Challenge 'HANDMADE' production
All tubulars and open tubulars produced by Challenge are special, high-end, handmade products. Handmade production is a process minimizing the use of heat treatments and especially avoiding a very high heat treatment called vulcanization. In order to obtain a good quality standard, the manual skill required in each step is very high.
Our ‘Handmade’ production allows materials to maintain their original suppleness and flexibility achieving the best grip and producing an ultimate performance product. A supple Challenge tire is able to absorb and reduce harmful vibrations passing from the road to the body that are produced by riding harder vulcanized tires on stiff carbon bikes ultimately causing muscle stiffness, inflammation and fatigue.
Our very top casings are made of Silk or top quality cotton weave called Corespun, the next level down being SuperPoly. Corespun weave allows us to obtain both supple and strong, but lighter casings at the same time. These very top level casings can reach a TPI (thread per inch) count of over 320TPI. At the next SuperPoly level the TPI count can easily reach over 300TPI achieving also very strong and in fact less delicate casings than the higher cotton level.
The casings, which are sewn round with an inner tube inside, are mounted on rims and then inflated and the treads are then slowly hand glued on them. The tread is laid on the inflated casing enabling it not to suffer any tension, instead of being placed on casings which are subsequently inflated. The treads made of all natural (non-petroleum based) rubber, combined (via Handmade production) with the quality, high TPI count casings result in tires with lower rolling resistance and increased comfort offering a safer and more precise handling of the bike. The tyre absorbs irregularities of the surface with its subtle give and slight deformation, increasing road surface contact and guaranteeing both shock absorption and great grip while cornering.
Additionally, a special fabric (PPS-Puncture Protection System) is placed between the tread and the casing in order to increase puncture resistance. The casing is then sewn around an inner tube (that’s why they were originally called ‘sew-ups’) and now takes the form of a ‘tubular’ tyre with inner tube. Base tape is applied over the sewing and then this tubular tyre is glued onto a special tubular rim.
Challenge SILK – best of the best.
In addition to polyester and cotton, Challenge is one of only a couple manufacturers producing Silk tubulars and tires. Silk is unfortunately very expensive and only few countries supply a good enough grade of silk to make a high-performance tubulars. Silk, like cotton, is a natural(not man-made) fibre. Where as cotton has the advantage of being less expensive, it unfortunately tends to absorb moisture and water, and may end up rotting in time, if not properly cared for, whereas silk does not absorb water, is even finer and can be woven at a much higher count (which is almost impossible to count).
This means that silk casings are even more supple and much stronger than cotton (also against side cuts), overall longer lasting, more puncture resistant and providing even lower rolling resistance; all for an even more demanding rider
wanting to ride comfortably at high speed. It is not a surprise that silk is mostly used on the track. Silk is also offered as a road and cyclocross tyre. If it weren’t for its price, it would also really be offered as the ultimate Paris-Roubaix tyre due to its extreme suppleness and yet very cut-resistant casing.
These tyres are for racing style bikes that use clincher/hooked rims, these are the most common fitment and hook onto the rim and require an inner tube. There is a wide choice of tyres within this category and the right choice is important. Lighter tyres will accelerate quickly, but will be more prone to punctures so getting a balance is extremely important. If you require a tyre for all round use look for something with puncture protection, an average TPI(Threads Per Inch) and average weight. If you require a fast tyre and speed is the only thing that matters look for a low weight folding tyre with high TPI. If durability is your priority and speed is not so important look towards the puncture resistant tyres and consider going for a wider tyre, these will be less prone to punctures and offer a bit more comfort. For wet road conditions a triple compound or winter tyre is a good choice, these use a softer compound on the cornering surface to maximise grip.