BY KEVIN HETMANSKI
Just about anyone can take a truck and crawl over
some rocks, but the ones who dial in their rigs can go
further and make the impossible possible. Getting the
setup on your tires and rims is one of the most important parts of your truck to tweak. Selecting the best
tire tread and correct compound is important, but
there are a few additional things you can do to optimize performance. These tips may or may not be
helpful on the specific terrain you’re driving on, so
don’t be afraid to experiment.
Today’s soft compound tires require foam inserts to help them keep
their shape. In most cases, the foam inserts make the tires too stiff
for crawling and don’t allow the tire to conform to the rock’s surface.
You want the tire to be flexible yet stiff enough support for the tire
to prevent it from folding over. A lot of guys cut their inserts in a star
type pattern to make that happen. Making this modification is easy.
Mark the foams with the desired pattern, and carefully cut the sections out using a sharp hobby knife. How much or how little foam you
remove will be largely based on the flexibility of your tires. Softer
tires require more foam to be left for support.
A key to good traction is to have the tread of tire to be generally as
flat as possible. A larger contact surface means more traction. An
insert that is wider than the tire will distort the tread of the tire and
potentially reduce the contact patch. You can eliminate this problem
by cutting the foam insert so that it’s the same width as the tire.
I used some of the techniques
shown in this article when building
my own rock crawler.
Above: cut your inserts in a star pattern
to soften up the foams. This will allow
the tire to conform to the rocks and still
give it enough support. Left: memory
foam is the latest trend in tire inserts.
The latest trend in foam inserts is memory foam. It’s available from Kreepy Krawler Designs and RCP Crawlers. Since
the memory foam is denser than standard foams, it adds
weight to the tires to increase traction. Memory foams are
also often run without any modifications such as cutting into
a star pattern.