Tubeless cyclocross clincher tyres continue to be an enticing option for many up-and-coming racers, promising lower running pressures than tube-type setups, with fewer flats. It certainly hasn't been a painless progression but Vittoria's Cross XG Pro comes another step closer to figuring out the magic formula.
The first thing we noticed when installing the Cross XG Pro was its thick TNT (Tube No Tube) casing – typically the death knell for 'cross tyres where suppleness is usually synonymous with grip. As we expected, the tyre's rigidity wasn't great for finding ultimate traction in tricky situations, where a more compliant tyre would otherwise better conform to the ground underneath.
However, when mounted to a proper tubeless-compatible rim that stiffer casing coupled with a true UST, airtight bead allowed for lower operating pressures than with most other converted tubeless 'cross setups we've used – as low as 23psi up front for a 70kg (154lb) test rider. This partially offset the casing stiffness in most situations, allowing the tread to spread out over a bigger area, and gaining back much of the traction we thought we'd be missing.
The tread design is a variant of the original, age-old Grifo pattern, but with stouter cornering knobs in place of the flex-prone dots of the original. The medium-height and medium-spaced center blocks make for a relatively fast roll and minimal squirm on pavement and hardpack, plus good drive and braking traction.
Pentagonal transition knobs and elongated shoulder blocks on the Cross XG Pro
The Cross XG Pro starts to fall short through the turns, though. While the long shoulder knobs provide a more secure 'shelf' to lean on than the original pattern's tiny dots, they're not quite tall enough to really dig into the ground. Vittoria further hamstrings the effort with what feels like a very hard rubber compound.
Therefore, the Cross XG Pro can't corner quite as hard or securely as similar tyres with softer rubber or more aggressive side knobs, especially if the ground is at all damp. Not surprisingly, the tyre also struggles in deep mud, where the knobs just aren't tall or aggressive enough to find traction. Nor is the stiff casing able to shape itself to what's available underneath for purchase.
However, the very rounded casing profile yields reasonably forgiving and predictable drift characteristics in most conditions when it does let go. So it's more likely to let you down easily over dinner instead of suddenly breaking your heart (or collarbone, in this case) with a Post-it note.
Riders who race regularly on rockier courses will also come to appreciate the thicker casing's admirable robustness. Rather than add a thick butyl rubber liner, Vittoria instead reinforces the Cross XG Pro with an additional ply, giving it a 150TPI casing instead of the 120TPI used on the company's other cyclocross clinchers.
This means users will have to run sealant, but as a side benefit we never suffered any punctures or flats during testing, despite the abundant goathead thorns and rocks in our local area and several bottoms-out of the rear tyre.
Even the ride quality was surprisingly reasonable, albeit not as creamy as most ultra-supple open tubulars. Much like tubeless road clinchers, the Cross XG Pro's stouter construction yields a muted and well-damped feel that helps cushion the blow of rougher courses and also seems to help keep the contact patch from constantly bouncing off the ground.
The Cross XG Pro's actual weight of 388g apiece makes it a bit heavier than other high-end 'cross clinchers. But it's a reasonable price to pay for the reliable tubeless compatibility.
Overall, the Cross Evo XG Pro still can't match a tubular for all-out performance. But for amateur racers who are dying to ditch inner tubes it's a good all-round choice.