Re: Tires for scout

[jlandry@domain.elided (John A. Landry)]

On Wed, 26 Nov 1997 10:34:32 -0500, David Nedved <david@domain.elided> wrote:

>I have the opportunity to buy some tires for my scout at a reduced price,
>long story, but the tires are listed by the "technical name" ie P235/75R15,
>etc.

That is a "metric" tire size... nothing technical about it really.  If I'm
not mistaken, it means this: P = passenger car tire, 235 = 235 mm section
width, tire height is 75% of section width, R = radial construction, 15 =
15" rim diameter.

>I would like to get some 31" or 33" tires, and I have already done enough
>lifting to accomodate them, and there are lots of tires for me to choose
>from, however I don't know what "technical name" 31" or 33" would translate
>to.  Could someone who knows be kind enough to tell me the numbers of some
>31" or 33" tires which would fit fine on my rims?  The example above
>P235/75R15 is what I currently have.  The tires I can choose from are BFG,
>Uniroyal and Michelin.  Any suggestions of which particular models are good
>on and offroad (maybe 75%/25% usage) tires would also be appreciated.

You'll find that most larger truck type and off-road tires use a different
sizing designation than the metric type you currently have.  You'll be
looking for something like 10.5x31-R15LT.  This means: 10.5" tread width,
31 = 31" outside tread diameter, R = Radial, 15 = rim diameter, LT = Light
Truck use.

You simply have to decide how tall of a tire your truck can handle.  You
need to consider your gearing, engine power, suspension height, etc.  Once
you decide how tall, then you can also decide on how wide you want the
tread.  People have very differing opinions on what's best, but generally
wider tread means less weight per square inch applied to the contact patch.
This can be good or bad depending on what type of off-roading you do.  Some
feel that a tall narrow tire is good for best traction in mud so you can
"dig" down through the goo to solid ground.  Wide tires are generally
better for driving on softer unstable surfaces like sand.  Wider tires can
interfere with steering components, and place a higher load on the power
steering pump.  If you have stock 7" rims, then 10.5" tread width is about
as wide as you'll want to go, unless you get wheels a bit wider.

Be aware that the actual tire sizes may differ quite a bit from the size
designation.  I have 10.5x31-R15 Dunlop Radial Mud Rovers, and they started
out 30.8" in diameter when new.  Some brands of tires using the same size
designation are closer to 30" in diameter when new.  Most manufactures can
supply specifications on actual tire size before you buy.

The other consideration is how "aggressive" of a tread design you want.
Many folks choose "all-terrain" type tires because they want better fuel
economy on the higher.  They give up some traction off-road as a result.  I
run a pretty aggressive tread on my tires even though most of my driving is
on-road, simply because I want good traction when I do head off-road and
don't want to own two sets of tires.

If you're an occasional off-roader (like me) and don't do aggressive
trails, then 10.5x31-R15's would be an acceptable size upgrade.  This size
rarely causes any steering or suspension problems (even with stock height)
and is still a bit bigger than what you have now.  Prices are pretty
reasonable on this size too.

Happy shopping,

John
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