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Hoosier Racing Tire Sports Car DOT A7 Radials are Racetrack & Autocross Only tires developed for drivers who compete in autocross, time trial and hillclimb events in dry conditions where responsiveness and high levels of grip at lower operating temperatures are desirable. A7 Radials are also used for road racing on lightweight cars or when competing in cool ambient temperatures where Hoosier Sports Car DOT R6 Radials cannot be brought up to favorable operating temperatures.
WARNING: DOT labeled Hoosier Racing Tires meet Department of Transportation requirements for marking and performance only and are NOT INTENDED FOR HIGHWAY USE. It is unsafe to operate any Hoosier Racing Tire, including DOT tires, on public roads. The prohibited use of Hoosier Racing Tires on public roadways may result in loss of traction, unexpected loss of vehicle control, or sudden loss of tire pressure, resulting in a vehicle crash and possible injury or death.
And like all Racetrack & Autocross Only tires, A7 Radials are not intended to be driven in near-freezing temperatures, through snow or on ice. It’s also essential these tires be stored indoors at temperatures maintained above 32 degrees F.
Sports Car DOT A7 Radials incorporate a new tread compound designed to extend wear and useable heat cycles, as well as experience less “fall-off” during a long run and less degradation over the life of the tire (compared to A6 tires). The tread compound is molded into a slick tread design interrupted only by five-dash circumferentially oriented grooves alternating outboard and inboard. Beginning with a tread depth of 4/32″, they will not require shaving for competition, however they will benefit from a minimal scuff-in prior to their first runs.
The tire’s internal structure features a symmetric construction that uses two lightweight steel belts reinforced by a spirally wrapped circumferential nylon cap ply under the tread on top of two nylon cord casing plies. It features a rim recess design on all sizes. Additionally, its symmetric tread design and internal construction allows the tire to be mounted on either side of the car (and later be remounted inside out to further extend its life).
Because of the way tires are manufactured, taking measurements of unmounted tires does not provide an accurate comparison. Hoosier DOT-radials typically have very generous unmounted dimensions, so be sure to mount on appropriate-width wheels before making any judgment related to physical size.
The section width, tread width and shoulder profile of the A7 may differ from those of its predecessor, affecting the clearance between the tire and suspension components and/or body panels. If the intended application is an aggressive fitment with close tolerances, it is recommended to test fit a mounted, inflated tire to check for potential contact between the tire and vehicle before driving on the tires.
Founder at Tiresout. Used to be working as an engineer at Bridgestone Tires Akron Technical Center. The responsibilities included but were not limited to technical computing, indoor & outdoor testing of new tires.