 
|
| |
|
GENERAL GUIDELINES
ON SIPING & GROOVING HOOSIER SPRINT TIRES
|
|
3-15-2002
|
With the huge success of Hoosier sprint tires on dirt tracks
throughout the world it's not surprising we receive many inquiries on
how/when to groove tires. The following text is intended as merely a
guideline based on the experiences of our staff over the years. We acknowledge
there will be other opinions that may be as successful or possibly
even more successful than those set forth below. There is no one
"right" method. As racers, you may want to use the
information as a starting point and modify your technique based on
your own experience and success at the track you are racing.
|
|
SIPING ONLY: Siping is a technique first
patented in the 1920's by a man named John Sipe who came up with the idea
of putting razor cuts in his shoes to give him better traction. When
applying this technique to a dirt sprint tire, siping will do many
things. First, this will help the tire build heat quicker which will
help the tire "fire" better. Siping will also dissipate heat
when the tire gets to operating temperature and the sipes open up. If
you are using a fairly hard tire, siping will help create a
"graining" effect which will help keep the tire from
"sealing" over. The only sprint compound we do not normally
recommend siping is a D10 tire because it is already very soft and may
result in "tearing" of the tread blocks and will result in
loss of traction. As such, you rarely see Hoosier sprint tires siped
for qualifying since the D10 compound is normally the qualifying
compound. Also, never sipe a tire more than half the depth of the
tread block. Any deeper than half the depth of the tread block may
cause the sipes to rip or chunk out. How much you sipe a tire will
come from your own experience through trial and error. Also, like all
good racers, pay attention to what techniques your competitors are
using. They may have learned something you have yet to
experience.
GROOVING ONLY: We recommend
grooving a tire if the track is very wet and heavy or if the track is
a hard surface with a lot of loose dirt blowing across the surface.
Grooving will help channel the dirt out the tire to help maintain a
good contact patch between the tire and track surface--just like the
grooves in your street tire which help keep your car from
hydroplaning. Grooving will also create more edges for better traction
or grip. Just as with siping, how much you elect to groove your tires
depends on what you have experienced in the past along with watching
what the top finishing drivers are doing as well.
SIPING AND GROOVING: Combining both
siping and grooving is normally done in both heat and feature races.
You may need the grooves for cleaning but yet you also need to do some
siping to help the tire "fire" and to allow the tread
surface to properly "grain".
SIPING
|
|
Generally, the grooving blade is
reversed to result in two independent cutting blades. The depth should
be set no deeper than 1/2 the depth of the tread blocks. Deeper than
1/2 the depth may cause individual tread blocks to rip or chunk out.
When setting the depth of the blades for siping, place the siping head
on the tread block and visually adjust the depth to 1/2 the thickness
of the block. |
|
|
|
|
Proper siping of this tire has resulted in a very
nice texture or grain to the tread surface. The siping allowed the
tire to "fire" quickly on starts or re-starts and as the
race went on, the sipes allowed heat to be expelled which resulted in
less chance of blistering. |
 |
|
|
|
A sipe is simply a razor thin cut or slit in the
rubber tread block. |
 |
|
|
|
GROOVING
|
|
Straight grooves work best for forward bite. We
recommend no wider than 3/16" wide of grooves. Wider than this
may tend to cause the tread block to rip or peel back. |
 |
|
|
|
When using a very hard compound, you may want to
1/4 groove the tread blocks allowing for a greater degree of
"cleaning" grooves and more edges for increased traction.
Usually the tire is cut vertically and then horizontally or vice
versa. |
 |
|
|
|
Grooves can also be cut at angles. Angled grooves
will result in a combination of increased side bite as well as
increased forward bite. |
 |
|
|
|
Unlike siping in which you should go no deeper than
1/2 the depth of the tread block, grooving can and generally is the
full depth of the tread block. Also, the
"hole" in the tread block(s) is called a "heat dispersion
vent" which serves to reduce the chances of blistering. |
|
|
|
|
Proper grooving and siping techniques will ultimately result in a
better performing sprint tire which will in turn result in higher
finishes. |
|
|
|
|
| |
|
Copyright ©
2002 Hoosier Racing Tire Corp.
All rights reserved.
Do not duplicate or redistribute in any form.
|
|
HOME
|
|