Originally Posted by
eComet
As far as I know, based on the explanation from Pit Shimizu, the 1 series is for carpet and well-prepared surface, while the 3 series is for unprepared and dustry surface.
Here is the description from Shimizu.
The F1R1 and the F3R3 compound cannot compare, as raw materials of
rubber is directly different. It is necessary to use it properly according to the course.
F3R3 : Carpet and Rough conditions.
R2: Carpet and Oil Surface
F1R1 : Most asphalt road and the special pavement road
I found R1 soft rear gets less buildups from the carpet and traction last longer than R3. So, I asked Shimizu again about the compound and below is the answer from Shimizu.
F3R3 and F1R1 : At our racing field, we recommend to use F3R3 for carpet and rough conditions. Perhaps, the basic field confiditon between japan and states are different. In addition, we heard US users use high torque/power brushless motor. As the result, tires are heat-up on the such field. To avoid heat-up, we recoomend to put thin inserts.
I think Shimizu F1R1 and F3R3 is different compound, and both work great like Sweep EXP and QTS.
EXP and QTS has different rubber compound, both work great.
FYI.