LT Tire vs ST Tire
I assumed I wanted ST Tires for my camper and some people are telling me to go with LT Tires. Now I'm confused, and guess I shouldn't assume.
Forum Discussion
62 Replies
kedanie wrote:
Seems there will never be an end to tire arguments!
Give it a rest folks!!!
Keith
Good idea.- Seems there will never be an end to tire arguments!
Give it a rest folks!!!
Keith Huntindog wrote:
Yes there has. The govt. does the tests.....
Sorry, the government does not conduct the tests. The tire manufacturer does the tests.
The government might test a tire or 2 to verify compliance, but they do NOT conduct the certification test for each and every tire on the market. They can't. Way, way too many.
- AND MOST IMPOTANT -
When the government does test a tire, it will do so according to the test procedure applicable to each type of tire. They will NOT test an ST tire to LT tire conditions and vice versa.Huntindog wrote:
.....The so called weight advantage of the ST is very slight.. The speed superiority of the LT is signifignant....
Sorry, but the math says they are in line with each other.
Note: Please be aware you can't compare a 10% load carrying capacity with a 10% speed difference. It doesn't work that way. It's an exponential curve.Huntindog wrote:
LTs were around before STs came into existence.. In fact they were the original trailer tire.....
Sorry, but ST tires came into existence the same year LT tires did. Go find the Tire and Rim Association Yearbooks, Oh, about 1968, and look it up yourself. Prior to that there weren't LT tires (or ST tires). They used a different system. and they didn't use letters.
In fact, prior to the introduction of LT metric and ST tires (and P metric, for that matter) the difference between tires used on trailers and tires used on pickup trucks was the notes on the tables involved. Tires on trailers were allowed to have more load carrying capacity BECAUSE they were operated at slower speeds.
Oh, and LT tires back in those days didn't perform very well. Certainly not up to the standards of today.Huntindog wrote:
......The ONLY thing stricter for the ST tire tests is the 3% tougher load requirement........
Ah, that is part of the problem.
An LT235/85R16 LR E has a load carrying capacity of 3042# at 80 psi.
An ST235/85R16 LR E has a load carrying capacity of 3640# at 80 psi.
So it's more like 20%.Huntindog wrote:
...... But the rest of the LT tires testing is so severe, that I would wager a tidy sum that the LT tire is easily capable of meeting that test requirement as well........
Ordinarily, I would point to your other factual errors and take you up on your bet, but I happen to agree with you - but for a different reason.Huntindog wrote:
......I would wager a whole LOT of money that the STs cannot pass the LTs tests.......
And not only is it here we disagree, but you have proved my point.
You do not KNOW of anyone who has done the testing.- As I've stated before. The advocates for ST tires are usually the same people that have never pulled a trailer on trouble free LT tires. Drink the ST Kool-Aide if you like. I'll wave as I pass you on the side of the road..
B.O. CapriRacer wrote:
Lowsuv wrote:
........Every LT tire meets the standard for ST ratings .
ST tires do not meet the LT standards ......
Sorry, but while the standards are different between ST tires and LT tires, there hasn't been anyone who has done the testing to verify that.
Yes there has. The govt. does the tests.
They are the same in many respects for both tires.
In fact there is a slight, 3% stricter weight carrying standard for STs.... But the LTs standard is 16% stricter for speed, AND the LT has to run severely underinflated for 2 hours at 75 MPH without failure.. The ST does not have to perform this test.. So in reality, The LT pretty much has to do everything that a ST does,,,, and much more.
ST tires are designated to have a larger load carrying capacity, but have a speed restriction of 65 mph. LT tires have a lower load carrying capacity, but have a higher speed capability.
The so called weight advantage of the ST is very slight.. The speed superiority of the LT is signifignant.
You can argue that ST tires aren't built as well as LT tires - either because of the quality of the design or the quality of the manufacturing material and/or processes - but ST tires are designated for a certain task and LT tires are designated for a different task.
LTs were around before STs came into existence.. In fact they were the original trailer tire.
So the LT is a multi task tire.. In fact it is LEGAL to use a LT on a trailer, but ILLEGAL to use a ST on a automobile!!
Nevertheless, there isn't any evidence that either will pass the other's testing requirements.
The ONLY thing stricter for the ST tire tests is the 3% tougher load requirement... But the rest of the LT tires testing is so severe, that I would wager a tidy sum that the LT tire is easily capable of meeting that test requirement as well.
I would wager a whole LOT of money that the STs cannot pass the LTs tests.- Just make a very tight turn with your truck and trailer. Stop halfway and inspect your trailers tires and suspension. You will find that one tire is bent in about 1.5 inches and the other is bent out 1.5 inches. This is the normal operation of a dual axel suspension system. The trailer suspension uses every mm of tolerance of the ST tire sidewall flex and axel bend to make it around a corner.
Installing a LT tire with higher traction characteristics in trailer suspension system will transfer higher levels of force to all the components in the system.
There have been many reports of bent axels and spring mount fracture at weld points along with lots of bent component problems. This system doesn’t need the higher forces associated with a LT tire.
When it comes time to replacing the ST tires, I will be matching the manufactures specifications. There are many ST tires now manufactured to a higher quality standard. I am currently running a Chinese Ameritrac “Power Towing” ST tire that is built with the third nylon cap design. I have made two cross country trips from Michigan to California without any problems. I see Maxxis tires in my future.
MM49 - IMHOP go with LT tires if you have the clearance, if not stay with an E rated ST tire
Lowsuv wrote:
Designation is the KEY word regarding ST versus LT .
1) The standards are higher / tougher for the LT tire .
The evidence that shows up is when you compare the load ratings for equivalent size & load range tires , ST vs LT .
2) The ST tire is often sidewall rated for a higher weight rating than the LT tire ,
even though both tires are the same size and PSI Load Range .
#1 YOU are basing your WHOLE premise on LTs being superior to STs SOLELY ON SPEED RATINGS.
That is a FALSE sense of security, just because a tire is rated at 75 or even 100 MPH does not mean it is totally superior and can replace all other tires in all cases.
Are YOU an TIRE engineer that you can make this call?
I doubt it.
#2 YOU ARE actually making the aurgument FOR STs being that STs ARE SUPERIOR in the SIDEWALLs over LTs.
In the case of multi axle trailers THIS IS where STs are designed for.
Multi axle trailers put a SEVERE SIDE LOAD on the tires when cornering (IE TURNING) so unless you never, ever TURN (IE DRIVE IN A STRAIGHT LINE) you ARE heavily loading LT tires on the sidewalls BEYOND what they are designed for.
LT tires are also designed to GRIP the road (IE TRACTION), with trailers you do not need this grip, in fact this grip actually makes the tires STICK to the road while turning which puts even more excessive side load on the tires, running gear, frame.
ST tires are designed with LESS grip which allows them to break traction when a side load is presented. This allows the tires to "hop" a bit to help relieve excess side loads.
LTs under excessive side loads may grip hard enough to roll the bead loose if you don't end up bending or breaking the running gear in the process.
If you have ever watched a multi axle trailer from the back when they are making a tight turn you WILL see the axles SHIFT side to side by several inches.
The ONLY reason folks tend to get away with LTs is by moving drastically up the load rate. This often means higher tire pressures which in turn means buying higher pressure rated rims and often larger rims.
The danger in this is by using higher pressures you are now subjecting your trailer to a firmer ride which if not designed for that can cause other damage to the running gear and even the contents of your trailer.
Think of running higher pressures as the same as not having any spring suspension, the entire frame and anything else on that frame gets shocked harder for a given bump.
Everyone likes to blame STs for their blowouts the problem is no one has brought forth any actual PROOF they THEY HAVE SEEN with their own two eyes at the EXACT MOMENT when the tire failed. Instead they bring forth the EVIDENCE of a tire failure but not any EVIDENCE AS IT HAPPENED.
Basically put, unless you have cameras on each tire, cameras watching the road path in front of the tire (no objects to puncture like bolts, nails screws, wood, metal or even potholes), cameras INSIDE the tire and you never ever make a turn, hop a curb or any other unusual things you have NOTHING OTHER THAN AN OPINION.
Tires blow, even LTs, I lost one on my truck years ago when I DROVE OVER A BOLT LAYING ON THE ROAD. I never saw the bolt, the front tire drove over it fine but the back tire BLEW OUT when it contacted the bolt. While I didn't find the bolt, the tire shop pointed out the SIZE of the opening on the INSIDE of the tire was about the size of a bolt.
Go ahead and use what you "feel" is good for you if it makes you happy, but perhaps you should rethink the position that LTs replace in ALL situations..- Regarding Costco :
Costco installed LT 265R16 load range E michelin tires on my Duramax pickup that came with LT 245R16 LRE tires from the factory .
I know Costco online will not allow you to do a search for a different size than OEM .
At my local Costco I have never seen a travel trailer getting new tires there .
But last weekend I did see Costco installing new tires on a new Bentley Coupe .
This is in a town of 85,000 people about 140 miles from the next largest population center .
Costco has a limited range of inventory sizes and any specialized tires have to be ordered in advance .
I buy everything I can from Costco . High quality at a good price .
But the last two sets of tires I bought from Tire Rack . - Designation is the KEY word regarding ST versus LT .
The standards are higher / tougher for the LT tire .
The evidence that shows up is when you compare the load ratings for equivalent size & load range tires , ST vs LT .
The ST tire is often sidewall rated for a higher weight rating than the LT tire ,
even though both tires are the same size and PSI Load Range .
