Bridgestone Battlax S21 190/50ZR17 73W TL Rear Motorcycle Tyre. The focus is almost always the same when a new tyre is developed. More mileage and better grip and nothing is any different with this beauty from Bridgestone. The new Bridgestone S21 Battlax is the new hypersport motorcycle tyre as the “S” in the name suggests. The manufacturers claim that these tyres are a different level to its predecessor, the Battlax S20. The S21’s promise much better dry grip and performance but at the same time, combines the technological development of the improved S20 EVO when it comes to wet grip. The superior stability gives the rider sharper lines and faster exists on the road or track. Another strong claim is the 36% more mileage compared to the S20 which is great all round and value for money.