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| 1845 N Wayne Road Westland MI 48185 734.722.7223
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Bias Ply Definition:
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Bias ply tires have the cords criss-crossed across
the tire from one bead to the other. The cords make
an angle of between 32 and 40 degrees with the
center line of the tread. Bias ply tires will typically
have stiff sidewalls and flexible tread face.
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Radial Ply Tires:
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| A radial tire uses a cord angle of 90 degrees. The cords run from one bead to the other directly
across the tread. Additionally, a radial tire has a belt
overwrap under the tread surface, and can be made
of various materials including fiberglass and steel
mesh. The belt overwrap of a radial tire causes less
tread distortion under load and more sidewall
distortion. |
Belted Bias Tires:
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| Belted bias tires are a hybrid combining bias plys
with the radial belt overwrap under the tread
surface. This type of tire has the excellent
feedback of the bias and the reduced tread
distortion of the radial. racing radial tires are
very close to this design. |
Cantilever Sidewall Tires:
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The cantilever sidewall is very stiff and helps support the tread. This allows you to use a tread face which is as
wide or wider than the rim size. This type of tire is best suited for cars with rim width restrictions. You are
limited to using a 15 x 7 inch rim. The "e;Hoosier Road Race" 23.0 X 9.5-15 tire has a tread width of 9.2".
Normally you wouldn't be able to put 9.2 inches of tread on a 7 inch wide rim.
*Please Note: This does not come without a cost.
usually the section width of a cantilever sidewall tire is larger than non-cantilever tires. Also, the transient
response of the cantilever tire is less than non-cantilever tires (provided the non-cantilever tire is on the proper
rim). |
Dimensional Terms Defined:
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All measurements are in inches.
Specification Rim:
This is the rim size used to obtain the measurements in the specification tables.
If your rim size is different, add or
subtract .2" from the section width for each 1/2" change in the rim width. Example: You're going to mount a
P245/45ZR-16 on a 9" wide rim. The specification sheet indicates a 10.0" section width on a 8.0" rim. The section width of this
tire on a 9" rim would be 10.4".
For shipping purposes we use US pounds. The shipping weight of a tire is rounded up to the nearest whole pound.
Suggested rim widths:
This is the rim width to use on vehicles of reasonable weight. Light cars can use the low side of the recommendation
and occasionally smaller. Heavy cars (most American iron) and users of bias ply tires should use the widest rim
possible.
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Rebound
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The ability for rubber to retake its shape after being compressed.
Normally low rebound
characteristics = high traction. |
Heat Curve:
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| The heat curve of a compound can predict how a tire will react during competition. It is most useful during manufacturing for
quality assurance. We use it to compare different compounds and brands of tires.
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Pyrometer:
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| A Pyrometer is a device which measures the temperature of the tire tread. The two most common designs are the probe and
infra-red. The probe design is inserted just under the surface tread, the infra-red doesn't touch the tire and reads the surface
temperatures. |
Durometer:
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| A durometer is a device which measures resistance to compression. The device is typically used by dirt track racers more than
road race/autocross. |
Contact Patch:
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| The tire contact patch is the part of the tire that touches the road. On tall tires the contact patch is longer than wide. On short
tires the opposite is true. The contact patche ratio of "length to width": is called the aspect ratio. Aspect ratio is one determining
factor of the slip angle.
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Slip Angle:
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The slip angle of a tire is the angular difference between the wheel direction and the contact patch direction. Design
characteristics of tires that affect slip angles are: compound, cord bias angle and construction, cord material and side wall height.
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