I Kit DID Professional The rider, buying the DID Professional chain, is aware that he has chosen the best quality product available on the market, traditionally from which he demands reliability, durability and economy of operation. However, it is always advisable to replace the pinion and crown included in the kit even when the profiles of the teeth visibly seem regular. Kinematics, regular winding, chain-profile tooth roller coupling, must be in perfect harmony, to optimize le performance of the transmission. Otherwise the gear damages the chain, le regular joints, accelerate the process of degradation of the crown itself. Normally within the Kits they si japan Sunstar gears and le chains are in many cases, pi? quality class above the same DID in the first equipment. and? precisely for this reason that professional DID , represent a safe, reliable, long-lasting reference recommended by the best experts in the sector. This prestigious product? intended for pi? demanding, accustomed to long journeys and that does not disdain even a sporty use of the bike. Pinion: 15 teeth Crown: 47 teeth Chain DID 525 118 Meshes