First Look: Donnelly PDX WC Tubeless Cyclocross Clincher – Cyclocross Magazine

Donnelly, known for its tires that began with the Clement name, produced the successful, versatile PDX mud tread as one of the company’s first offerings. The company has since changed names and expanded to offer bikes (see our review of the Donnelly C//C cyclocross bike), while the Donnelly PDX tubeless tubular remains one of the most common tires seen on the domestic cyclocross circuit.

Donnelly (then Clement) moved into tubeless clinchers four years ago and has been successful for the racer who picks sealant over gluing. We are beginning to see more racers, especially here in North America, using tubeless clinchers at the Elite level. And now with a plethora of high-volume gravel tires on the market, thanks to Donnelly and other brands, we have plenty of great tubeless options for bumpy, dry cyclocross races.

With the gravel market covered, Donnelly has narrowed its focus on UCI tire width-restricted racers with a new 33mm handmade tubeless PDX WC clincher. Donnelly joins Challenge in being the first brands to offer handmade tubeless clinchers this season.

Donnelly’s new handmade PDX WC tubeless cyclocross clincher. © C. Lee / Cyclocross Magazine

While Challenge focused its new offerings on gravel, Donnelly returned to its cyclocross roots and aims its light, 240 TPI tubeless clincher tire at the sharp end of the U.S. cyclocross racing population facing tire width restrictions. While a very small percentage of the U.S. retail-paying cyclocross market can’t enjoy the benefits of higher air volume, racers on frames with tire and mud clearance limitations, lighter riders or racers facing more tire width restrictions (like in the U.K.) will also find the new PDX to fit the bill, frame or tire-measuring block.

Donnelly’s new handmade 33mm PDX WC tubeless cyclocross clincher is aimed at UCI-tire-width-restricted cyclocross racers. © C. Lee / Cyclocross Magazine

The new PDX WC has a 240 TPI casing with tan sidewalls, is 80mm bead-to-bead and is made in the Czech Republic. Donnelly says the approximate weight is 350 grams. We received four samples for review that vary from 352-363 grams. Comparing list weights, the PDX WC is heavier than the Donnelly’s tube-type PDX by 36 grams and lighter than the tubeless PDX by a whopping 76 grams.

Donnelly’s new handmade PDX WC tubeless cyclocross clincher is 34g heaver than the tube-type PDX and 76g lighter than the nylon but larger tubeless PDX. © C. Lee / Cyclocross Magazine

The tire mounts tight enough to inflate with a standard floor pump and measures just about exactly 33mm wide on a 22mm internal width rim at around 30 psi. Most racers will want to race cyclocross at a lower pressure than that. Donnelly’s Brandon Dwight reports burp-free performance below 20 psi.

Donnelly’s new handmade PDX WC tubeless cyclocross clincher measures 33mm on a 22mm internally wide rim. © C. Lee / Cyclocross Magazine

It’s worth noting that the new WC version is significantly narrower than the standard vulcanized nylon tubeless PDX and MXP tires by more than 10mm measured bead-to-bead. We recently had a Donnelly MXP 33 tubeless clincher on a 24mm internal width rim, and it measured 36mm wide. Some of that is from the rim width (about 1mm), but most of that is from the over-90mm bead-to-bead measurement of the tubeless MXP/PDX casing.

Of course, you’ll gain PDX WC width with a wider rim or more air pressure—our general rule of thumb is you gain 1mm for every 3mm of internal rim width. Those with wider rims or more air pressure might still want to measure twice before lining up to contest an age-group USA Cycling Cyclocross National Championship in Tacoma if that (somewhat dated) 35mm maximum tire width rule is still in place. (The 35mm rule, first implemented in 2010 in Bend but not really checked since, was enforced in 2018 in Louisville.)

Donnelly’s new handmade PDX WC tubeless cyclocross clincher should be as versatile the standard PDX, good in mud and still fast-rolling on hardpack. © C. Lee / Cyclocross Magazine

The PDX WC should be available mid-September with a price still to be determined. An all-black version of the PDX WC will follow soon after, and a LAS WC using the same casing will be available in October 2019. The MXP WC will be released in 2020. There are currently no plans to release the BOS mud tire in a WC casing. (We’re already campaigning for a high-volume 38mm version to compete with the versatile 38mm Ritchey Megabite and aggressive 38mm Specialized Terra.)

Stay tuned for a full review. Let’s hope Mother Nature cooperates with some early-season rain.

Weight: 350g list, 357g actual (average)
Casing: 240 TPI, tan wall
Width: 33mm list, 80mm bead-to-bead (actual)
More info: (WC not listed as of 9/6/2019)