LT tires on TT

JIMNLIN wrote:
What you have always failed to recognize is the fact that tire manufactures are not supposed to make the tire recommendations that you always seem to recommend.

OK, they make recommendations to the vehicle manufacturers.

FE

I look at it this way , I havent seen a " LT" tire stamped with anything saying truck use only , or do not use on trailers . BUT I have seen on " ST " tires for "trailer use only" This makes me wonder are they not made good enough for a truck ? If I were making tires I could sell a lot more truck tires VS trailer tires .

FastEagle wrote:
What you have always failed to recognize is the fact that tire manufactures are not supposed to make the tire recommendations that you always seem to recommend.

Your incorrect on who may make that recommendation.

Maybe you and others that are so sure about what regulations and standards really mean should get some interpretations from the source. When someone like me does it you call it “loaded”.

My and others source of facts and info came from the tire makers many years before you became a RV.net member or ever pulled a trailer.
What you fail to recognize is there is nothing regulatory in nature on proper tire selection for a trailer as in this case.

Loaded question ??

And as usual non of your clicky's leads us to your so called regulations your always throwing around trying to scare folks into your ideas/opinions. The clicky's are simply a guideline or recommendation to new folks who don't know how to choose a proper tire for their vehicle.

OP says his buddy and quote;
"TT GVWR is 9000 and current tires are ST225 75 R15 LR-D and he wants to go to LT225 75 R 16 LR-E. New rims are rated to 90psi."

The LT he is choosing is a proper fitment.

Francesca Knowles wrote:

JJBIRISH wrote:

Actually in that situation I might use the P rated over a LT tire…

-
No kidding- especially given that according to some studies, P-tires are three times safer than LT's- a little known factoid in some crowds.

Here quoting from this NTSB page:

NTSB wrote:
The rate of blowout-caused crashes for light trucks (0.99 percent) is more than three times the rate of those crashes for passenger cars (0.31 percent).

Blowouts cause a much higher proportion of rollover crashes (4.81) than non-rollover crashes (0.28), and more than three times the rate in light trucks (6.88 percent) than in passenger cars (1.87 percent).

Too bad P-tires are so flabby...but there might be some out there that would do the trick.

Well, and part of the problem is that many of the choices in P metrics ( that would have adequate load capacity ) require rim widths that are wider than we typically have on trailers. So yes, "if" we can find a rim wide enough, with zero offset, then we could have some more choices in the P metric lineup.

I was actually being just a bit cheeky in my post above using that K-ho P-metric tire as an example, because truthfully, many trailers that are as light as my funfinder only have a single axle. So "if" mine did have a single axle, then using P metrics on it would be out of the question, as they would be overloaded.

I love my tandem axles...:C

JJBIRISH wrote:

Actually in that situation I might use the P rated over a LT tire…

-
No kidding- especially given that according to some studies, P-tires are three times safer than LT's- a little known factoid in some crowds.

Here quoting from this NTSB page:

NTSB wrote:
The rate of blowout-caused crashes for light trucks (0.99 percent) is more than three times the rate of those crashes for passenger cars (0.31 percent).

Blowouts cause a much higher proportion of rollover crashes (4.81) than non-rollover crashes (0.28), and more than three times the rate in light trucks (6.88 percent) than in passenger cars (1.87 percent).

Too bad P-tires are so flabby...but there might be some out there that would do the trick.

There is a well known and respected Airstream dealer that actually recommends a BFG Radial T/A passenger tire for some of his customers that are looking for replacements on some of the older ( lighter ) A/S trailers. He claims to have fit many of them to various customer's trailers, and reports very good success.
Airstream owners are a group that "really" fears, and hates tire failures. Tread separation tends to just beat the holy snot out of the aluminum body panels.

gmw photos wrote:
To further muddy the waters, use my funfinder tandem axle trailer as an example. I could in theory use a Kumho passenger tire, Solus KR21 215/70-14. Load cap 1554@44 psi. Minus 9% for fitting it to a trailer, equals 1414 pounds at 44 psi. This tire is allowed to fit to a 5.5 to 7 inch rim. My rims are 5.5".

Well look at that.... 1414 times two is 2828 pounds. The trailer has axles that are rated for 2800 pounds, so these lowly passenger car tires would exceed the load cap of the axles. :)

And, in my case, my trailer weighs 3974 pounds according to the local CAT scale, of which, about 3400 is on the axles. So I would have 5656 pounds of capacity carrying 3400 pounds, which is a 40% reserve.

Heh, heh..... I'd PERSONALLY run them before I'd run any ST tire ... :B

Actually in that situation I might use the P rated over a LT tire… but I am not sure I would choose the same P rated tire…
going strictly by failures I believe the P rated tire beats them all…



yes they are built to be cheap and the only pressure on builders is from the trailer industry to keep the cost down… but other industries and buyers do the same, just not to the degree of the trailer industry…

I think in Francesca's post above, she hit the nail squarely on the head as to why the RV ( and other trailer manufacturers ) companies use ST tires: LOWER COST per tire.

If you are the top dog at a trailer company, you might tell your employees, "find the parts to build these trailers, that meet all the standards for the use of this trailer. And oh by the way, find the parts that meet those standards, at the lowest possible cost to us".

Congratulations....welcome to world of ST tires. Cheap, and meet the minimum standards. We therefore can say they are "adequate", so to spend more money on more expensive components simply robs us of bottom line profit.

I was only quoting what the tire builders say in an official capacity on the web site and catalogs and what they state publicly…
I will defer to the acclaimed tire builder Michelin and what they have said… apparently that was missed when you read it… :)

Most trailer tires are ST type tires that carry more weight and are designed for trailers.

If the trailer maker specifies an ST type tire then using an LT type tire would be a misapplication and would void the warranty.


If the trailer maker specifies an LT type tire would be approved then and only then would the LT tire be used.



This has nothing to do with what I think about LT tires or ST tires (you know what I think about them) I am well versed on the testing and certification procedures, it would be easier to ignore the rest of the facts and just go with that but that isn’t the whole story… it is about the official position of the tire builders and their associations not mine…

To further muddy the waters, use my funfinder tandem axle trailer as an example. I could in theory use a Kumho passenger tire, Solus KR21 215/70-14. Load cap 1554@44 psi. Minus 9% for fitting it to a trailer, equals 1414 pounds at 44 psi. This tire is allowed to fit to a 5.5 to 7 inch rim. My rims are 5.5".

Well look at that.... 1414 times two is 2828 pounds. The trailer has axles that are rated for 2800 pounds, so these lowly passenger car tires would exceed the load cap of the axles. :)

And, in my case, my trailer weighs 3974 pounds according to the local CAT scale, of which, about 3400 is on the axles. So I would have 5656 pounds of capacity carrying 3400 pounds, which is a 40% reserve.

Heh, heh..... I'd PERSONALLY run them before I'd run any ST tire ... :B