The 21" front tire grips with measurements 140-160 and an inner diameter of 31mm are components located on the front of the motorcycle and are used to provide increased comfort and control to the rider. These grips are designed for 21" front wheels and tires with measurements 140-160mm. The inner diameter of 31mm refers to the measurement of the grip's fit with the handlebar. They are made with durable and resistant materials such as rubber, to provide a secure and comfortable grip at all times.Referencia: HR9004