RV Tires

[Francesca Knowles]

Originally Posted by Brian B-P

...built to LT standards, and clearly designated as such on the sidewall and in all Goodyear spec sheets for it, including the one linked above. Francesca, why do you refuse to read the authoritative information provided?

Because I'm a know-it-all blabbermouth, that's why! Duh....

Funny they stamp that "LT" on the tire but use "ST" in the name...not to mention call it a trailer tire at their own website. I wonder if it has anything to do with the 65mph speed rating limit for ST's. This one definitely has a higher limit...

O.K.!

I'll give you that one- there's an LT-labeled tire that's actually marketed by the manufacturer as suitable for trailers! And it's got the stiff sidewalls and shallow/simple tread pattern like ST's do...that's good for stability and rolling resistance...
It's a load range "G", too. Wow- 3700 pounds of capacity each!!!

That's a lot of tire...

My verdict:

If one needs 16 inch tires with that much capacity and has $300.00 per tire to spend: Go for this one!

Francesca

P.S.

Was that any better?

F.

[Brian B-P]

Originally Posted by Francesca Knowles

Funny they stamp that "LT" on the tire but use "ST" in the name...

It's just a couple of letters in the name. "ST" has been used as a trim level designation for some car models, perhaps to indicate "Sport Touring" - it doesn't necessarily mean "Special Trailer".

Originally Posted by Francesca Knowles

I'll give you that one- there's an LT-labeled tire that's actually marketed by the manufacturer as suitable for trailers!

There are actually many tires intended and used (by vehicle manufacturers as original equipment) for applications (such as light trucks, vans, and even trailers) which do not correspond to the tire construction standard name (P, LT, ST). It is particularly common for "half-ton" pickups and SUVs to use P tires. In any case, the tire characteristics and ratings (for the specific size used) must be appropriate for the use... which is the only point anyone needs to get out of this discussion.

[Francesca Knowles]

Originally Posted by Brian B-P

It's just a couple of letters in the name. "ST" has been used as a trim level designation for some car models, perhaps to indicate "Sport Touring" - it doesn't necessarily mean "Special Trailer".

.

It's a lit-tle more than that when it comes to tires, Brian-me-lad...

For one thing, those labeled "ST" must also be labeled with the maximum speed limit of 65 mph...

There's more to it, but since this is beginning to sound more like a church service than a discussion I'll leave all closely held belief/doctrinal issues to folks' Individual Consciences!

Francesca

[Glenn Baglo]

How long does it take to Tire of a topic?

[rabbit]

I've been gunshoeing around after Floyd and his references. On the Goodyear RV tire rec site I find this:

"Be safe - if a tire has been run 20% underinflated, it must be dismounted and inspected by a trained professional. It should not be aired up without a fullinspection or without using a safety cage. Use a calibrated gauge. If your tire is rated for higher inflation pressures, a special gauge will be required designed for larger tires".

There is no reference this site to ST tires but the language is revealing about Floyd's contention that a "minimum" pressure is any particular pressure in the ST chart indexed to a particular load that it is expected to carry. I spitballed that I could run 43lb. in an ST 205/75R14 to adequately support a load of 1620lb. This is exactly what the chart indicates. My guess is that Floyd thinks that because 43lb is roughly 20% under the 50lb max inflation pressure on the 205, this is the threshold at which the tire must be dismounted and inspected BEFORE being put in service at this pressure.

Note that 1) the bullet point from Goodyear above indicates that the tire should be D&I if it has already BEEN IN SERVICE at 20% underinflation, and 2) it is NOT STATED that 20% underinflated means 20% under maximum inflation pressure.

I'm wondering if 20% underinflation really means 20% under for each tabulated pressure/load combination in the chart? Those who advocate max psi for every possible load up to the stated load capacity of the tire appear to believe that sidewall flex is the paramount issue which will not allow us to even contemplate multiple levels of inflation. If anyone IS still interested, what's your thought?

jack

[Francesca Knowles]

Originally Posted by rabbit

I'm wondering if 20% underinflation really means 20% under for each tabulated pressure/load combination in the chart? Those who advocate max psi for every possible load up to the stated load capacity of the tire appear to believe that sidewall flex is the paramount issue which will not allow us to even contemplate multiple levels of inflation. If anyone IS still interested, what's your thought?

jack

As long as it's strictly technical and you don't go all "religious" on me... I'm still interested!

Tire load pressure recommendations are given as those load-related pressures under which the tire referenced will continue to perform as intended. In the case of ST's, that means that sidewall stiffness/tracking will be consistent with design performance/parameters.

Francesca

[rabbit]

If I am even minimally-capable of understanding what you say, Francesca, I agree with your interpretation of the possible practical use of correlated levels of load and inflation pressure as presented by tire makers. I am suffering a lot of self-doubt lately as I am apparently not capable of understanding some things which I have heard repeated 10 times in this thread. I think that makes me a devout Missourian but others may have a different word for me.

jack

[floyd]

Originally Posted by rabbit

I've been gunshoeing around after Floyd and his references. On the Goodyear RV tire rec site I find this:

"Be safe - if a tire has been run 20% underinflated, it must be dismounted and inspected by a trained professional. It should not be aired up without a fullinspection or without using a safety cage. Use a calibrated gauge. If your tire is rated for higher inflation pressures, a special gauge will be required designed for larger tires".

There is no reference this site to ST tires but the language is revealing about Floyd's contention that a "minimum" pressure is any particular pressure in the ST chart indexed to a particular load that it is expected to carry. I spitballed that I could run 43lb. in an ST 205/75R14 to adequately support a load of 1620lb. This is exactly what the chart indicates. My guess is that Floyd thinks that because 43lb is roughly 20% under the 50lb max inflation pressure on the 205, this is the threshold at which the tire must be dismounted and inspected BEFORE being put in service at this pressure.

Note that 1) the bullet point from Goodyear above indicates that the tire should be D&I if it has already BEEN IN SERVICE at 20% underinflation, and 2) it is NOT STATED that 20% underinflated means 20% under maximum inflation pressure.

I'm wondering if 20% underinflation really means 20% under for each tabulated pressure/load combination in the chart? Those who advocate max psi for every possible load up to the stated load capacity of the tire appear to believe that sidewall flex is the paramount issue which will not allow us to even contemplate multiple levels of inflation. If anyone IS still interested, what's your thought?

jack

Actually.... I said what I meant to say, and I'll allow you to speak for yourself. The information I was referring to was on a PDF format on the tire sites. I can't figure out how to extract quotes from a PDF file.

[rabbit]

. . .and an elephant's faithful 100%. I'll backtrail thru your posts and check the pdf. Thanks.

jack

[Jared J]

I found this. Not exactly a guarantee, but they should know.

Tire Tech Information - Trailer Tires vs. Passenger Vehicle Tires

"Also consider that Special Trailer (ST), as well as Light Truck (LT) tires are fully rated for trailer applications. This means ST- and LT-sized tires can carry the full weight rating branded on the sidewalls when used on a trailer.However when P-metric or Euro-metric tires are used on a trailer, the load capacity branded on the sidewalls must be reduced by 9%. This means P-metric or Euro-metric tires with a maximum branded load rating of 1,874 lbs. for use on a car is only rated to carry 1,705 lbs. when used on a trailer."

Originally Posted by rabbit

I've been gunshoeing around after Floyd and his references. On the Goodyear RV tire rec site I find this:

"Be safe - if a tire has been run 20% underinflated, it must be dismounted and inspected by a trained professional. It should not be aired up without a fullinspection or without using a safety cage. Use a calibrated gauge. If your tire is rated for higher inflation pressures, a special gauge will be required designed for larger tires".

There is no reference this site to ST tires but the language is revealing about Floyd's contention that a "minimum" pressure is any particular pressure in the ST chart indexed to a particular load that it is expected to carry. I spitballed that I could run 43lb. in an ST 205/75R14 to adequately support a load of 1620lb. This is exactly what the chart indicates. My guess is that Floyd thinks that because 43lb is roughly 20% under the 50lb max inflation pressure on the 205, this is the threshold at which the tire must be dismounted and inspected BEFORE being put in service at this pressure.

Note that 1) the bullet point from Goodyear above indicates that the tire should be D&I if it has already BEEN IN SERVICE at 20% underinflation, and 2) it is NOT STATED that 20% underinflated means 20% under maximum inflation pressure.

I'm wondering if 20% underinflation really means 20% under for each tabulated pressure/load combination in the chart? Those who advocate max psi for every possible load up to the stated load capacity of the tire appear to believe that sidewall flex is the paramount issue which will not allow us to even contemplate multiple levels of inflation. If anyone IS still interested, what's your thought?

jack

I think it means for the weight rating, but it's hard to say. I.E., in your example, 20% under the 43 lbs.

I work on jets, we have something like it, but they only have one rated tire pressure to use. A 200 p.s.i. tire can go down to something like 110 p.s.i. and be inflated, as long as it hasn't rolled. If it's rolled, it can go down to something like 160 lbs. Anything under those, it's scrap. There's another set of pressures that if it's under, makes the tire next to it, scrap.

My personal preference is just running max pressure. It'll take the speed and weight better. If by chance, that means my camper will be bouncing all over the place, I'll consider lowering it. If it rides well at max pressure with the new tires, then they shall remain at max pressure.

Already running ST tires out of spec (speed wise), its been obvious max inflation plays an important part, even when not fully loaded. They will shred themselves below max spec. They don't do great even at max pressure, but it's much better.

[rabbit]

In post 65 above, 1630lbs. should read 1560lbs as the individual tire load on my trailer as weighed recently.

The example from aircraft tires does a pretty good job of clarifying the piece of the elephant that I (and perhaps others) are struggling with. I may have to accept Floyd's and your view, Jerod, that I should just dynamite to max psi and have done; in fact that is what I've been doing. Maybe it's a quibble but I had a heck of a time with the idea of the "minimum" tire pressure as presented by Brian and Floyd. However, I am willing to give back the goats and call it a nite and an end to my participation in this thread (except for the bounce test at 43 and 50psi). Probably have bad dreams after they've "rolled" at the lower pressure, even for five miles.

jack

[floyd]

Originally Posted by rabbit

. . .and an elephant's faithful 100%. I'll backtrail thru your posts and check the pdf. Thanks.

jack

I doubt you'll hear a Who, but then nobody(but us) believes in them anyway.

While I am not claiming Discount Tire as the definitive authority,I did find the following page from their web site to be interesting reading.
Note the admonition in the left margin, it is the same as the one given by Carlisle Tire Company.
Trailer Tire Facts - Discount Tire

[steve dunham]

When I bought my new tires for my Scamp the tire dealer had filled the tires to 65 lbs PSI and told me to run them at the maximum air pressure listed on the sidewall of the tire (65 lbs PSI) . I also called the tire manufacturer and was told to run the tires at the maximum air pressure of 65 lbs. PSI . So I went to the Discount Tire website Floyd linked in his post and they say run the tires at the maximum pressure as listed on the tire. I do not understand all the discussion over tire pressure it seems a rather nuanced point

[Carol H]

Originally Posted by Francesca Knowles

There's more to it, but since this is beginning to sound more like a church service than a discussion <cut> Francesca

Originally Posted by steve dunham

I also called the tire manufacturer and was told to run the tires at the maximum air pressure of 65 lbs. PSI . So I went to the Discount Tire website Floyd linked in his post and they say run the tires at the maximum pressure as listed on the tire. I do not understand all the discussion over tire pressure it seems a rather nuanced point

Both points worthy of an amen from me

[Jon Vermilye]

Originally Posted by Francesca Knowles

Thanks for the catch on my "Michelin" blooper, Brian- fixed on edit!

Per exceeding stamped maximum sidewall pressure:

It should be noted that the bulletin does specifically caution against exceeding the PSI limit of the wheel that the tire is mounted on.

I wonder how many folks even know that there is such a number?

Since it's usually stamped on the tire-bearing surface, demounting the tire is required to see it...

Francesca

This is particularly important if you have 15" wheels & are considering Maxxis's D rated 205/75/15 as a replacement for C rated tires. A number of forums have discussed replacing Marathons with Maxxis 8008 tires.

I checked with Escape & the rims supplied with my Escape 17 are rated for 50 psi. Maximum pressure for the Maxxis D rated tire is 65 psi, well above the rim rating.

[Brian B-P]

Originally Posted by Francesca Knowles

It's a lit-tle more than that when it comes to tires, Brian-me-lad...

"S" and "T" are indeed just a couple of letters in the name of the tire. It could just as well have been called "X999 ABC", or "Francesca".

ST as the first two characters of the tire's size/type designation have the specific meaning of compliance with the Tire and Rim Association's ST standards... and the designation of that infamous tire with "S" and "T" in its name (Goodyear's G614 RST) does not start with "ST" and it does not follow TRA ST standards (it starts with LT because it does follow TRA LT standards).

From the same Goodyear commercial collection, the G171 LT and G149 RSA LT do not follow TRA LT standards... but why would they, since "L" and "T" are just letters in the names.

Perhaps the lesson here is to read the specs, and not make assumptions based on model names or other marketing fluff.

Originally Posted by Francesca Knowles

For one thing, those labeled "ST" must also be labeled with the maximum speed limit of 65 mph...

Almost correct, and probably one reason that there are non-ST options suitable for trailers.

[Francesca Knowles]

Originally Posted by Brian B-P

Perhaps the lesson here is to read the specs, and not make assumptions based on model names or other marketing fluff.

Much better to make those assumptions based on the apocryphal blather one reads in trailer forums, eh?

Originally Posted by Brian B-P

there are non-ST options suitable for trailers.

WHEW!
It took awhile, but you've finally come a-l-l-l-l the way back around to my original question:

Which tires other than ST's does a manufacturer specifically recommend for trailer use?

Other than the tire that Goodyear itself defines as a Commercial Trailer Tire but sticks the according-to-you meaningless letters "LT" on the sidewall, I mean. On that subject, perhaps you won't mind confining the offerings to those that do NOT require rims capable of enduring 110 pounds of pressure as does your first suggestion....

Francesca

P.S.:

I wish I knew how to post the "Word Cloud" the following excerpt made- it's very instructive! That cunning use of bold combined with withering sarcasm...

Originally Posted by Brian B-P

"S" and "T" are indeed just a couple of letters in the name of the tire. It could just as well have been called "X999 ABC", or "Francesca".

[Jared J]

I emailed maxxis to get their take on it. I also don't get 65 p.s.i. trailer wheels, that seems ridiculous. I never even considered that a possibility. I emailed ultra to see what mine are rated for. I'm going to be terribly peeved if they made trailer wheels that can't take the pressure of a trailer tire.

[Francesca Knowles]

I assume you already tried looking at Ultra's site online...I don't see any information there other than some real purty pictures (assuming I'm looking in the right place)...weird!

You'd think that PSI limits would be an important bit of info for shoppers!

I'll be interested to hear what you find out.

Francesca

[Brian B-P]

Originally Posted by Francesca Knowles

Much better to make those assumptions based on the apocryphal blather one reads in trailer forums, eh?

No, better to read the specifications.

Originally Posted by Francesca Knowles

Other than the tire that Goodyear itself defines as a Commercial Trailer Tire but sticks the according-to-you meaningless letters "LT" on the sidewall, I mean.

Francesca, do read all of the words of any post? The LT that starts the designation is the meaningful part - not some random letters picked out of the name - because that leads to the correct specs... as I have posted several times.

Originally Posted by Francesca Knowles

On that subject, perhaps you won't mind confining the offerings to those that do NOT require rims capable of enduring 110 pounds of pressure as does your first suggestion....

Read my posts: I didn't suggest any tire for anyone, just listed an example of a tire which is suitable for trailer use, is not ST type, and is specifically LT type.