ST vs LT tires

[Stircrazy]

Originally Posted by wiredgeorge

Just a bit of a correction; my Carlisle Radial Trail HD ST225/75R15 LRE are rated for 81 mph by the manufacturer. I typically don't drive 81 mph but do see 65 mph regularly.

https://www.carlislebrandtires.com/o...dial-trail-hd/


This what etrailer.com says about ST VS LT tires:
Light truck tires are a type of passenger vehicle tire and as such they are not built with as thick of a sidewall as trailer tires. A thicker sidewall allows a trailer tire to handle more vertical load. ... Because trailer tires have a thicker sidewall they can build up more heat when under inflated.

yup there are going to be some better than others, but the general premis of ST tires was got one that could handle up to 65mph (that has eveolved a bit in the better ones most likly but I would imaging the china bombs are no different) I would be willing to bet (not much haha) that speed and underinflation and defects that would have been caught on a walk around, are the cause of 90% of the blowouts, road hazards being the majority of the rest. I have only lost 1 tire in 34 years of towing and it was due to a pot hole at a railroad crossing which had a lose spike and all I have ever had is china bombs. but thats not to say that I wont get something better when these ones age out.

Steve

[Ccrew]

Originally Posted by Stircrazy

there is a couple benifits of the LT tire, better speed rating (ST's are designed as a max 65mph, which is probably why there are so many failures)

Steve

Goodyear Endurance are speed rated N which is 87mph.

[tomd]

For a trailer, use the ST tires which are stiffer sidewalls. Sure the LT will work, but is not designed for the stresses applied by the the trailer (side motion for instance).


If you can upgrade load range, which depends on rim capability, I would do that. I went from load range D to E. Using Goodyear Endurance and found better than OE from Keystone. Just my opinion, but following manufactures placards attached to vehicle is safest way to go if in doubt.

[RoadToad]

Simply put, LTs are an upgrade from STs.
Has to do with load and speed ratings.
Here... READ THIS:
https://www.crossingcreeksrvresort.c...s%20D%20or%20E.

[wiredgeorge]

Originally Posted by RoadToad

Simply put, LTs are an upgrade from STs.
Has to do with load and speed ratings.
Here... READ THIS:
https://www.crossingcreeksrvresort.c...s%20D%20or%20E.

Did you actually read the article you posted? QUOTE (from the article):


LT tires typically have a significantly higher load capacity than passenger tires but a lower load capacity than ST tires. UNQUOTE


You want to put truck tires on a heavy camper, that is fine by me but I prefer to have a tire designed for a heavy camper in the first place. I don't need more than an 81 mph speed rating as I won't see that kind of speed dragging a 10K lb fifth wheel down any road.

[Ccrew]

Originally Posted by tomd

If you can upgrade load range, which depends on rim capability, I would do that. I went from load range D to E. Using Goodyear Endurance and found better than OE from Keystone. Just my opinion, but following manufactures placards attached to vehicle is safest way to go if in doubt.

I did the same in replacing rims. Stockers are only rated for 80 PSI and the endurance were rated for 85. The load rating on the stock rims was also less than the new Endurance tires. This essentially made the wheels the weak link in the system. Hence I replaced mine with an aftermarket wheel with a 110psi rating and a load higher than the tires.

[sourdough]

Originally Posted by wiredgeorge

Did you actually read the article you posted? QUOTE (from the article):


LT tires typically have a significantly higher load capacity than passenger tires but a lower load capacity than ST tires. UNQUOTE


You want to put truck tires on a heavy camper, that is fine by me but I prefer to have a tire designed for a heavy camper in the first place. I don't need more than an 81 mph speed rating as I won't see that kind of speed dragging a 10K lb fifth wheel down any road.

^^^^x2! An LT may be an option for an ST tire in some weight categories but is definitely not an upgrade. When pulling a 13 1/2' tall, 38' long box pushed by wind and physics, twisting on the tires supporting it, I want a tire made for that stress with thick sidewalls, not the ability to run 106mph which should be totally irrelevant for anyone towing a trailer like that.

[Tireman9]

I guess as the resident Tire Design Engineer I am qualified to comment.


Yes P and ST and LT tires carry different loads but also at different inflation.


You haven't told us the load you carry on the trailer so some answers may not be completely correct


Yes the trailer manufacturer selects the type & size tires based on their estimate of the load you will be carrying.


No not all ST tires have "stiffer" sidewall and I am not aware of any tire engineers working at eTrailer so I don't know who wrote their web page or where they got their information. I have found other errors on their site but so far they haven't responded to my questions.


When switching tires and changing size or type or Load Range the one thing others with some tire knowledge and I can agree on is that the new tires should have equal or greater load capability. Simply read the numbers on the tire sidewall.



Providing a picture of the certification label AKA Tire Placard sticker will answer many questions we have and allow us to make a more informed reply to your question.

[Mikelff]

Stircrazy and Wiredgeorge are correct. ST tires have the stiffer sidewalls. Used to be LT tires were used on trailers until the ST tires showed up. If the op trailer is an older trailer it probably says LT on the sticker. If you cary loads close to weight limits of the trailer, you might want to consider going to an ST tire. The tire shop guy was wrong to not give you what you wanted, but correct in stating that ST tires are made specifically for trailers. You will probably be fine either way. If you want a beefier tire, go ST. Take a picture of your sticker when you go to replace your tires and you can show them the specs on your tires. Me, I would go with ST just for piece of mind that I have tires that easily carry anything the trailer can cary with no issues. Cost difference is minimal. Biggest cost difference i have found is in brands. Speed ratings differ based on load range, as well as type of tire (LT/ST). Safe travels!

[RoadToad]

Originally Posted by wiredgeorge

Did you actually read the article you posted? QUOTE (from the article):


LT tires typically have a significantly higher load capacity than passenger tires but a lower load capacity than ST tires. UNQUOTE


You want to put truck tires on a heavy camper, that is fine by me but I prefer to have a tire designed for a heavy camper in the first place. I don't need more than an 81 mph speed rating as I won't see that kind of speed dragging a 10K lb fifth wheel down any road.

OOPS!!
Transposed my copy/paste....
My bad..

[notanlines]

“ If you want a beefier tire, go ST.” Hmmm, Trailer King ST’s, 39 pounds, Sailun 637’s 55 pounds. Where did I miss something?

[wiredgeorge]

I wanna know what kind of tires were on this little trailer! Do you think my clunker F350 can get up to 140 mph? I have had it a shade over 70 mph a few times and felt I had some more left... Now I gotta find me a LONG straight road; not easy in the Hill Country. I might head over to IH10 as I think the speed limit there is 140 mph.

https://www.youtube.com/watch?v=_E0LYU0AYG8

[LewisB]

Dang, George! Pretty hard to top that post! Good job! Those trailer tires sure look like “P’s” 😂

[notanlines]

Skip to the 4:50 spot, and don't expect much of an RV. Kind of like a Tundra speed-towing a pop-up. He 'rolled alot of coal' though for those of you who get excited over that juvenile drivel.

[77cruiser]

Nice truck, cleaned up when the turbos spooled. 1000 hp bound to puff a bit.

[JRTJH]

Originally Posted by wiredgeorge

I wanna know what kind of tires were on this little trailer! Do you think my clunker F350 can get up to 140 mph? I have had it a shade over 70 mph a few times and felt I had some more left... Now I gotta find me a LONG straight road; not easy in the Hill Country. I might head over to IH10 as I think the speed limit there is 140 mph.

I did "sort of the same thing" towing our HR Alumalite with a 93 F250 7.3L, headed west toward Albuquerque. We didn't quite make it to 140MPH, in fact, we were in second gear, about 30MPH, rolling coal with the best of them. When we finally rolled into town, at the top of the hills, the side of the HR was black, the entire trailer entry door was covered with soot and when we opened the door to go inside, there was soot on EVERYTHING !!!!! Up till then, we always travelled with the roof vents open (to create a low pressure inside the trailer and pull any dust out the roof vents)... We found, the hard way, that they also pull all that soot through any crack, crevice or opening in the trailer..... When we sold the trailer 5 years later, we'd occasionally still find a place where soot was hiding.....

So, 140 MPH on ST tires ????? Yep, that's about double what I'd feel comfortable doing, even with brand new tires of any type. I'd be concerned not only about the tires, but about the FILON and the TPO on the outside of the trailer... One little "weak spot" and I can imagine that whole "shoebox" flying apart at the seams.....

[CWtheMan]

The following is a quote a verbatim quote from the pages of a RVIA tire PDF.

" ST tires have strengthened sidewalls to prevent the tire from rolling under the rim in turns when cornering. P & LT tires, on the other hand, have flexible sidewalls to allow for greater traction and ride comfort. Sidewall flexing on trailers, especially those with high center of gravity or that carry heavy loads (such as travel trailers of fifth wheel trailers), is a primary cause of trailer sway. Therefore, the stiffer sidewalls and higher operating pressures common with ST tires help reduce trailer sway."

[wiredgeorge]

I believe the video of the stupid speed run said that the trailer tires were changed out for V rated tires. Given the light weight of the trailer and limited duration of use, the tires evidently didn't blow up. Although the guys doing this video were nuts, I guess they didn't want to find out how ST tires performed at 140 mph.

[flybouy]

Originally Posted by wiredgeorge

I believe the video of the stupid speed run said that the trailer tires were changed out for V rated tires. Given the light weight of the trailer and limited duration of use, the tires evidently didn't blow up. Although the guys doing this video were nuts, I guess they didn't want to find out how ST tires performed at 140 mph.

Like the Bentley Veyron with a top speed >250 mph. IIRC the tires were good for about 100 miles at that speed. The shame of it is stupid acts like that will prompt some idiot to say "That's nothin', hold my beer and and watch this!"

[Tireman9]

The SAE speed test which is the one used by tire companies is a 30 minute step speed test. Only need to run 30 min to be rated for 87 or whatever your ST tires are rated for.


The load formula for ST type tires is still based on 65 mph operating speed.