4WHEELOFFROAD.COM 4-WHEEL & OFF-ROADOCTOBER 2019 71
NUTS & BOLTS
BY Trenton McGee
[email protected]TIRE TECH
Q
First off, I have to say thanks a lot for
all of your great and varied info. You
guys make it much easier for those of us
who haven’t tried most everything already
to make informed decisions on getting
into wheeling. It’s a little pricey to play
completely by trial-and-error in this hobby.
My question is, are the performance differ-
ences between similar class and design
tires from reputable manufacturers really
noticeable for most users (for example,
A/T to A/T or similar M/Ts)? And have there
been tires you really regretted? Not look-
ing to call out names, just anecdotes.
MATTHEW PULIZZI
Via [email protected]A
We appreciate the kudos, and you pose
some interesting questions. For start-
ers, we admit that some of us around here
put more stock in actual tread design and
compounds than others. Some of us swear
that they can tell a huge difference from
one tire to another, while a few of us think
that if a tire is round and holds air, it’s more
about the driver and the vehicle than which
tread shape or pattern does better in what
terrain. Tire manufacturers spend millions
of dollars developing and marketing tires,
and without question there is quite a bit of
science and technology behind a tread pat-
tern that works well and is quiet. But when
pitting two well-designed tires against each
other, determining which is better is going
to be dif ficult and will likely boil down to
deciding which is better in certain terrain
rather than overall performance.
There are some obvious performance
differences between tire types, such as an
all-season tire versus and all-terrain or a
mud-terrain. Each t ype of tire is designed
to excel in specific environments, and the
attributes that make it do well in one envi-ronment often come at the cost of some
performance in other environments. But
you’re specifically asking if we can feel a
difference in the same type of tire among
different manufacturers.
So for example, can we tell a real perfor-
mance difference between the Toyo Open
Country A/T and the BFGoodrich All-Terrain
T/A KO2, and do we think that the average
user could as well? Unfortunately, there’s
no simple ans wer to the question because,
for starters, there’s such a broad range of
tires out there. We’d be willing to bet there
are probably over 100 tires on the market
that are classified as all-terrains alone.
With that kind of variety you are sure to
have tires that clearly perform better than
others, but where and in what conditions?
We would need to narrow the field some-
what and perhaps separate well-known
brands that have been around for a long
time from the no-name bargain tires that
we’re seeing more and more at small, inde-
pendent tire shops. You get what you pay
for, and our limited experience with the
no-name Chinese import stuff is pretty con-
sistent with what you’d expect. With repu-
table brands, the bar is quite a bit higher
but still no easier to define.
Among the reputable brands, for sure
we have experienced tires within the same
class that were amazingly quiet on the
street and performed well off-road, and
we’ve also had tires that were annoyingly
loud on the street and sucked off the pave-
ment. Luckily the market seems to sort
them out because the bad ones usually
aren’t around very long. One of the author’s
personal pet peeves is tire balance, and
there are a couple of very well-known man-
ufacturers who shall remain nameless that
seem to be incapable of making a round
tire. Some tires excel in the dirt but at the
cost of road manners, and vice versa.
It’s really more about what your primary
uses are and your priorities in terms of
which types of terrain you need the tires
to perform well. A desert guys doesn’t care
about snow and ice performance, while a
snow wheeler probably isn’t as concerned
about puncture resistance. This is why we
always encourage people to talk to their
local wheelers and off-road shops. There’s
a reason we see a lot regional popularity
among tires.
With all of this said, at the end of the day
it all boils down to opinion, and you know
what they say about opinions. How’s that
for a convoluted non-answer to a complex
question?OLD-SCHOOL SPARK CONTROL
Q
For many years the way to control
spark-related engine knock was to
downshift or ease off the throttle. Modern
computerized engines now control it by
simply retarding the timing. With that
in mind, I’m tempted to install a manual
spark advance lever on the steering col-
umn of my vintage 4x4. It’s powered by a
Chev y V-8, and it wouldn’t be overly com -
plicated to link a manual spark control to
the vacuum advance port on the distribu-
tor. Do you know of anyone selling a well-
engineered kit to do the job? With manual
spark control it would be possible to dial-
in optimal spark advance for virtually any
driving condition on- or off-road.
DOUGLAS C.
Via [email protected]A
Not too long ago we bought a Jeep
with the exact setup you describe, and
although it was old, we were shocked that
the timing control was still fully functional.
While it’s less hassle to just set the timing
where the factory recommends it, should
you want to optimize performance and fuel
economy, having manual spark control on
an older vehicle isn’t a bad way to go. You
can advance spark for better performance
in unladen situations, and retard it when
towing heavy loads or going up a long hill.
You are correct that modern computer-
controlled engines are constantly chang-
ing timing curves for optimum performance
and fuel economy.
Some aftermarket fuel injection systems
will mimic modern computer control s in
regards to timing, but if you want just plain
old manual controls, MSD Ignition (holley.
com/brands/msd) offers an adjustable
timing controller that allows to advance or
retard timing up to 15 degrees. The control-
ler can only be used with one of MSD’s igni-