Challenge limus open cyclocross tyredeeper 33mm knobs for increased traction in deep mud'. '.strtoupper('s')peed and max'. '.strtoupper('t')raction all in one.open tubular differ from traditional clinchers for the construction'. '.strtoupper('t')he tyre is produced just like a tubular and uses the same materials and production process'. '.strtoupper('i')nstead of being sewed with an inner tube inside, at the end of the process beads are made by folding the casing around aramid fibers threads'. '.strtoupper('f')or this reason an open tubular gives very similar ride feel of that of a tubular, mainly if a latex inner tube is used.mounting an open tubular on a wheel is the same as mounting a standard clincher but with the advantage of riding a much more comfortable and performing tyre'. '.strtoupper('b')uilt for the intensity of riding in extreme conditions, this tyre is a perfect upgrade for maximising your control during muddy conditions.features use cross racing all around, sticky mud size 700 tyre width 33mm internal rim width 15 19mm tpi 300 bead aramid casing superpoly flat protection pps bar 2 6 psi 30 90 weight 370gtechnologies challenge handmade clinchers hcl these handmade clinchers are made from the same materials and processes as our handmade tubulars but instead of sewing an inner tube inside the casing is wrapped around an aramid bead to form a tyre that fits on a clincher rim'. '.strtoupper('t')he hcl is moulded flat, not in a horseshoe like a tlr or vcl'. '.strtoupper('t')his shape allows the casing to naturally deform over surface imperfections and minimize rolling resistance'. '.strtoupper('a') tubeless tire is moulded in a u shape to make the sidewalls rigid, so the system does not “burp” or lose air when it deforms after it encounters a surface imperfection'. '.strtoupper('t')he tubeless tire's stiff sidewall compromises its ability to equal a supple hcl with a latex inner tube.buy challenge wheels tyres from chain reaction cycles, the world's largest online bike store.