Frequently Asked Questions
WARRANTY PROCEDURE & TIRE CARE
Challenge tires are handmade, providing incomparable performance, but are also special and delicate at the same time.
If you think your tire has a defect that would fall under a warranty replacement, please follow these steps for approval.
If your tire was purchased in a shop, bring in a photo of the problem and the tire itself back to the shop with the purchase receipt if you still have it. Explain how long you have had the tire for, the approximate number of miles that you have put on and the conditions in which you have been riding on the tire. The shop will send all information back to the Challenge distributor, who will recognize if it is an accepted warranty case or not. As soon as the distributor acknowledges it as a warranty, the shop may proceed to grant you a replacement tire, which they will in turn receive replacement for.
In rare cases, you may also be asked to look for a production run number on the product. The open tubular clincher has a manufacturing number (or date) stamped inside on the product for you to note. A tubular will have to be cut open to read this number inside. But this is only when unexplainable situations occur, that require further investigation by the factory.
If you purchased the tire from an online retailer, please forward them all the above information and photo. They should be able to process it the same way. However, if they can’t or will not handle the case, then write to us at: challengetech.it/contact
Be prepared to inform us of where you bought it from and whether they’re denying taking care of warranties. Then likewise supply a photo and all of the information explained above.
In most cases factory defect tires are replaced immediately, but it may take a few days determining whether it was a factory defect or a mishandling problem.
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 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.
Proper tire care:
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 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 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!
WHAT IS AN OPEN TUBULAR?
An open tubular is constructed using the same casing and tread materials and process as a tubular, but instead of sewing the casing together (closed), the sides of the tubular casing are folded around aramid fiber cords to produce beads. This ‘open’ design performs like a tubular, yet conveniently mounts like a standard clincher tire.
If combined with a Latex inner tube the ride becomes even closer to that of a tubular, offering excellent traction and cornering, low rolling resistance and shock absorption.
HOW DOES AN OPEN TUBULAR COMPARE TO A TRADITIONAL CLINCHER?
WHAT DOES "TPI" STAND FOR?
Threads Per Inch (TPI) measures the number of threads in a casing, which translates to how thin and supple the tire is, and its overall quality. The higher the thread count, the better the quality of the tire.
Corespun is a technical, high-performance fiber. It's made with a polyester inner core and a cotton outer layer. A Corespun casing is more supple than Poly or SuperPoly and more puncture resistant and lighter, as well.
The tubular with a softer corespun casing can be inflated to higher pressure without loosing grip and confort.
Suppleness is key for a performance tire, allowing for increased cotact of a better contact patch and lower rolling resistance.
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, which has made our Criterium Challenge famous over the years, remains unchanged.
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, greasers, ammonia, degreasers, daylight and heat. 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
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.
GENERAL 'GOOD PRACTICE' SUGGESTIONS PRIOR TO GLUING TUBULARS
Tubulars require a little attention prior to gluing and mounting.
It is important to mount and inflate the tubular to 8 bars for a minimum of 12 hours.
This process allows the tire to stretch and regain its shape before gluing (after it has hung in a shop and priorly been shipped and/or packaged).
In this phase you must make sure the tubular is centered on the rim and confirm the round shape before deflating.
Where the tubular were not aligned properly, deflate the tubular and align it, balancing the view of the slight exposure of the base tape on both sides of the rim.
Re-inflate the tire and leave for 12 hours before gluing the tubular.
This operation will help you mount the tubular more easily during final gluing and assure proper alignment and roundness of the tubular during the life of the tire.
WHICH CYCLOCROSS TIRES TO CHOOSE FOR EACH CONDITION? - SEE THE WYMAN METHOD:
CONDITION: Predominantly hard-packed ground
Dry first option: Grifo XS - Provided it was dry, I would start my pre-ride on the Grifo XS. These tires are fast and you can be confident in the corners. If you find you slide beyond what you feel comfortable with in the corners, try to lower the pressure, in very small amounts.
Wet first option: Chicane - Hard-packed ground when wet will usually only give you a problem in the corners and transition areas. I would first try the Chicane as these give you all of the confidence in the corners. You might even be able to run these at a slightly higher pressure, as you'll naturally have the grip in the corner.
Other options and scenarios: Grifo - If the course has muddy sections due to the wet (maybe you are in a late race and the course is already cut up), then go with the Grifo. This is a great option providing you with the best of both worlds above. You can be confident with a Grifo and they give you amazing variability when you alter the pressure.
REMEMBER: You don't need to run the same tread front and back. Also don't assume the same pressure front and back is the right option for you.
CONDITION: Dusty hard-packed ground
First option: Grifo - There is lots of time to be made in the approach and exit of a corner. Having the confidence to carry race pace through a corner can be the difference between winning and loosing. The Grifo provides excellent corner grip and gives you a great feeling of security when the bike isn't totally leaned over.
Second option: Fango - These are a commonly-chosen option for people that like a fast-rolling tire with a little extra corner grip. Varying your pressure between the front and back can transform the way these treads perform.
Other options and scenarios:
The Grifo XS could be great. If the dusty areas of the course are straight, or if there are slow corners that take the skill element way, you might find you can excel with the Grifo XS. These are fast tires and are more versatile than you might first expect.
REMEMBER: Always ride whats best for you. Don't be influenced by those around you. Riding with confidence in your equipment makes you fast. Approaching a corner slowly because you've risked a more aggressive tire choice could slow your lap time down.
CONDITION: Loose over hard packed ground
First option: Grifo - When the ground is loose, you need to feel at one with your bike. You need to put your focus in pre-ride to find the best lines. The Grifo gives you the ability to move around on your bike and give you the right balance between grip and speed on the straights.
Second option: Chicane - If the course is loose, but you fancy riding in a “foot out, flat out” style, try the Chicane. Maybe you'll slide a few more inches but you can be sure the side-knob grip is going to kick in and you'll be fast on the exit as soon as you hit the straight.
Other options and scenarios: Loose ground can cover many things. If the loose sections are on uphills, you need to consider a Limus rear so you can really get the power down and keep traction.
REMEMBER: Always consider the type of loose ground you are on. You might want to run slightly higher pressure to avoid a flat if there are largish stones on the course. Ride with finesse and you'll be fine. My tip would be have a slightly higher pressure on your pit bike to avoid a second issue.
CONDITION: Dry course with short sand sections
First option: Whatever you would use for the course should the sand not be there. Don't change your race for one short section of sand. Consider the remainder of the course first and put your energy into being first into the sand pit.
Second option: Grifo XS - If there are multiple sand sections, try the Grifo XS on a low pressure. This is the natural choice for loose sand, but if its going to neutralize the way you ride the remainder of the course then its potentially not worth it.
REMEMBER: You can ride sand on any of the Challenge tire options. Dry sand is loose, and best ridden on a very low-pressure Grifo XS. Ride the ruts, and look forward to the exit of the sand pit.
CONDITION: Sandy course
Dry first Option: Grifo XS - This is the natural tire choice for these conditions. Think of the Koksijde World Cup course as a pure-sand course. You are aiming to float over the sand and keep as little sand flicking all over your drivetrain from the tire treads as possible. Run them low.
Wet second option: Grifo - The Grifo might allow you to run a slightly more balanced race. If there is a little moisture in the ground, a fraction of the skill of sand riding has been taken away, and the sand will lean towards speed more than balance. Having the ability to corner fast in the wetter corners could mean faster entrance to sand sections.
Other options and scenarios: If you have sand on one side of course and not on the other, you could consider 2 set ups if there are going to be a large number of pit changes. If you can change fast you won't lose time and could have the best options for both sides of the course.
REMEMBER: When riding sand, steer with your eyes by being focused on the exits to the sand zones. You can ride sand on any of the tire options available from Challenge. Start aggressive and move up the grip options as you feel necessary.
CONDITION: Dry grass
First option: Grifo XS - There is more side grip on these than you might think at first. I tend to run slightly lower pressure in the front for my first lap of pre-ride and see how that rolls. Dry grass and fast transitions make for quick races.
Second option: Fango - The choice of many for grass is the Fango. Fast in a straight line and great on off-camber, the Fango can give a great second option for grass races. Even with higher pressure, these are option well worth trying.
Other options and scenarios: Chicane - The Chicane might give you that little more security in the corner, particularly where the grass is a little longer and you get some great bite in the large side knobs.
REMEMBER: If you are pushing things with your first option, put a more grippy option onto your 2nd bike. A fast dry course should mean no changes. A change in these conditions means potential disaster recovery, so plan for it in advance.
CONDITION: Wet grass
First option: The Grifo is going to be a great option to try first off. With wet conditions, be prepared to slip and slide and maybe keep the pressures towards your personal lower limits. This will give you maximum contact in the corners and allow you to power away in the straights.
Second Option: Limus - If you think the course could really get cut up, then consider the Limus. You'll have lots of grip and it will clear very quickly on any asphalt sections.
Other options and scenarios: If you feel the course will dry up very quickly, you could try the Chicane. You'll still have all the corner grip and it could save you a bike change.
REMEMBER: Find the limits of the tires. Don't change for a tread with more grip before you have experimented with your pressures.
CONDITION: Wet dirt
First option: Limus - It will give you a consistent performance all the way around the course. They are faster than you think and shed well enough you might be able to get away with no pit changes.
Second option: Chicane - The Chicane could come into its own if you are still able to get the power down on the straights. Lower pressure will help with somewhat slippy conditions and you have grip close to a Limus in the corners.
Other options and scenarios: Grifo - The Grifo is a very happy tire in the dirt, wet or dry. Try it if you don't quite feel you are getting what you need out of the Limus or Chicane.
REMEMBER: Try to read the conditions. If you think it's going to dry up quickly, plan in advance.
CONDITION: Sticky mud
First option: Limus - The Limus is your best friend in these conditions. All you need to focus on is finding the right pressure for you, then you can be confident you can ride where others can't.
Second option: If you don't have a Limus in your armory, then consider the Grifo, nice and low. Get that tread flat across the mud and you will be amazed at the grip.
Other options and scenarios: You might be able to get away with a Grifo on the front and Limus on the rear. If the course has multiple long straights, you might be fine with this as it allows you to get the power down and maybe keep the speed up on the asphalt.
REMEMBER: Ride the ruts. They are faster and you can see what's in them rather than hit hidden obstacles.
CONDITION: Snowy mud
First option: Chicane will come into its own in these conditions showing its versatility if the mud is light. Snow means cold, so the grip will be needed in the corners. You might have hidden frozen ruts so plan for slightly higher pressures when first checking out a course.
Second option: Limus could be your best option especially if the day is warm enough for the course to defrost mid-race.
Other options and scenarios: You might find a Limus on the rear and a Chicane on the front could be the fastest option.
REMEMBER: Frozen courses have a lot of hidden problems. Its worth an extra warm up lap to try to get the course very dialed in.
CONDITION: Snow and ice
First option: Grifo XS - This would be the first option for me in pre-ride. I want as much rubber on the floor when I hit ice. Snow itself can give lots of grip in a corner so give the Grifo XS a try before scaling up your grip.
Second option: Chicane - This will give you a little more grip in the corner, helping you flow in the technical sections. These are really good when the course has more protected areas like in woods where less snow has reached the ground.
Other options and scenarios: Fango - Fangos are good in the ice. How much of the course has exposed ice is something you need to consider. You might find the Fango is a great option for you.
REMEMBER: Riding in ice is a confidence thing. The more you can ride a course like you would in the dry, the better you are going to be. Try to adjust your tread choice, not your riding style.
First option: Grifo XS - With all icy conditions I try to ride the Grifo XS. They grip by giving me a lot of surface area on the floor, plus they keep me quick in the straights.
Second option: Fango - This is a good option on the ice. Running low pressures they give exceptional grip and seem to be very at home in the ice.
Other options and scenarios: If you suspect the course will warm up and might get more slick in the corners, start with the Chicane and certainly consider this on the front.
REMEMBER: As with other conditions, set your second bike up to try to predict for course changes and certainly give yourself a more secure option for a last-minute change before you can get your pit crew to change your option for you.
ARE HANDMADE TUBULARS AND OPEN TUBULARS MORE SUSCEPTIBLE TO CUTS THAN CHEAPER CLINCHER TIRES?
The short answer is probably yes. The longer answer is more interesting and here you will learn from the experts how to prevent a majority of these cuts from becoming a problem.
The natural latex and rubbers that handmade tires use in their casings and tread rubber are softer and stickier than synthetic rubbers and vulcanized processes used for normal clincher tires. Therefore a Challenge tire may be more likely to pick-up a small sharp stone or piece of glass in the tread and hold it there for multiple tire revolutions, allowing the stone or glass to progressively cut the tread and eventually the casing. Essentially the same special soft, sticky materials that give the casings and treads incredibly low rolling resistance, cornering and traction also make them more susceptible to cuts if certain precautions are not applied.
In January 2013, the Belgian woman’s team Challenge sponsors reported multiple cuts on many Challenge training and racing tires. They had some similar problems with other tires and with Challenge in the past but now it seemed much worse. We felt this was strange because our second, larger (meaning both more and bigger riders), men’s Belgian team was riding the same tires and were not reporting any problems. We went to the men’s team training camp in Calpe, Spain to investigate this problem (along with having other technical discussions).
Immediately when I brought up the problem in front of team management they looked at me incredulously and said, ”What? You do not know that you need to apply vinegar to the tires before riding in this “season of the little stones”?” I could not have been more stunned.
They then patiently described (like to a child) that “everyone in Belgium” knows that in the “winter” (which in Belgium is the standard three months plus two months on either side when you can get “winter” for two hours on any give day) you need to take special precautions against tire cuts.
The state trucks that sand or grit the roads plus heavy rains that wash dirt from the fields combine to dump many small, sharp stones and pieces of glass into the roads. Cars then spray the stuff to the sides of the roads where cyclists are forced to ride through it. Average people know you need thick, heavy, hard tires on your commuting bike to keep from getting flats. Riders and mechanics for professional teams are all taught at a young age that you must treat racing tires with vinegar every two to three days during “winter” (or when “winter” suddenly reappears).
“Vinegar.” I said again, patiently, “Vinegar.” I thought they are pulling some old Belgian joke, which would be fine, but I did not want to pass along the joke before I understood I alone bore the brunt of the joke. “Yes,” they said, “You must wipe the tires with vinegar, any cheap vinegar, to clean the sticky oils from the tread and “dry out” the surface of the natural rubbers.” I know that vinegar is an astringent that will dry oils from your skin so I let them continue.
“The small sharp stone or glass may still stick in the soft rubber but after using vinegar the centrifugal force of the spinning tire will be sufficient (with the less sticky tread) to throw the sharp object out of the tire. The problem only comes when the sharp object stays in the tread and continues to cut, deeper and deeper.”
Hmmm… fortunately a mechanic walked into our meeting at that moment so I told my manager friends to stay quiet and I asked the mechanic how he kept the sharp stones or glass from cutting racing tires. He said, “Well, of course, I must apply vinegar to all of the tires every day or two before riding in the “winter” season.” Normally in Spain or Italy or southern France it is not a problem but he heard from other mechanics that this year, with winter snows heavier and further south, they needed to use the same process in these areas.
OK, the mechanics and managers were all in on the joke but I needed one more check. That night at dinner I chose one of the younger Belgian riders who came from a cycling family and asked him the same questions. He said his father taught him the same story when he was 12. Vinegar.
Long story short, if you want to have all the incredible performance - low rolling resistance, cornering and traction – that the Pros enjoy with Challenge Handmade tubulars but do not want to get a bunch of cuts or punctures, simply keep a rag handy and wipe your tires with vinegar every couple rides in that “season of the small stones”.
I ONLY HAVE ONE SET OF TUBULAR WHEELS AND I LIKE TO HAVE SOME NEW, PRE-STRETCHED TUBULARS AVAILABLE. DO YOU SEE ANY PROBLEMS IN STRETCHIN 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 not to break the rim. Rims without a hub and spokes don't have much radial strength.
SHOULD I AGE HANDMADE TIRES?
Handmade tires have separate pieces of tread and casing, which are glued together. The bond of the glue improves for 6-8 months, so pro teams buy tubulars at the end of the previous season and keep them in storage to get the best longevity, and ideally you should, too.
Store them in a dry, dark, room-temperature place lightly inflated and without any folds that could weaken the casing.
WHICH DIRECTION SHOULD I MOUNT MY CYCLOCROSS TIRES?
Many cyclocross treads are directional. Note: “Forward” refers to the direction of the tread when looking at the top of the tire, and will be the same as how it touches the ground.
The Grifo can be used in different directions to achieve different results.
If you point the arrow < < < of the tread forward the tire rolls faster.
If you turn the tire around with the arrow pointing backwards > > > the tire has more grip but added rolling resistance.
The rear tire is usually more suited to switching directions. Have fun trying different orientations for different conditions.
For the Limus it is advised to have the long arm of the Y “ ̶ “ pointing forward and the open V shape of the Y pointing back “ ˂ “ on both the front and rear tire.
The tire in this direction has less drag or rolling resistance. Additionally it also sheds dirt and mud better on the road, so that maximum grip is once again obtained. Using the Limus in this direction on both tires also ensures the optimal grip.
Use the Chicane the same direction as the Limus. The open V part of the Y faces backward and the long part of the Y points forward. This makes for a faster tire with less rolling resistance and helps shed mud from the tire.
The Fango will get more bite with the slightly taller end of the scoops that run down the center facing forward and will roll faster with the shorter end in front.
WHY DO MY CX TIRES MEASURE LESS THAN 33mm?
You need to check the pressure you are using when measuring the tire diameter. Cyclocross tire diameters are designed based on an inflation pressure of 3 bar (about 45 psi). While most racers race at 1.4 to 1.6 bar, it is critical that other (maybe less experienced) racers are not disqualified by UCI officials for inflating the tire to 3 bar and having the tire then measure more than the 33mm limit.
- WARRANTY PROCEDURE & TIRE CARE