I have had so many problems with Good Year Marathon tires I am thinking about going to a Michelin LT 235 85R 16 tire to replace the ST235 80R 16 load range "E". When I check the load range on the Michelin tire it is 400 pounds less than the Good Year which is rated at 3,400 pounds. The Good Year tires are two years old and I am stuck in Williamsburg Virginia with four tires with tread separation and blisters and can not get home until I but tires.
My Montana weighs 13,000 pounds as it sets, so I need a tire that will carry that load. The tire dealer I am talking with is trying to sell me LT tires and I am concerned about them not being able to carry the load. Can somebody help me with good information?
2012 Ford King Ranch F-350 Crew Cab Diesel
2011 Montana 3580RL
Wife Sue
Pets: Rainbow Bridge: Old Fella, Levi, Charlie. Others Suzie, Peaches, Hobo, Mama, Izzie
Will an LT265/75R16E fit your trailer? If so...that might work. IIRC, those are good for ~3200lbs each.
How much is actually on the AXLES? (Trailer weight minus pin weight)
John and Elizabeth (Liz), with 3 nutty cats
My beloved St. Bernard, Marm, lost him 1/2/12
Current rig:
1992 International Genesis school bus conversion
Even though your rv weighs 13K around 25% of that is pin weight. I would look at some Firestone Transforce HT with a load range E. I have two friends with 5er's that are heavier than yours and they run the firestones with no issues. good luck
What axles fo you have? Probably 6000 pound? So all you need are tires with a load carrying capacity of 3000 pounds each. It is a no brainer. LT 235 85 R16. Michelin if you can justify about 1300 dollsrs. BF Goodrich Commercial TA for about 800 dollars.
Donn,Lorri,Max (The Rescued Lab)
Resident Know It All
donn0128 wrote: What axles fo you have? Probably 6000 pound? So all you need are tires with a load carrying capacity of 3000 pounds each. It is a no brainer. LT 235 85 R16. Michelin if you can justify about 1300 dollsrs. BF Goodrich Commercial TA for about 800 dollars.
The axles are Dexter rated at 6,000 pounds. I have a dealer that will come to our campsite and replace all four tires with Michelins LT235 85R 16 for less than $1,000.
I believe your Montana is on 7K axles and Keystone derated them to 6750 on the placard. You need to throw in your wallet and put Goodyear G614's on it. They are rated to 3750 each. Your have to check that your wheels are rated to 110 lbs. If not, you might as well install 17.5 rims and 215/75R17.5 LRH tires. That is what come OEM on a lot of larger trailers now. They have a diameter similar to your Marathons.
Somewhere in a Fifth Wheel - Where it does not Snow
Snow_King wrote: I believe your Montana is on 7K axles and Keystone derated them to 6750 on the placard. You need to throw in your wallet and put Goodyear G614's on it. They are rated to 3750 each. Your have to check that your wheels are rated to 110 lbs. If not, you might as well install 17.5 rims and 215/75R17.5 LRH tires. That is what come OEM on a lot of larger trailers now. They have a diameter similar to your Marathons.
You are correct. the spec card on the camper says the axles are rated at 6,750 pounds
I found this and copied it. Good Info about ST vs LT.
I copied and pasted this portion of a post by Mike Mitchell, NuWa (HitchHiker) CEO in a discussion regarding trailer tires on the NuWa Owner's Forum.
++++++++++++++++++++++++++++++++++++++++++++++++
"Read the following and learn from this RV.net fellows research. MIKE
As we banter about regarding tire types and loading, I believe that we are finally starting to understand a few important things.
I have asked many times for someone to explain how a ST tire can be rated to carry more weight than a LT tire in a similar size, without a good answer.
The answer lies in what is called reserve capacity. To quote from Trailer Parts Superstore and this same statement exist on just about every tire site:
HEAVY DUTY 'LT' TRUCK / TRAILER TIRES
'LT' signifies the tire is a "Light Truck/Trailer" series that can be used on trailers that are capable of carrying heavy cargo such as equipment trailers.
If a tire size begins with 'LT' it signifies the tire is a "Light Truck-metric" size that was designed to be used on trailers that are capable of carrying heavy cargo or tow vehicles. Tires branded with the "LT" designation are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.
So what is reserve capacity? It is capacity beyond the rating of the tire, capacity that is held in reserve. This reserve capacity comes from the heavy-duty sidewall of the LT type tires. LT's rank at the top of the list when we look at P, ST and LT tires.
Now I finally have an answer to how a ST tire can be rated to carry more weight than a LT tire of similar size.
The ratings of ST tires infringe into the reserve capacity of the tire. This is double bad, because the design of the ST gives us a tire with less reserve capacity to start with as it has a lighter sidewall to start with as most ST tires are much lighter than their LT counterparts.
To quote one tire site:
"Put a different way, the load carrying capacity of an ST tire is 20% greater than an LT tire. Since durability is strictly a long term issue - and the results of a tire failure on a trailer are much less life threatening than on a truck - the folks that set up these load / inflation pressure relationships allow a greater......ah......let's call it load intensity."
There it is in print to be read. They make a calculated decision to give the ST tire a higher load rating because a failure is less life threatening.
I have on a number of occasions pointed out the weight difference between the different tires and have been told that does not matter. Well it does matter. The rubber in the average tire only makes up around 40 some percent of its weight, the rest is in the steel belts, gum strips, steel beads, and the carcass plies. The remaining 60 or so percent of the stuff in a tire is what builds in the reserve capacity.
So to review again, here are some weights:
1. Michelin XPS RIB LT235/85R16 LRE (rated to 3042lbs) Weight 55.41
2. Goodyear G614 LT235/85R16 LRG (rated to 3750lbs) Weight 57.5
3. Bridgestone Duravis R250 LT235/85R16 LRE(rated to 3042lbs) Weight 60
4. BFG Commercial TA LT235/85R16 LRE(rated to 3042lbs) Weight 44.44
5. Uniroyal Laredo HD/H LT235/85R16 LRE(rated to 3042lbs) Weight 44.44
6. GY Marathon ST235/80R16 LRE(rated to 3420lbs) Weight 35.4
So which tires on the list have the most reserve capacity? Well that is not a completely simple answer, as one of the tires is a G rate 110 lb tire and the rest are LRE at 80lb inflation. So if we disregard the G614, then the Michelin XPS RIB and the Bridgestone Duravis R250 due to their all-steel ply construction will have the most reserve capacity inherent in their construction. The twin Commercial TA and Laredo will be next and the Marathon would have little or no reserve capacity available because it was used up in its higher load rating, AND because of it's much lighter construction it had much less inherent reserve capacity to start with.
So what have we learn from this?
I think that the first thing that we learned was that a LT tire can be used at or near it max rated loading without having issues, as they built with "substantial reserve capacity to accept the additional stresses of carrying heavy cargo".
The second thing we may have learned is why ST tires are failing on mid to larger 5th wheels, in that they do not have inherent reserve capacity beyond that rated max loading. Again this is because they have less reserve capacity to start with and their greater "load intensity" used up any reserve capacity that might have been available.
Now, here is an interesting bit of information. I just called Maxxis Tech Line and asked the weights for two tires.
ST235/80R16 LRD 3000 lb rating at 65 lbs of air weights 38.58
ST235/80R16 LRE 3420 lb rating at 80 lbs of air weights 43.43
What??? The Maxxis load range E tire weights almost the same as the Commercial TA?? This is a ST tire that has heavier construction than the GY Marathon at 35.4 lbs. So it has more inherent reserve capacity due to its heavier construction.
Those that claimed its virtues maybe did not know why it was a better ST tire than some of the others, but there it is! It is a heavier built tire with more reserve capacity.
So as one chooses a replacement tire or is asking for an upgrade on a new trailer please get educated on where the reserve capacity exist. Is it inherent in the tire you choose or do you have to factor it into the weight rating of the tire you choose.
Those with heavy trailers that are switching to 17.5 rims and tires rated to 4805 lbs and getting a double injection of reserve capacity, in that they are using a tire with lots of inherent reserve capacity and the tire has much more capacity than the application. It is all starting to make sense.
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