Toyota Trucks: More tire questions

"H.B. Elkins" wrote: 

The 31x10.50R15 are Light Truck Tires. The P265/75R15 are Passenger Car
Tires used on a light truck. The Light Truck (LT) Tires have a thicker
carcass and require higher pressures for a given load to reduce flexing
and prevent heat build-up. The maximum load carrying capacity and
maximum inflation pressure of Light Truck Tires is determined by the
load range (C, D, E, etc.). P metric tires for a given size all have the
same maximum load (but not necessarily the same maximum pressure - extra
load tires have higher maximum inflation pressures, but the same maximum
load).

A standard load P265/75R15 tire has a maximum inflation pressure of 35
psi. The maximum load at this pressure is 2365 lb. when used in light
truck applications (this will not match the maximum load of 2601 lb
listed on the side wall - P series tires are derated when used on light
trucks). The overall diameter of this size tire should be approximately
31.7"

A 31x10.50R15, Load Range C Tire is rated to carry 2250 lb when inflated
to 50 psi. The overall diameter of this tire is 30.7".

So if you substitute the LT tires for the P series tires, your
speedometer should read higher than the actual speed (62 indicated at an
actual 60). The LT tires also require much higher inflation pressures.
This combined with the stiffer carcass will result in a much stiffer
ride. You should also expect the gas mileage to suffer slightly because
of the heavier tires.

Ed

"C. E. White" <com> wrote:
 

All this info is making my head spin.

I'm still no closer to finding something to put on my truck to replace
the factory Firestone Wilderness AT II tires.

I'm looking for something that's quieter than those factory tires. I
cannot find P265s anywhere that don't have those huge "mudgrip'
treads.

I can't really find any info that tells me how easy it would be to
readjust the speedometer if I opt for P225s, which is what is listed
on the door plate of the truck and in every place where I'm asked to
give my truck model and provided a list of recommendations.

And I don't want to spend a fortune ;-) and would love to buy at
Wal-Mart or Sam's Club where lifetime balance and rotation applies, as
well as a good road hazard warranty.
+++++++++++++++++++++++++
H.B. Elkins -- Beattyville, KY
http://www.millenniumhwy.net hbelkins(at)mis.net

"There's no doubt he's the best race driver in the world."
--Dale Jarrett, on the late Dale Earnhardt

Go Big Blue (Kentucky Wildcats)! Go #15 (Michael Waltrip, NAPA Chevy)!

To reply, just remove the restrictorplates...
++++++++++++++++++++++++++

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In article <newsguy.com>,
mis.net (H.B. Elkins) wrote:
 


Holy jeebers, would you please just make up your mind!

Speedo calibration is probably electronic, which would most likely mean
a trip to the shop and a little trial and error unless they have some
presets built into the speedo circuits to account for different tire
sizes that are installed in the factory. Come to think of it, that
makes sense because the don't want to have to manually calibrate all of
those vehicles as they roll off the line.

Why not call the dealer and ask a technician? Or why not ask the
question in a new thread---there's a Toyota Tech that reads this
newsgroup pretty frequently.

I'll send you an email with the name of my friend and you can call him
if you want.

--
Sean Elkins Owenton, KY RKBA

Being a talented actor or musician doesn't make some
drop-out's political ideas more valuable or enlightened
than mine.
**************************************************

If you have access to a GPS unit, you can check your speedo. You need a
straight section of highway. Drive at constant speed, say 60mph, and see
what the GPS says. Or you can use the GPS as a speedo and see what your
speedo says. I did this for various speeds and made a little chart. After
a couple of days of driving I didn't need the chart.
You really should have a buddy along to run the GPS so you can pay attention
to the road.

Bearman

"H.B. Elkins" <mis.net> wrote in message
news:newsguy.com... 

Yokohama Geolandar HT tires are very nice all-weather, quiet, and not so
pricey....


"H.B. Elkins" <mis.net> wrote in message
news:newsguy.com... 

"H.B. Elkins" wrote:
 

According to the 2000 edition of the Tire Guide, your truck should have
had P225/75R15 tires unless it had the Value Edition Package, in which
case it would have had the P265/75R15 Tires.

The difference in tire diameter is not minor:

A P225/75R15 Tire will have a diameter of approximately 28.29 inches.
A P265/75R15 Tire will have a diameter of approximately 30.65 inches.

Assuming the speedometer was correct when reading 60mph with the
P265/75R15 tires, then you will actually be going only 55 at an
indicated 60 if you change to the P225/75R15 Tires. Your dealer should
be able to tell you how difficult it is to recalibrate the speedometer.
If all else fails see http://www.4wheelerssupply.com/Products_01762/ .

If you are looking for quieter tires in a given size, go to
www.tirerack.com and search on the tire size. See
http://www.tirerack.com/tires/Compare1.jsp?startIndex=0&width=265%2F&ratio=75&di ameter=15&search=true&pagelen=20&pagenum=1&pagemar k=1&x=13&y=8
Tire Rack lists 13 tires for the P265/75R15 size. Several of these have
highway tread. Of the 122, I personally would choose the Dunlop Radial
Rover A/T or the Yokohama Geolandar H/T-S G051.

Since the P225/75R15 Tires were available on your vehicle, it is
probably OK to change to this size. However, this size tire has a
significantly lower maximum load rating (1874 lb for the 225s vs 2469
for the 265s). Persoanlly I would not make the switch to the smaller
tires.

Ed

I have an 03 extcab Taco. It came with P225 tires. I had them taken off
within 24hrs of getting the truck and put on the TRD wheels with BFG AT's,
LT265's. I recently discovered the exact amount my speedo is off...I got a
GPS for Christmas and was able to compare. When speedo says 110kph, my GPS
says 112.5-113kph. I am figuring that after going 100kms, I've actually gone
112.5kms.

Its not much of a difference to me to want to adjust the speedo. Some
vehicles are off by that much anyway.