Renthal front chain-wheels are simply the finest front chain-wheel on the market today. Our Front chain-wheels feature a specially developed nickel-chrome-molybdenum steel which is case hardened and core refined to give the ultimate combination of strength and hardness. Grooved chain-wheels have cut outs at the bottom of the tooth to allow the escape of mud that would otherwise be trapped between the chain-wheel and the chain. Allowing the easy escape of the mud prevents tension being placed on the chain and the resulting accelerated wear.