The challenge limus 33 tubular cyclocross tyre has deeper 33mm knobs for increased traction in deep mud speed and maximum traction all in one all tubular and open tubular produced by challenge are special hand made products machines are not able to produce them and the manual skill required in each step to obtain a good quality standard is very high the casing is produced with the latest technical materials like corespun a cotton and polyester combination corespun is a thread from which w