Tires: P vs LT-rated ?

Assuming the same size, which ones are more appropriate for my Toyota Tundra
4x4: P or LT-rated? I haul a load quite infrequently. I also have infrequent
(and mild) off-pavement ventures. Wet/snow performance is important, as well
as dry, needless to say, on a year-round tire. (I am considering Bridgestone
Revo 265/75R16 for now which comes in both versions.)

1. P-rated are cheaper and, since I rarely carry a load, seem appropriate.
But how about the wear characteristics? LT has somewhat deeper tread which
suggests longer wear, but does it give me that much of it to justify the
extra cost? Deeper tread is also better for snow/wet traction, I assume (for
awhile, at least, until it wears even with a P-tire).

2. On the other hand, since LT is designed to carry a load, it must be more
rigid, thus producing more noise/vibration. I am about as much concerned
about ride comfort on dry as the wet/snow performance.

3. Which one of these has smaller rolling resistance, i.e. gives me greater
MPG and by how much?

Thanks in advance!

The Revo is an awesome tire and will give you great wet/snow traction. They
are the highest rated AT tire out there. You would be best to go with the
'P' rated Revo's for what you want, or if you really want to get LT tires,
get the 'C' load rated ones. They are the best compromise between durability
and ride. I don't think either one will make more road noise than the other,
that is mostly determined by the tread design.
I have LT265/75/16 'D' rated tires on my Tacoma, they are the Nitto Terra
Grapplers. I immediately saw a 1-2mpg drop after putting them on, but
managed to get it back by running them at 40psi front and 35psi rear. This
is because the LT is heavier that the P in the same size, creating more
rotational mass. It is most noticeable on initial acceleration. You might
not notice any MPG or acceleration difference if you have the V8 engine, but
my V6 can feel it. The 'D' load rating can safely run 65psi cold. The ride
is definitely stiffer, but I actually prefer it that way. When running them
at the recommended psi of 30 front and 26 rear, I couldn't tell a ride
difference between the stock P rated tires I had on before.
The LT does have a slightly deeper tread (1/16") so you should get better
mileage if they are properly inflated and rotated. I have 10k on mine and
they still look new, and have a 500 treadwear rating, as do the REvo tires,
which should give you 50k easy.
You can check out the different specs on the Revo here....
http://www.tirerack.com/tires/Spec.j...Com pare1=yes

> Assuming the same size, which ones are more appropriate for my Toyota
> Tundra
> 4x4: P or LT-rated? I haul a load quite infrequently. I also have
> infrequent
> (and mild) off-pavement ventures. Wet/snow performance is important, as
> well
> as dry, needless to say, on a year-round tire. (I am considering
> Bridgestone
> Revo 265/75R16 for now which comes in both versions.)
>
> 1. P-rated are cheaper and, since I rarely carry a load, seem appropriate.
> But how about the wear characteristics? LT has somewhat deeper tread which
> suggests longer wear, but does it give me that much of it to justify the
> extra cost? Deeper tread is also better for snow/wet traction, I assume
> (for
> awhile, at least, until it wears even with a P-tire).
>
> 2. On the other hand, since LT is designed to carry a load, it must be
> more
> rigid, thus producing more noise/vibration. I am about as much concerned
> about ride comfort on dry as the wet/snow performance.
>
> 3. Which one of these has smaller rolling resistance, i.e. gives me
> greater
> MPG and by how much?
>
> Thanks in advance!
>
>

I've been considering the same question. 265/75-16 tires have a slightly
larger outside diameter than 265/70-16 tires, so you'd feel the loss of a
small amount of power. Gas mileage might improve unless the higher
"effective" gear ratio causes your transmission torque converter to unlock
more often. 245/75-16 tires are about the same outside diameter as
265/70-16, but many folks don't like the skinny look.

I think I'll get P265/70-16 tires. That was Toyota's choice, and they
likely know something I don't about tires for their trucks--although I
disagree with them about inflation pressure, and we all know how they went
cheap with the OEM Dunlops and Bridgestones.

For slippery road traction, I like to have my tires siped when they're about
half worn. I buy new tires with good factory siping. When there's about
7/32'nds of an inch of tread remaining, I have the tire shop use their 5/32"
sipe cutter. By then, the rubber is hardened from many miles of hot road
surfaces & friction, the edges of the tread blocks are worn rounded, and
often the factory siping is worn away.

Ken

"J.Smith" > wrote in message
...
> Assuming the same size, which ones are more appropriate for my Toyota
Tundra
> 4x4: P or LT-rated? I haul a load quite infrequently. I also have
infrequent
> (and mild) off-pavement ventures. Wet/snow performance is important, as
well
> as dry, needless to say, on a year-round tire. (I am considering
Bridgestone
> Revo 265/75R16 for now which comes in both versions.)
>
> 1. P-rated are cheaper and, since I rarely carry a load, seem appropriate.
> But how about the wear characteristics? LT has somewhat deeper tread which
> suggests longer wear, but does it give me that much of it to justify the
> extra cost? Deeper tread is also better for snow/wet traction, I assume
(for
> awhile, at least, until it wears even with a P-tire).
>
> 2. On the other hand, since LT is designed to carry a load, it must be
more
> rigid, thus producing more noise/vibration. I am about as much concerned
> about ride comfort on dry as the wet/snow performance.
>
> 3. Which one of these has smaller rolling resistance, i.e. gives me
greater
> MPG and by how much?
>
> Thanks in advance!
>
>

Thanks for input, Dave!
I think you are right -- I will stick with the P-rated ones for now,
considering my application.

> I've been considering the same question. 265/75-16 tires have a slightly
> larger outside diameter than 265/70-16 tires, so you'd feel the loss of a
> small amount of power.

Yeah, I thought about that, too, but I think on a (mostly) unloaded V8 you
would barely notice it, if at all.

> Gas mileage might improve unless the higher
> "effective" gear ratio causes your transmission torque converter to unlock
> more often.

You mean sooner-than-usual downshift? (What does "torque converter
unlocking" mean?)
I haven't even thought about that. You think on a 3% larger tire (which
265/75 is to 70) that would be significant? (How many MPG might I lose on
average on a level road?)

> I think I'll get P265/70-16 tires. That was Toyota's choice, and they
> likely know something I don't about tires for their trucks--although I
> disagree with them about inflation pressure, and we all know how they went
> cheap with the OEM Dunlops and Bridgestones.

I would go with 265/75-s. They are a little beefier and some $20 cheaper as
well (larger but cheaper, go figure), but COSTCO (which is the cheapest
source I was able to find) won't install them, 'cause they are over the OEM
specs. So, I am scratching my head, should I buy them and install at another
place thereby waiving the road hazard, or get the more-expensive (and
less-desired) 265/70s?

> For slippery road traction, I like to have my tires siped when they're
about
> half worn.

That's interesting! Never heard of anyone doing that. How much such a
service costs? I hope it's not too expensive.

Thanks, Ken!

> You mean sooner-than-usual downshift? (What does "torque converter
> unlocking" mean?)

The torque converter on almost all newer vehicles locks the two halves at
highway speeds to increase gas mileage. Its acts the same as a manual
transmission when the clutch is fully engaged so there is no slip between
them, the slip in an auto transmission being the fluid.
You can accelerate with it locked, very gently on a flat road. Too much gas
will make it unlock, which feels like a light downshift.

> I haven't even thought about that. You think on a 3% larger tire (which
> 265/75 is to 70) that would be significant? (How many MPG might I lose on
> average on a level road?)

You should actually get slightly better mileage with the larger tire because
the wheels are now turning less revolutions per mile at the same speed. If
the tires are somewhat heavier than the stock tires, this usually balances
it out. Remember to add 3% to your mileage when figuring MPG. 300 miles is
actually 309.


> I would go with 265/75-s. They are a little beefier and some $20 cheaper
> as
> well (larger but cheaper, go figure), but COSTCO (which is the cheapest
> source I was able to find) won't install them, 'cause they are over the
> OEM
> specs. So, I am scratching my head, should I buy them and install at
> another
> place thereby waiving the road hazard, or get the more-expensive (and
> less-desired) 265/70s?

265/75 are cheaper simply because they are a much more popular size. Many
full size trucks and SUV's come with this size stock. If you have a Discount
Tire store near you, go to them and tell them what quotes you have recieved
from other stores. They will price match to get your business. The store I
got mine at even installed them for $1 per wheel less their own wholesale
direct price from the internet, after you figured in mounting and balancing,
which is usually $1/inch. A 16" wheel tire is $16 to have mounted/balanced.

Thanks, Dave, for explaining the converter locking (and other stuff)!

> If you have a Discount
> Tire store near you, go to them and tell them what quotes you have
recieved
> from other stores. They will price match to get your business. The store I
> got mine at even installed them for $1 per wheel less their own wholesale
> direct price from the internet, after you figured in mounting and
balancing,
> which is usually $1/inch. A 16" wheel tire is $16 to have
mounted/balanced.

I certainly have a Discount Tire closeby (It's called America's Tire here)
and they do price matching -- only problem, not on Bridgestones, which is a
special order item. (Damn!)