****** Letter from the engineers in Japam *****
Joe & all,
Sorry for the delay but I have some recommendation information to pass on that I hope will assist with the Proxes R-888 performance level experienced by the race community.
*Any information we supply at this time is not applicable in all cases*
Civic air pressure in hot stage seems to exceed the proper level.
"Front-drive & light weight" vehicles prefer 32-35psi(220-240kPa).
And If the pressure at hot stage exceeds 38psi (260kPa), it should be adjusted.
I don't think the amount of front camber is necessary for "Rear-drive" vehicle (BMW).
3.5-4.0 degree seems to be too much.
My understanding is "Solo" competition is similar to "Slalom" or "Gymkhana" (in Japan).
Each competitor is running individually, and race time is approximately 1-1.5 minutes.
In case of "Gymkhana" in Japan, air pressure of R888 is as follows.
TOYOTA VITZ (SCP10) : Cold 29-32psi (200-220kPa) / Hot 32-35psi (220-240kPa)
HONDA CIVIC (EK9) : Cold 26-29psi (180-200kPa) / Hot 32-35psi (220-240kPa)
MITSUBISHI LANCER Evolution (CT9A) : Cold 26-29psi (180-200kPa) / Hot 32-38psi (220-260kPa)
Since there are so many variations regarding track preparation, vehicle-setup, and driver's skill,
I am not sure these pieces of information are useful for all racers.
"RA-1 drivers slide the car around, R-888 doesn’t seem to like this".
"The sliding style of driving can/will overheat the tire and wear quicker".
Tire Construction change
a. Generally, the R-888 has a higher spring rate than RA-1, meaning it is stiffer
b. More cornering force per camber angle vs. R-A1
c. More cornering force at smaller slip angles
d. Overall wider tire
e. These will affect car/tire setup
RA-1’s Flying Laps
a. Testing shows RA1’s tendency to produce fast lap times at the end of it’s life.
b. If racers are testing worn out RA-1s (corded) to new R-888 (shaved), they may see that the RA-1 is faster in some instances.
* Owning a pyrometer is the best way to tell how a tire is performing.
The attached technical comparison data shows the performance improvements of the R-888 compared to the RA-1 and as you will see the camber does not need to be set so high to achieve similar cornering force compared to the RA-1.
The air pressure adjustments seem to be the most crucial as Danny Kok also stated in our phone conversation.
The starting and hot air pressures are much too high and need to be adjusted to maximize performance.
I have attached many files that may help with maximizing set-up.
Let me know if this assists the racers.
Thanks and good luck!
John Carpenter
Technical Services
Toyo Tire Canada Inc.
There are about 10 documents in the .zip file which includes some engineering tests.
Great support from Toyo Tires.
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