ST vs LT Tires -- I'm confused

The_Painting_Teacher wrote:
Wow! After reading so many recommendations for Maxxis, this surprised me. I went back and did a search on this site. While there are some posts critical of Maxxis tires, the vast majority of posts recommend them highly. I will continue to do research, but thanks for your input. As for the Goodyear Cargo G26, this quote is right from the Tirerack website ... "Highway Rib Summer tires are not intended to be driven in near-freezing temperatures, through snow or on ice." The G26 is labeled as a "highway ribbed summer" tire. Assuming that's accurate, that particular tire would be useless to most snowbirds. Leaning (slightly) to Maxxis, but still considering the LT's, which are limited because of the 15" rim size. Camp on!

That statement would apply to any highway ribbed tire, not just Goodyear. All it means is that a ribbed tire does not have as much traction in snow as an all-season or all-terrain tire. Thousands of commercial trailers have ribbed tires and are run year around.
Also, they use the term "driven" which to me indicates a powered vehicle, not a trailer. JMO

Francesca Knowles wrote:

elkhorn98 wrote:
I think people need to read the thread on testing requirements by the dot.

Here ya go- existing rules, as can be seen at this NTSB link:

NTSB wrote:
ST tire high speed performance test requirements.



S2Application. This standard applies to new pneumatic radial tires for use on passenger cars manufactured before 1975, new pneumatic bias ply tires, T-type spare tires, ST, FI, and...



§ 571.109Standard No. 109; New pneumatic and certain specialty tires.

CFR Title 49 571.109

S5.5High speed performance.

S5.5.1After preparing the tire in accordance with S5.4.1, mount the tire and wheel assembly in accordance with S5.4.2.1, and press it against the test wheel with a load of 88 percent of the tire's maximum load rating as marked on the tire sidewall.

S5.5.2Break in the tire by running it for 2 hours at 80 km/h (50 mph).

S5.5.3Allow to cool to 38° ±3 °C (100° ±5 °F) and readjust the inflation pressure to the applicable pressure specified in Table II.

S5.5.4Without readjusting inflation pressure, test at 121 km/h (75 mph) for 30 minutes, 129 km/h (80 mph) for 30 minutes, and 137 km/h
(85 mph) for 30 minutes.

So why don't they test ST tires at they full mythical inflated ratings rather than at 88%?????

Chris

elkhorn98 wrote:
I think people need to read the thread on testing requirements by the dot.

Here ya go- existing rules, as can be seen at this NTSB link:

NTSB wrote:
ST tire high speed performance test requirements.



S2Application. This standard applies to new pneumatic radial tires for use on passenger cars manufactured before 1975, new pneumatic bias ply tires, T-type spare tires, ST, FI, and...



§ 571.109Standard No. 109; New pneumatic and certain specialty tires.

CFR Title 49 571.109

S5.5High speed performance.

S5.5.1After preparing the tire in accordance with S5.4.1, mount the tire and wheel assembly in accordance with S5.4.2.1, and press it against the test wheel with a load of 88 percent of the tire's maximum load rating as marked on the tire sidewall.

S5.5.2Break in the tire by running it for 2 hours at 80 km/h (50 mph).

S5.5.3Allow to cool to 38° ±3 °C (100° ±5 °F) and readjust the inflation pressure to the applicable pressure specified in Table II.

S5.5.4Without readjusting inflation pressure, test at 121 km/h (75 mph) for 30 minutes, 129 km/h (80 mph) for 30 minutes, and 137 km/h
(85 mph) for 30 minutes.

I think people need to read the thread on testing requirements by the dot. St testing is less stringent. St are simply updated as our tire engineers stated due to their "occasional non passenger usage." And they are designed for local service. So if you don't tow much or far than st might work for you.

waltbennett wrote:
I had Marathons on our old 27' 10k gross TT for five years and had no problems at all. Traded it in last year for our slightly used 37' 15.5k gross Montana and it had the exact same tires on it - and they were five years old. Had Firestone LTs put on within a month. The LTs have much more sidewall flex than the ST Marathons did - and I know this because I can see them while backing into our narrow driveway from our narrow street. I believe they ride softer though, but can only say this because things don't seem to be tossed about as much as they were in the old TT.

Bottom line to me is that you've GOT to pay attention to the 'born on' dates on your tires, as well as the load & speed ratings. Anything five years old or older, or driven over it's speed rating, OR overloaded, is asking for a disaster.

Aren't those Firestones quite a bit under your trailer's GAWRs in load capacity?

FastEagle

Francesca Knowles wrote:

from actual users.

Yeah, actual users!! What a novel idea! Someone that actually owns a 5th wheel might just be step one!

Chris

Lowsuv, the other thing you fail to point out is the even with the GY ST235/80R16E having a retain price of $135, the trailer manufacturers buy ST tires and wheels pre-mounted from Tredit or Tireco for dimes on the dollar of these retail prices. My guess would be that an aluminum wheel and ST 16" tire goes for around a hundred bucks each or less for a semi trailer or train car full of them.

If one goes 10 miles once a year to the lake, they will last quite a few years. Want to see America and you better be really lucky or install quality tires.

I made a similar weight comparison back in 2009. http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/23161726/srt/pa/pging/1/page/1.cfm

Some of our tire industry insiders claim that there is not that much difference between the construction of a ST tire and a LT tire. And my response to that is why do we keep getting tire tread after tire tread about failed ST tires. Not just here but across the web. The fact that Power King and Carlisle are both trying to improve their tire design speaks volumes on the subject. Yet this latest addition of a Nylon overlay was added to the GY Marathon years ago. So I hold little hope that the new TowMax and Radial RH are the fix all.

The basic problem as you point out and I have on many occasions is that we have lightweight over rated tires that just are not up to the job for large RV trailers. Most of these tires have a tread pattern that looks like an All Season tire, which is OK on a single axle trailer, but may add to the problems on a dual or tri-axle trailer.

A good trailer tire will have a out rib with not brakes in it to grab the pavement is tight maneuvers. This new tire that Tredit is importing has a better looking tread for a ST tire than others I have seen. However we see reports of early failures on them. So it is more than jus tthe tread pattern on cheap ST tires.



Here are the GY Marathon, TowMax, and Freestar tread for comparison.







Now take a look at the Sailun LRG, which looks more like the G614 GY, XPS Rib and R250!



Chris

Dup
Chris

Lowsuv wrote:

But some folks such as Francesca , are not grasping the fact that an ST tire is less tire than the same size LT tire ..

:h
Below quoting the only thing I posted in this thread...seems to me it displays a pret-ty, pretty good grasp of the kind of "factual" info the O.P. was likely to be confronted with.

Francesca Knowles wrote:

The_Painting_Teacher wrote:
"ST vs LT Tires -- I'm confused"

You think you're confused now- just wait!

Best of luck to you....:)

Don't blame me if the O.P. actually did some research looking for info from actual users. Which research certainly didn't turn up any brand-specific recommendations from me.

Keep the hip boots on, O.P.! :B

I had Marathons on our old 27' 10k gross TT for five years and had no problems at all. Traded it in last year for our slightly used 37' 15.5k gross Montana and it had the exact same tires on it - and they were five years old. Had Firestone LTs put on within a month. The LTs have much more sidewall flex than the ST Marathons did - and I know this because I can see them while backing into our narrow driveway from our narrow street. I believe they ride softer though, but can only say this because things don't seem to be tossed about as much as they were in the old TT.

Bottom line to me is that you've GOT to pay attention to the 'born on' dates on your tires, as well as the load & speed ratings. Anything five years old or older, or driven over it's speed rating, OR overloaded, is asking for a disaster.