Quick Slicks HR01 tires are designed specifically for C.B. Design 1:24 Narrow and H&R 1:24 27x12mm wheels with a center rib/spike.
For a complete list of cars/wheels this tire will fit, please refer to the Quick Slicks Fitment Summary which is updated on a regular basis.
This is the X-FIRM compound (part number: HR01XF).
Outer Diameter (O.D.): 1.06" (26.85mm)
Width (Contact Patch): .413" (10.50mm)