The Proxes RA1 is Toyo's Racetrack & Autocross Only tire developed for drivers looking for street-legal circuit tires that combine consistency, durability and competitive times. Proxes RA1 tires are designed to provide an uncommon advantage to cost-conscious competitors who demand quick lap times and long tire life from their racing tires.While Proxes RA1 radials meet DOT requirements, they are not appropriate for highway use. Proxes RA1 radials are not recommended for driving in wet conditions when shaved or worn where standing water is present and there is the risk of hydroplaning; drivers should drive cautiously at reduced speeds if they encounter these conditions. And like all Racetrack & Autocross Only tires, Proxes RA1 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 15 degrees F.Proxes RA1 tires feature a soft but durable R-Compound that is tolerant to repeated heat cycles. This compound is molded into a symmetric stepped tread design that delivers competitive handling and performance. When new with 8/32" of tread depth, the tire features an independent tread block and groove arrangement that emphasizes wet traction. Shaving to reduced tread depths increases direct contact with the track to improve dry traction. Dry traction is enhanced at 6/32", lateral grooves disappear at about 4/32" and only two central circumferential grooves remain when worn to 3/32" to deliver the best dry traction.The tire's internal structure features an advanced competition modified radial construction for driving hard through the corners and accelerating quickly onto the straight-aways.Toyo Tires recommends the following general set-up guidelines for the Proxes RA1:Operating Temperature: 160°F to 220°FHot Inflation Pressures: High 30s to Low 40s (psi)Camber: -2.5° to -5.0°Caster: As much positive as possible Related Information: Competition Tire Heat Cycling Service | Shaving Tires for Autocross / Track Use / Competition | Recommendations on Proper Use, Handling and Storage of This Tire in Colder Climates (PDF)