Tire ply for 285/70/16 Nitto Grapplers?

Learned something new today, always thought 10 P.R. meant 10 plies.

 

E Rated over here

 

It would if you were buying bias ply tires even in 2020.

There are some, Interco (Super Swampers for example) still makes a few models in bias ply construction that are DOT approved:
https://www.intercotire.com/tires/type/specialty_light_truck_off_road

Or if you're after vintage tires there's these pizza cutters:
https://www.stausaonline.com/tires/sta-super-traxion/

 

Interesting, just googled about all that. So my C loads have same plies as SL rating then?

 

Your sidewall should tell you exactly what your tire has. But yeah, C/D/E rated doesn't necessarily mean more puncture resistance. I mean, practically, it sometimes sorta does, but puncture resistance has more to do with how the tire is constructed. Buying an E-rated tire doesn't guarantee more puncture resistance. Those ratings are mostly for how much air pressure the tire can handle, which relates to how much weight they can handle.

 

They have the same number of actual plies in the tire construction, although the materials or technique used are necessarily identical. Like has been mentioned the polyester fibers or thickness of the rubber might have to be different to hold the air pressure. So it's not a simple comparison to make. When they went to radial construction the ply "rating" is implied that they have the same capability as a whatever bias ply tire did is all. Maybe years ago that they did actually have to use more plies in LT tires, like maybe 3 or 4 to get an E-rating, I couldn't say.

 

/thread

 

My C loads say 6P.R. , so it has 6 plys?

 

Seriously, why are you plagiarizing me? Nice to see someone else here with real tire knowledge.

 

No. 6 PL = Ply Rating.

Most tires have 2 ply sidewalls. Some have 3. Construction, stiffness, etc. of those plys varies by load range.

 

It’s true that tires add rotational inertia but if calculate how much it is, it’s only like 8% of the total inertia of the truck. I have a reference but it’s not handy right now.

 

I agree with much of what you said and also find quite interesting that you have experimental evidence that load rating is not well correlated with rolling resistance. I would guessed the opposite.

Most of my experience comes from bicycle tires but I’m guessing there is significant overlap with automobile tires. Low rolling resistance bicycle racing tires tend to have a different rubber compound and also less rubber than a touring or commuting tire. A racing tire is paper thin and super flexible. A touring tire is a bit thicker and less flexible; more durable feeling.

Because rolling resistance is caused by energy converted to heat when the tire flexes, I would expect tire thickness and rubber compound to be big factors.

I think rubber thickness tends to correlate well with tire weight and so people fixate on the weight of the tire when talking about fuel economy when in fact it has more to do with the amount of rubber, type of rubber, and perhaps tread design.

For whatever reason, tire manufacturers do not publish rolling resistance specs; not even racing bicycle tire manufacturers where it is a big concern.

 

Just get SL rated tires unless you are willing to trade ride comfort, acceleration, and fuel efficiency for looks. Those tires are overkill for a Tacoma driving on the road. I have E-rated LT tires but it’s because I do drive off road and the tire size and type I wanted only comes in E rated LT.

 

I agree that there is no magic formula for load and puncture resistance. No matter what tire you have, sidewalls are always vulnerable, however, in general a higher load rated tire will give you more sidewall strength, it is purely physics, thus the requirement when wheeling in some areas for a C rated tire or above. The other thing that is a disadvantage with an SL rated tire is with airing down. At first glance you would think that the SL tire with a lower working psi and softer sidewall would work better to provide traction aired down, however, my experience has been the opposite. The relative psi on a higher rated tire will maintain integrity and traction through a wider psi range, provide better surface traction, and be far less likely to sustain a sidewall puncture or a pinch flat running at an optimal level. Airing down appropriately not only helps the tires and your truck, but it also keeps the trail in better shape by providing a big improvement in traction.

With everything being said, there is no substitute for experience, regardless of what tire you are running. It's invaluable to get to know how your tires react to the changing terrain and conditions at different psi, and driving appropriately for the conditions and vehicle setup go even further in avoiding tire issues. There are those that maintain that SL tires are more than adequate for off road use, but when running in remote areas without support, I will take a E load tire every time.

 

I'm surprised there are those that would argue that SL is better for off-road use. As you mentioned, I don't really want to be airing down an SL tire. (and then theres the XL tire - I don't think they are built any differently than an SL, are they? I can't say I know.)

The only justification for an LT tire on such a light vehicle, (IMHO) like a Tacoma, is for the more serious off-road adventuring, especially if the vehicle has had weight added to it - and well, if you really want the look of a big chunky tire, thats as good a reason as any, I suppose.

But how many people get told that they need an LT tire, even though they rarely if ever leave the pavement, and then they complain endlessly about how rough it rides, and the tire noise, etc.,? The value in this discussion, I think, is helping everyone make a more informed decision to best fit their needs. Right?

 

Diameter is the worst offender, because the radii are squared in rotational inertia formulas.

 

They’re all called grappler which one are you looking at? But if you’re mostly hwy , no need for a c or e.

 

I'm aware. Here is the rotational inertia post I was referring to.

https://ecomodder.com/forum/showthread.php/effects-wheel-tire-rotational-energy-25197.html

And here is document on tires and fuel economy.

file:///Users/gudu/Downloads/811154.pdf

 

This article/calculator is a little more comprehensive.
http://hpwizard.com/rotational-inertia.html#weight

 

C,D,E are going to be stronger than SL or P.
SL and P have an equivalent strength rating of a 4 pLy. Sure there are no plys anymore but its a measure of strength. Plus their tread depth is shorter usually.