GX20 Gekkota. GX20 Gekkota Arrives. GX20 Gekkota will be IRC's brand new tire based on their medium-compound GX20, which was developed with first ever Japanese ISDE Gold Medalist Tadashi Kugimura in 2019. Sharing rubber compound with JX8 Gekkota, it provides maximum grip when things get slippery, while maintaining the traction on the loose stuff with an FIM compliant tread pattern. The GX20 GEKKOTA comes only in a 140/80-18 size and is the lightest of ISC's 140/80 Gekkota tires at 12.7 pounds. 2P+B structure provides both stability and shock absorption performance at high speeds. Optimization of block spacing ensures dirt removal performance. Splitting the center blocks into several sections improves stability when braking. Traction is improved by making the blocks larger on the edges. Tire Specifications: Type: TT. L.I.: 70M. Overall diameter (mm): 696.