Toyo RA-1's Info From Toyo Engineers
RA-1 Care and Feeding
1) Toyo Proxes RA-1's may be "flopped". That is, the tires can be rotated on the rim so as to move the inside shoulder to the outside shoulder position. This is actually a good way to increase the life of the tire if you are experiencing excessive outside or inside shoulder wear. If you are experiencing excessive inside or outside shoulder wear, you should flip the tires on the rim at or a little before the tires are half worn to maximize tire life. There is no difference in construction of the inside sidewall vs. the outside sidewall like the old BFGoodrich Comp T/A R1 tires, so doing this is not a problem. Also, if you are running in dry conditions, the tire can be run rotating in the opposite direction. This can be handy if for example you want to rotate the left front to the right rear position during a race weekend. Even though the tread pattern is directional, this is mostly for better water drainage. If you are running in wet conditions, they should definitely be run in the proper direction of rotation.
2) The RA-1 does not really require heat cycling. The compounding is formulated to be very stable from the beginning of the tire's life to wear out. This is one of the reasons why many racers love the RA-1 for enduro's. Also, the compound is not very sensitive to the number of heat cycles you put on it. So even if you put a lot of short easy stints on them, they will not turn rock hard. So you CAN race on green tires. But if you are running at a very fast track such as Willow Springs in California, you may experience blistering if running full tread depth.
Here are some tips when running the RA-1. I have to emphasize that these are only recommendations. Setup boils down to making the car comfortable for each individual driver.
1) The optimum operating temperature for the RA-1 compound is about 200 degrees F. A general minimum operating temperature is about 160 F and a maximum of 220 F. Because tires cool off fairly quickly, you should be reading slightly lower temperatures when checking the tires in the hot pits. So, if your pyrometer is reading 200 F or higher in the pits, you're probably running too hot out on the track.
2) Target HOT pressures are the low 40's. For the 205/50R15, if you start around 34-PSI front/31-PSI rear COLD on the Miata, you should be getting up to around 43 PSI HOT. Hot pressures in the low 40's may be a lot higher than what you are used to, but (cautiously) give it a try and see how it feels to you. A lot of times people run the RA-1 too low. Hot pressures tell you how the tires are working. Adjust cold pressures to reach the optimum hot pressure.
3) As a general rule of thumb for camber setting on the Miata, max out negative camber on the front and use about 1 degree less in the rear (-3 degrees front, -2 degrees rear for example).
4) If you are running at a high speed track with high ambient temperature (again, using Willow Springs for example), you should run shaved tires in dry conditions. Having full tread depth may lead to excessive heat retention causing the tires to overheat, performance to drop off, and then eventually blister.
5) The RA-1 has slightly softer construction then some of the other competition tires out there. One comment I hear from a lot of guys is that you can push them a lot harder than you initially think. As you get used to the tire and how it feels, you may find that the limits are higher than you initially thought. Of course, please be careful when exploring those limits!
6) Just as a side note, one misconception that a lot of beginning racers have is that even tire wear reflects optimum tire setup. That's not necessarily the case. You usually make up the most time on the high speed sections of the circuit. Therefore, you should adjust your setup to optimize tire performance in those high speed areas. This often means more negative camber to optimize the tire contact patch when the suspension is heavily loaded. What you may find is that this leads to greater inside shoulder wear vs. what you are seeing on the outside shoulder since most of your heavy braking is done in a straight line.
I hope this information helps. If you feel this information is worth wile, please feel free to post it on any of the Spec. Miata bulletin boards. Let me know if you have any other questions. Thank you for trying out the RA-1. We'll be doing our best to support you guys. Good luck, and good racing!
Thomas Okihisa
Staff Engineer
Technical Service Department
Toyo Tire (U.S.A.) Corporation
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