, that helps a bunch.

The LT235/85R16 load range E (10 ply) is only rated for 3042 pounds at 80 psi, as is the LT245/75R16 load range E (10 ply). Not enough to carry the 14000 pounds your axles are capable of. In order to get the full carrying capacity your Big Sky is capable of, you will have to use a G (14 ply) rated tire which can carry 3750 pounds at 110 psi. Unfortinately there are only a couple of brands of these available and Michelin isn't one of them. The Goodyear LT235/85R16RST G614 is the most popular and they are rated for 70 mph. Another one I have had good luck with is the Hankook 7.50R16 F19 load range G.

[Glenn and Lorraine]

Lonnie, Just how available is the Hankook nationwide and how is the pricing in comparision to the G614??
If and when I need to again replace the 4 trailer tires I am considering going to G rated. I would not want to put on a tire that is not readily available where ever I may be traveling in the USofA.

[LonnieB]

quote:By Glenn and Lorraine

Lonnie, Just how available is the Hankook nationwide and how is the pricing in comparision to the G614??
If and when I need to again replace the 4 trailer tires I am considering going to G rated. I would not want to put on a tire that is not readily available where ever I may be traveling in the USofA.

That's a very good question Glenn. The Hankook is a popular tire here in the Southwest and the West, but I don't know about the rest of the USA. At the time of this posting I have 10 in stock and the distributor I get them from (American Tire Distributors) has 87 in stock in Lubbock, Tx. and no telling how many more in their other warehouses across the USA.

Price for the Hankook will run around $170.00 vs $275.00 for the G614. Prices will vary of course in different parts of the country, but the difference between the two should be fairly consistent.

Monday, I will do some further research to see how available they are nationwide.

[washley1]

Well, I goofed! Trailer dry weighs in at 12700, has a capacity of 3750 cargo, for a total of 16450. So far, I do not have that much cargo. Less a hitch weight of 2450, that leaves me with 14,000 pounds for the 4 tires, or 3500 each. That is still above what I have seen so far. According to the chart on the MOC page, the best I can get to is 3415 with a LT265/75R16E. Will those do the trick? Will they fit this rig? Would I be safe at 70 MPH? Thanks in advance!!

[washley1]

Goofed again by double posting!! Lonnie, my question for the guys at Keystone is now why would they put a tire on the rig not rated to carry the load? I certainly didn't know enough to ask from the outset, I had to assume they knew what they were doing! If I go to the G rated at 110PSI, will my stock rims handle the load?

As far as the rally in Goshen, that may be a target now, but my first concerns are making this rig safe for a swing from here in FLA up to Nova Scotia and back in June. You guys are helping a lot, and it is appreciated!

[LonnieB]

Look closely at the sidewall of your tires for the MAX LOAD information. In very small letters you will see the ST235/80R16 load range E is rated for a maximum load of 3500 pounds at 80 psi. So, to answer your question, Keystone DID install tires of the proper load rating on these trailers, inferior quality perhaps, but with the proper ratings. If you call Keystone looking for answers to questions about tires, they will most likely tell you that DOT regulations require them to use the ST rated tires. Wheather this is true or not, I don't know, but it wouldn't surprise me. There are a lot of government regulations that look good on the books, but are complete failures in the real world. This is just my opinion of course .
As for your wheels being able to handle 110 psi, you will have to remove one and look at the back side to find the rating.

[washley1]

As soon as the repair shop puts my rig back together, I will take a look. But if that's the case, why do the charts have a lower max?