Question about tires

[Heybro]

I have been learning a lot about tongue weight and payload capacity lately, but I have not even looked into tire capacity and weight rating at all. I am going to need some help with this. So my truck has Goodyear 275/55R20 113T tires. It says the treadwear is 500, Traction B, Temperature B. It also says the max load is 2535 lbs, and max psi is 51.

My GAWR on my truck with those tires is 4000 lbs on the front, and 4150 lbs on the rear.


Ok, with that information, how do I figure out if I am good to tow a 7,000 lbs GVWR trailer, with 680 lbs of dry tongue weight without having a tire blowout? I heard something that you need D or E rated tires if you are going to tow. But it looks like my tires can handle 2535 lbs each, so shouldnt i be fine?

[Grit_dog]

^Sort of. If that’s the right pressure for the load.
OTOH, I have tires on our current truck, that I couldn’t reasonably put enough weight on the truck to need to run them anywhere near max pressure.

[Timeking]

I have the Nokian HT One tires (51 psi max) on my 2016 RAM 1500.

TT hooked up with WD.

With 50 psi in rear and 40 front, rims are both at 24 1/4 inch high (top of rim to ground).

With 44 in rear and 40 front, rear is at 24 and front at 24 1/2.

So ... it seems advice to max rears is valid.

[BarneyS]

BenK wrote:
Snip...

Aspirin anyone ?

Yes - PLEASE!:E
Barney

[BenK]

Boils down to understanding...or not...of what a rating is...and in this topic...reference to tires.

Let out all the PSI from a tire with the vehicle weight on it

Rim will be down to pavement with the tire carcass between them

Air up and at some PSI point, the rim will lift the vehicle weight off the pavement

Continue airing, increasing the PSI and the rim will lift even higher, as now the tire ‘can’ carry more weight

Then up to the PSI as mentioned by one of our resident tire engineers (CapriRacer) and is the ‘rating’ for ‘that tire

Increasing the PSI will have the tire be able to carry more weight, but it will not be ‘rated’ for it (same metric for discussions of TV ratings and what they can carry/tow)

That increased PSI over max rated weight carry is more to keep the tires shape during its multitude of duty’s...carry weight, braking, accelerating, cornering, etc, etc, etc

Sure it ‘can’ carry more, but not within the specifications published (labels, brochures, specification sheets, etc) and be able to meet the criteria employed during design and certification testing.

That is where comments of : “into the safety margins” means. It will do it...but how long, how safely, etc. Big one is duty cycle and that is another area not understood by too many.

Gives me a headache trying to explain designed to specifications and ratings. What is baked into that design is lost to those who do not understand the process

This is a ditto for everything engineered or designed to a specification

One example that has worked on one of my old forums...with shooters/reloaded. They understood receiver/chamber pressure ratings. Sure you can increase the powder charge to increase the pressure and have the bullet fly faster/flatter/farther/etc...but they understood that it might work for a while or instantly fail...but the understood that it WOULD fail sooner or later...the working load and breaking load of a rope also worked for non shooters...

Aspirin anyone ?

[MFL]

CapriRacer... no need to apologize, your opinion is worth just as much as mine.

I agree on the confusing. Hard for everyone, to keep up on the new ratings of various TV tires. The OPs tires are called light truck for 1/2 T trucks/heavy SUVs, but not designated LT in that size. I was wrong to suggest to Jim, that they are LTs, and he is knowledgeable enough to know that. He has real world experience, and stays current, concerning tires, making him, IMO, a top source of tire info, on this forum. Now add in towing large trailers, which you can only learn from experience, what works the best. Using your example, the 44 psi will LIKELY work best, even if max load may begin at a slightly less psi. Like I suggested much earlier, if you could borrow a TT with 1K+ TW, hooked up to a modern 1/2 ton, you could try it, come back, tell us what you learned.

Didn't mean to seem condescending earlier in the thread, but did not want the OP to take advice of towing that heavy, with low door sticker inflation. He was wanting to know if his tires were adequate, and the answer is yes, with proper inflation. More psi will make his towing experience better, especially in the rear. After 6 pages of opinions, I hope he sees this is by far the most popular opinion, of experienced towers, that posted in this thread.

Jerry

[Grit_dog]

Or to sum up the last 6 pages for the guy who just wants safe tires for his truck pulling the camper, the tries that are on it are perfectly fine at the loads they'll see and will handle quite well when aired up appropriately.
And LR D or # tires would be even stiffer, aired up appropriately or a bit more and they'll last longer than the comparable P/XL tire.

[CapriRacer]

MFL wrote:
Jim, not to discredit the tire boys, but the manufacturer of the OP's tires says they are LT tires, which I suspect is true with a max psi of 51 and 2,535 LR. .....

Sorry, but here's another correction:

1) P type Standard Load tires will have a max pressure of either 35 psi, 2.5 bar (36 psi), 44 psi, or 51 psi. A P type XL (Extra Load) tire will have a max pressure of either 41 psi or 50 psi.

2) An LT tire will have a max pressure of 50 psi (Load Range C), 65 psi (Load Range D), 80 psi (LR E). etc. (with some exceptions)

3) It is common for tire manufacturers to put letters in the model name of the tire including LT, ST, HT, etc. This does NOT mean the tire is an Special Trailer, Light Truck, or Heavy Truck, etc. type tire. Those designation are in the SIZE - and in the case of ST and LT tires, they are explicit. (others, like P type, they are implicit.)

You may find some exceptions to the above as not everyone has a good understanding of how this works. For example, there are several tire manufacturers who put on the sidewall of their Standard Load P type tires: Max Load XXXX pounds @ max pressure 44 psi. This is sort of incorrect as the max load occurs at 35 psi, but 44 psi is the permissible max pressure with no increase in load.

Yes, I know it is confusing.

[BackOfThePack]

TurnThePage wrote:

CapriRacer wrote:

MFL wrote:
The door sticker is for best ride, but for towing heavy, you need to air up to get full use of tire load capability. Like mentioned full pressure in rear, and try about 42 in the front. A bit of trial, to know what handles best, after all hooked up and towing.

Jerry

Nope! That's not right.

The inflation pressure on the sticker on the door frame includes the max load (GAWR's) and unless specified otherwise, includes the towing limitations published by the vehicle manufacturer.

That may be technically accurate, but I know from plenty of experience that airing the tires up closer to their max, yields a significantly safer and more stable ride. My Ram 1500 recommends 41 PSI on both axles, which IS enough for stable and safe towing.

Put the tires to the value stated in the Load & Pressure Table (and vehicle manufacture range) according to Cat Scale axle readings. .

More than necessary DOES NOT make for better steering, handling or braking. . That problem is addressed by improving the pickup. Better shocks, polyurethane anti-roll bar bushings and a rear Panhard Rod. (HENDERSON'S LINE UP for a rear Trac Bar).

(Where a rear anti-roll bar doesn’t exist, choose the smallest. But upsize the front is then a requirement).

Using more tire pressure than NECESSARY to counter movement of the body against the suspension only makes loss-of-control MORE likely.

Dead-wrong approach.

Some sidewall movement flattens the edge at which tires lose their grip with tall aspect LT tires for given steering inputs. A warning. Weight-adjusted pressure IS the target.

Incorrect hitch rigging is the usual BAD BASELINE. Over inflating tires on top of that only makes a bad situation worse. But is the norm.

This is yet another aspect of using a Hensley-patent hitch. The trailer stays in CONSTANT alignment with the tow vehicle until TV steering inputs are introduced. The signals the driver is reading (the feedback) are not muddied by the trailer. The TV deficiencies are at the fore. Prominent. Obvious.

Getting passed close by a big truck at a far higher speed? With a Hensley you don’t feel it at the steering wheel until his bow wave hits the rear of the truck. Then you’ll know how sloppy that pickup really is. Body getting pushed sideways from the rear (and your too-long receiver length adding leverage) with tires straining against the suspension while you’re sawing at that wheel to keep the pickup ONLY in its lane. The trailer is wondering what all the fuss is about.

Address the real problem.

My pickup is nearing a quarter-million. Now finishing first replacement set of tires and nowhere near 4/32s. 50/50 Town & Country. Pressures don’t change hitched or unhitched as truck doesn’t change that much with 1,200-lb TW (450-lbs ea approx to Steer & Drive) when I connect the 35’ travel trailer.

Get the baseline first: WDH correct.

Test the tire pressure rise after Cat Scale check (having started with dead cold readings at dawn). 1.5-hrs steady-state Highway on cruise control. No lane-changing, accel or braking while below the traffic flow. Glide to an easy, easy stop at rest area. Check values. 7-8% rise is fine. More needs a bare PERCENTAGE increase. Least amount.

Find lowest. (Equalization value)

Your vehicles ride on AIR.

Completely empty or fully-loaded, you want THE RANGE of the tested MINIMUMS necessary.

( Note to CR: “payload”, “trailer tow capacity”, etc are advertising. Advice. Legal requirements are door sticker Axle/Wheel & Tire Limits).

.

.

[BenK]

There is a difference in tire classes, but since am not a tire engineer...don’t know the details in specifications

But...the fact that “P” class used on pickups/SUVs, has the RMA recommend their sidewall weight carrry information be reduced by 9%. Whereas “LT” class does not need to have it’s sidewall weight carry rating reduced...indicates a significant difference...or a 9% difference...

My guess is that there are either higher strength materials, more of it and the construction somehow different in some way.

Also, why the exact same OEM, model, size tire...but...the only difference being “P” class vs “LT” class will have the “LT” cost more and weigh more than the “P” class tire

[JIMNLIN]

I think Tireman9 has been banned because he has commercial adds ?? in his profile which is a big loss for all members. Other websites have no issues with him.

They are XL (extra load) tires, not LT

I wish we had more of the XL (51 psi) P tire sizes available for 1/2 ton truck/smaller trailer use.

[BenK]

Max tire PSI “used” to be fairly easy to decipher which class tire it goes with...similar to what a ‘half ton’/‘3/4 ton’/‘1 ton’ is...

Have eyeballed LT tires with max tire PSI of 35PSI (my 33/12.5R15LT C floatation tires) and passenger class tires with 44 PSI (my mini van’s).

Then the passenger class tire’s ‘XL’...fairly new to me and don’t know much about them, except that they are extra load rated...so ask did they do that with higher PSI and/or higher strength materials/processes ?

Even the OEM’s do NOT get it right all the time. We have DOT mandated tire pressure monitoring systems ever since Ford and Firestone got into a urinating contest over deaths/injuries from too low PSI on the door label

There is no one size fits all here...nor in tube socks either...

Changing tire size and class on any vehicle is re-engineering of that part of the suspension. Albeit not as major as changing other suspension components, but never the less important to the safety of the vehicle

The vehicle door label is the basis and for the tire specified by that OEM label. It does NOT apply to any change in tire class/size/etc. You have to re-engineer that application.

All of the OEM labels, specifications, published or listed on the internet are for the stock vehicle. Also part of the OEM’s contract to you, the owner/driver of what their product is rated for.

Too many here and other forums think ‘recommend’ as not really anything you ‘have’ to follow...legalese and it does have meaning. If you don’t follow the OEM’s recommendation, then why would the OEM provide warranty to you ?

Derogatory name calling is only a tactic to reduce someone else’s comments validity and the asking person (OP’s) risk management decision should take that into account.

Finally, the advisors here on these freebie forums has ZERO or NO skin in anyone asking’s situation. We do not provide a warranty nor anything else, as it is worth the money paid...

[Lynnmor]

They are XL (extra load) tires, not LT.

[Grit_dog]

^ Regardless of how you choose to interpret whatever you are interpreting, it is not a LT tire.
That very same size in a LT is an 80 psi tire with about 3000lbs rated capacity.

Heck, my wife's sports car has 51 psi tires.

[MFL]

JIMNLIN wrote:
CapriRacer and Tireman9 have both told us (for those that don't know them, both are tire engineers) for years a P metric tires max load capacity comes at 35 psi...even tho they may have a 44-51 max psi on the sidewall.
Higher pressures above 35 psi just stiffens the tires sidewall...but doesn't gain any more capacity.

And both engineers have also told us the OPs 275/55-20" tires has a 113T load rating/2535 lb capacity = a P tire.

Jim, not to discredit the tire boys, but the manufacturer of the OP's tires says they are LT tires, which I suspect is true with a max psi of 51 and 2,535 LR. A 44 max psi more likely to be P-rated. Many things change over time. I think the manufacturer's info should be current.

I better add: there is more than one version of that tire, so anything is possible, as to rating.

Whatever happened to Tireman9? Haven't seen him on this forum in quite awhile. Banned maybe? IDK, but seems I heard that?

Jerry