Frequently Asked Questions
WARRANTY potential issue & tire care
Challenge tires are handmade, providing incomparable performance, but also opening the door for infrequent human error.
Challenge is one of few factories in the world mastering this artisan manufacturing process. Because we consider maintaining the rubber’s natural properties of primary importance, we avoid extreme prolonged heat treatments.
The majority of other tires are industrially produced using this heat treatment, called vulcanization, which helps bond the materials together. The consequence is that it dries and hardens the rubber, reducing the rubber’s grip, its shock-absorption properties and ultimate ride quality, all of which are of particular importance for a performance tire.
Making handmade tires is a difficult process and we pay constant attention to each step and detail. Nevertheless, rare situations may occur that are imperceptible during production and that pass by the QC (quality control) inspection.
The tread is applied manually and — as with any manual operation — slight, involuntary human error may occur. These are rare cases that occur less than 1% of the time and we are constantly striving to bring that number closer to zero.
The most common case is when the side of the tread isn't properly adhered to the casing. This is not a manufacturing problem but a rare case of human error when handling the product.
If a worker touches the side of the tread improperly when applying it to the casing, his fingers may have taken off a spot of glue, causing adhesive problems. In this event, the glue appears well adhered in the QC check, but the problem becomes more perceptible during use.
Another possibility is that the tread may come in contact with a chemical agent, such as solvent, when cleaning the base tape and applying the glue to the cotton tape. The solvent is also used afterwards to clean the tread area after gluing it to the casing.
Problems may also occur when a user mishandles a perfect product. These are high-end, handmade products which require proper care.
High-pressure bike washes damage delicate tubulars. When possible, avoid washing tires with high pressure, and never point the stream directly at one spot of the casing. Also avoid scrubbing sidewalls with stiff brushes.
Cleaning agents that contain degreasers also damage tubulars. Remove tubular wheels before using harsh cleaning products on your frame.
In most cases factory defect tires are warranted and replaced immediately, but we do ask for a few photos and description of each problem, as it is quite easy for us to determine whether it was a factory defect or a mishandling problem.
In order to avoid mishandling or misunderstandings, please communicate the handmade process and proper care to staff, dealers and teams to get the most out of your performance tires.
What does TPI stand for?
The TPI (Thread Per Inch) is the number of Threads in each Inch of lenght of the casing. The TPI is traditionally used as a parameter to determine the quality of a tubular and of a tire in general. To a higher number of Threads correspond a better quality tire.
The Corespun is a technical fiber, very soft and resistant. It's made with a poliester inner soul and a second cotton fiber that surrounds sit. A corespun casing is much more puncture resistant due to the increased resistance of the fiber and to the thikness of its structure. Softness and flexibility are also improved.
The tubular with a softer corespun casing can be inflated with slightly higher pressure without loosing grip and confort.
"Softness" is a key issue on high performance tires. As a matter of fact, the deformation of the tire and the constant contact patch allows increased grip and confort. Rigid tires tend to loose contact with the ground, loosing grip as a consequence.
Despite the increased number of threads, Criterium 320 tubular is about 10 grams lighter than the previous 300 TPI version.
The TPI is important but it's not the only one feature when we look at the quality of a tire. The Compound used for the tread is important as well. A new Carbon High Tech compound has been developed to perfectly fit the new corespun casing and give the best of the performance. With this new super soft compound the tubular has a perfect grip doesn't matter if you are riding on wet or dry ground, and a very low rolling resistance is granted at the same time.
The traditional tread design, that has made our Criterium Challenge famous over the years, remains unchanged.
What is “handmade”?
The main feature of "handmade" tubulars is that no vulcanisation treatment is done, except for the one done separately to the tread before it is applied to the finished casing.
First the single ply is made on the loom, using only the warp held together by a latex coating which replaces the conventional weft.
Subsequently two single plies are attached together in a round shape and the threads of each ply are placed to form a herringbone pattern.
This new coupled ply is then pressed with hot cylinders, cut to the desired size and the edges folded for subsequent sewing.
The finished casing is obtained by sewing the two edges of the ply together, inserting the inner tube at the same time.
The ribbon is manually applied to cover the stitching, and to serve in the future to glue the tubular to the rim.
The finished casing is mounted on a rim and then inflated. The tread, separately prepared, is manually applied and the tubular is now ready!
I only have one set of tubular wheels and I like to have some new, pre-stretched tubulars available. Do you see any problem in stretching new tubular tires on some old clincher rims that I have lying around?
Go for it. Just be careful putting them on the rims! We would recommend using a rim strip. That will protect your tubular base tape from the rough edges of the spoke nipple holes in the rim bed.
If you're using bare rims and not a complete wheel, also be careful when stretching the tubular in that you don't break the rim. Rims without a hub and spokes don't have much radial strength.
I bought GRIFOs for my bike. How should I mount them?? Do the arrows of the profile have to be < < < ...in the drive direction or go the opposite direction: > > > ??
The GRIFO is a very special tread pattern which can be used in both directions!
If you point the arrow < < < of the tread forward the tire is faster having low rolling resistance.
If you turn the tire around with the arrow pointing backwards > > > the tire has much more grip. In this case it is not as fast because there is an increase in rolling resistance.
It really depends on the type of course you have. So you can actually find your perfect setup according to the course and your style if riding.
The front tire in most cases is kept with the arrow forward, but in a few occasions can also perform better the other way..
The rear tire is usually more suitable to switch directions.
Have fun trying !
How can I prepare my tubulars for off-season storage?
Here are a few tips to help you summer-ize your cyclocross tubulars.WASH
Wash your wheelset using water with dish soap or diluted Simple Green. Avoid harsh scrubbing of the delicate sidewalls with a stiff-bristled brush. Instead, use a sponge or softer brush. Stiff bristles are OK for the treads.
Thoroughly dry the wheels by hand with a clean towel and let air dry completely. Tip the wheel on its side and tilt slightly one way then the other to let any water trapped in the rim drain.
Inspect the tread of the tires for cuts, glass, little bits of stone, and abrasion. Check if any lugs are loose or missing. Small cuts can be repaired and filled with Super Glue. Check out the valve cores. Are they bent, loose, dirty? Unscrew and dry them before tightening.
Look at the sidewalls. If your tires have cotton casings (Dugast, Challenge and others) they should be sealed to protect them from and moisture. An unprotected cotton sidewall will rot if wet and dry out if stored unsealed. If they are already sealed, inspect the sealant for peeling or bubbles. Dark or black spots indicate moisture and rot. If you need to re-seal, I recommend removing the old before applying a new coat of Aquaseal. Make sure the sidewalls are completely dry before sealing, otherwise you are just sealing in the moisture. If you do re-seal, wait until the sealant is dry before proceeding to the next step.
Inflate the tires to 30-40 psi and check the glue job by trying to roll the tire off the rim. Don't check just one spot, go all the way around the rim. If you have to re-glue, I suggest waiting until late summer or whenever you are a few weeks out from your first race.
Store the wheels either in wheelbags or on your bike. In either case hang them - bike on a hook or wheel bags from a hook. Leave some air in the tires and check them every month or so. This will help the sidewall hold its shape and avoid pinching or folding. Latex tubes will lose some air over time. Lastly, whether the wheels are in bags or on your bike, put them in a temperature controlled, dry environment out of direct sunlight like a basement (or garage if you live somewhere where it does not drop below 45°).
Follow these steps and your tubulars will be ready to go when September comes.
Why is SILK used? Benefits?
Silk is unfortunately expensive.
BUT it is natural and has many “Top-Class” properties:
- Much finer but stronger weave than cotton or polyester
- Impossible to count TPI as threads are so much thinner/finer than cotton or poly and count is extremely higher!
- At the same time softer and more supple even to cotton or poly
- A maximum level of comfort reached with a very strong holding product !
- A demanding and technical rider will also feel it rides smoother and faster.
An 8-Bar inflated Tubular is quite comfortable, while a Silk Tubular with the same pressure seems almost not inflated enough.
The feel is slightly different with Silk. In fact on the Track where they want higher inflating pressures and the fastest performance, this is where they will often prefer Silk.
Use of Latex inner tubes: pros & cons?
Latex inner tubes are more supple than normal butyl tubes. They adapt quickly to the tire changing shape while cornering and rolling. This is because latex extends and expands 7-8 times its original size, butyl only about 1.5, which means latex is much more flexible, guaranteeing more speed, improved rolling resistance and comfort than a standard butyl tube.
Latex inner tubes also weigh less than standard butyl tubes so can help save weight.
They also increase puncture protection; the latex stretches and deforms around the body which is trying to penetrate the tube instead of it trying to resist the body and shortly after being punctured through. The highly elastic latex material is very difficult to puncture.
The big disadvantage of latex lies in poor air retention. Latex is more porous and gas permeable. A tire with a latex tube should be checked for inflation pressure before every ride.
Installation of a latex tube is also not so easy for the inexperienced hand. It can be much more prone to pinch flats if not installed properly. The suppleness of latex means it can find its way into the smallest of cracks and holes and push itself in between and pinch.
On the other hand, if seated correctly in its cone, it can be extremely strong, reliable and a great added benefit.
Finally, latex tubes are known to be somewhat delicate. They are susceptible to oil, daylight, heat and uneven expansion. It is advisable to change the tube every time a tire is changed.
This explains why latex tubes are not often suggested for quick everyday rides.
But if you take the additional precautions and care, you’ll feel the difference and enjoy!
CHALLENGE: SEAMLESS LATEX INNER TUBE
- superior Latex formula
- unique Seamless technology
- stronger, more reliable
- smooth, no minimal pumps, not “out of round”& unbalanced
- improved rolling resistance
- best resistance to puncture
- super light weight
- two-piece removable valve core for valve extender use
- WARRANTY potential issue & tire care