No other component than tires has so much impact on your performance on race day. There is a reason that pros arrive to key races with multiple wheelsets loaded with different tire treads - tiny differences in tire performance can make huge differences in race outcomes, and at high levels races are absolutely won and lost based on tire choices.
Tubular tires (also called "sew-ups") are glued or taped onto the rim. At the professional level almost all riders will use this setup. Highly desirable because they allow very low tire pressures to be used.
pros of tubulars: Best "feel", well established as the standard for high-end cyclocross bikes, traditional choice, handles low PSI well, impossible to burp.
cons of tubulars: expensive, can't change tread to suit the day, hardest setup, somewhat scarce and harder to source locally, proper gluing and time-consuming setup is needed or tire can come off the wheel.
Tubeless tires use a special bead and compatible rim with special valve to remain airtight without an inner tube (often by adding a sealant). The newest option as mountain bike technology influences cyclocross equipment choices.
pros of tubeless: Resistance to pinch flats, since there isn't an inner tube, relatively easy to unmount and remount different tires to suit the day's conditions, limited, but growing, selection of brands and tread types, potential for great puncture resistance, thorn or glass flats can be very rare when a good sealant is used.
cons of tubeless: Results can range from excellent to poor depending on the tires and rims selected, might need a compressor to mount and seat tires (ruling out race day changes), usually needs sealant which adds weight.
Clincher tires have a separate inner tube inside that holds air and lock onto a rim with a hook bead to hold the tire. Popular among casual cyclists but much rarer at the elite professional level.
pros of clinchers: inexpensive, easy to change tires to suit the day's conditions, easy puncture repair, simplest to setup and maintain, wide variety of brands and tread choices available.
cons of clinchers: pinch flats are a possibility, which prevents riders from using as low of pressure as they would like, worst "feel".
Note that tubular tires are the #1 upgrade recommended by RideCX - before a lighter handlebar or seatpost, faster shifting derailleur, or better brakes. Once you try tubulars you won't want to go back. That being said, tubulars have some significant downsides, so how do you choose?
Tubulars remain the highest performance option and if cost were no object and everyone had a pro mechanic to maintain their equipment, everyone would want them! Performance is certainly not the only factor when selecting a wheel/tire system however.
Tubulars could be right for you if:
- You also race road bikes in addition to cyclocross. You'll get more value out of high-end wheels if they can do double duty in the cyclocross "off-season"
- You're willing to invest the time and energy in setting them up
- You have multiple sets of wheels, including at least one backup. If emergency sealant doesn't fix your tubular puncture, you can't easily repair make repairs on-site, so a backup is needed.
- You can afford to replace the tire if you wreck it.
- Someone else sets up and maintains your gear. Let's face it, having someone else hand you a ready-to-ride tubular is the best if you have that luxury.
You might want to try tubeless if:
- You aren't ready for tubulars, but suffer from pinch flats with traditional clincher tube-type tires due to your weight or riding style.
- You come from a background with high tubeless adoption (i.e. mountain bikes) which can shorten the learning curve.
- You've got tubeless ready mountain bike wheels from a 29" MTB that can easily swap over to your 'cross bike
- Your typical race courses have thorns, glass, etc. that would puncture other tire types.
- You're a lightweight, careful rider. Bigger riders and those who corner aggressively can "burp" tires at low pressures, losing some or all of the air. As a result, higher pressures are needed to prevent burping, negating some of the "feel" benefits.
- You're willing to experiment with tire and rim combos to identify those that work well for your style. Some don't so you must be prepared if you select tubeless.
Traditional clincher (inner tube type) tires are probably best if:
- You're a casual cyclist
- You're just getting started in cyclocross
- You have limited funds to invest in equipment and/or limited time to invest in maintaining your bike
- This is an early season, tune-up, or practice race and you don't want to chance damaging your race-day equipment yet.