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Gravel Tires Tubeless

Donnelly XPlor MSO WC Tubeless Gravel Tire

The Donnelly X'Plor MSO tire design is a shout out to the Adventure Cycling Association, headquartered in Missoula, Montana. Hence the airport code, MSO, for the tire designation. Developed with the needs and requirements of adventure cycling, the X'Plor MSO Tubeless Tire is a large volume, highly versatile option for adventure, all-road/gravel, commuting, and specific cyclocross riding. Even better, the MSO WC is produced in Europe with the finest materials and the utmost attention to detail. It is made with the highest quality, Japanese produced nylon casing available, features 240 TPI construction and weighs just 460 grams. A great adventure/gravel tire just got better.

The fast rolling design has surprising hook-up in mixed surface riding, and the 40mm size is ideal for this type of terrain. The development of the tubeless version no doubt had MSO riders cheering, as the the ability to take advantage of high and low pressures without pinch flats, as well limiting puncture flats through sealant use makes the X'Plor a perfect tire for most riders. The tread pattern is the first reason the MSO jumps out at you. While it looks fast rolling and somewhat solid in the center, a closer look reveals directional vector knob clusters and shapes that do roll fast and pretty smoothly on pavement, but have slight separations and incuts that ensure grip on hard, slick surfaces, such as dusty or wet rocks. Just off the center on both sides are a one-one series of small and larger hexagonal knobs that pitched front to rear. These knobs carry your grip and consistent feel off the center when cornering, offering stability on pavement and grip off-pavement. The top of the shoulder/edge features a combination of the same larger hexagon of the inner line, but is offset with a small triangular knob, that points to the centerline. Again, here is your cornering transition, but with slightly more open space, also a source of traction in softer terrain, especially at lower pressures.

The pure edge tread line is a story in itself. There is a tandem knobset, with a flat edge, five sided, smaller forward tread paired with a larger, mirrored version of the same shape, but which has a beveled top surface that is higher in the rear. Between the mirrored pair, in sequence, are two smaller hexagonal knobs with more space in between. This design is for enhanced grip, stability, and traction, especially in off-road or trail riding situations where softer, or loose material can get sketchy, and despite the fact that this tire says "fast rolling" the hook-up is excellent and confidence inducing. A brilliant tread design all around.

Donnelly has developed a proprietary tubeless ready construction and it is clear that the walls have been reinforced with rubber, yet there is suppleness delivered by the Japanese produced nylon casing material at 240 tpi. The bead is a strong, proven design of heat resistant Aramid fibers so you can run this tire with tubes or tubeless. The surface and tread rubber is a softer but durable, offering grip good wear, lower rolling resistance, and overall durability. Rubber grip and the tread combine to make the function of the tread pattern and tire footprint greater, so the tire pressure you choose will be driven by conditions and terrain.

The listed weight for the MSO WC 40mm tire is 460 grams, with the 700x36 about 15 grams lighter, with Donnelly's proviso that weights are +/- 8%. This may sound off, but if you have ever weighed tires, you know how much variation there can be. You want to run an ammonia-free sealant, such as Stan's NoTubes. The tire mounts reasonably and seals exceptionally well. The durability of the sidewall and under tread protection is impressive. The recommended pressure range is 40-60psi, though several independent reviews suggest excellent viability down around 30psi, which would be dependent on rider weight, conditions and use. We suggest before setting out on an adventure or trail ride, work through a few pressure tests on a controlled route so you can evaluate what works best for you. We are impressed with the X'Plor MSO WC Tubeless and we suspect you will be as well.


  • Tubeless ready adventure tire designed for the most ambitious rides and events
  • WC = Premium construction in Europe to exacting specifications, material upgrade
  • Japanese produced nylon casing available, features 240 tpi construction
  • Versatile, fast rolling tire with impressive grip, traction and handling capability
  • Tubeless casing is reinforced for wear, fully sealed, features an Aramid bead
  • Protection through sidewalls and under the tread
  • Soft rubber compound for extra grip and shock absorption
  • Smooth-rolling center with siping to provide increase traction without a lost to rolling resistance
  • Intermediate knobs/aggressive shoulder lugs to provide confidence in corners, on loose surfaces
  • Can be run tubeless or with tube
  • PSI range: 40-60 psi
  • Recommend current sealants like Stan's NoTubes, that are ammonia-free
  • Sizes: 700x36, 700x40
  • Colors: Black, Black w/Tan sidewall
  • Size/Weight: 700x36 / 445g | 700x40 / 460g (+/- 8%)