Panaracer's Fastest Gravel Tire Yet—But Only If Your Routes Are Smooth Enough

Panaracer just released the GravelKing ZX, a semi-slick tire they're calling their fastest option for mixed terrain. It's aimed squarely at riders who spend time on pavement, hardpack, and loose gravel in the same ride—which describes most gravel racing and a lot of weekend exploring. The pitch: road-tire speed on smooth surfaces, predictable cornering when things get loose.

The tread uses a three-zone design. The center is slick for low rolling resistance. An inner transition zone with small arrow-shaped knobs engages when you brake or lean. The outer edge has two rows of progressively taller shoulder knobs for grip in loose corners. What's different here is that the center slick sits about 2mm proud, matching the height of the shoulder knobs, so the profile curves smoothly across the tread. That matters because many semi-slicks feel abrupt when you transition from center to edge—this one reportedly doesn't.

The ZX uses Panaracer's ZSG Gravel compound (same as the X1), a single-compound formulation instead of dual-compound. Single compounds are simpler to manufacture and tend to wear more predictably, but they don't let you optimize center speed and edge grip independently. The casing gets TuffTex puncture protection and BeadLock bead tech for tubeless stability at low pressure. It's available in 700c only, from 35mm to 55mm. Right now, only 45mm and 50mm are shipping; other sizes roll out through 2026. The standard ZX costs $65. Claimed weight is 560g for 45mm, 640g for 50mm. Actual scale weight on a 50mm sample: 625–628g, so about 12–15g under claim.

Here's the catch: semi-slicks are a compromise. You're trading some loose-surface traction for pavement speed. If you're riding chunky, wet gravel or mud, a full knobby will outperform this. The ZX makes sense if your routes are variable—long stretches of pavement or hardpack with occasional loose sections—but it's not the tool for technical singletrack or sustained soft conditions. I haven't put miles on it yet, but the spec that matters is that raised center profile and whether the transition zone actually smooths out the on/off feeling most semi-slicks have. Early ride reports suggest it does, but that'll depend on your rim width, pressure, and lean angle.

If you're a data-driven rider trying to squeeze speed out of mixed routes without swapping tires, the ZX is worth watching. It's not revolutionary—it's iterative refinement on a known design. Panaracer went through six mold iterations to get the tread profile right, which suggests they were chasing a specific feel rather than just copying what's already out there. Whether that translates to noticeable performance for a busy dad with limited ride time depends on how much of your route is actually smooth enough to benefit from a slick center. If it's more than half, probably yes. If it's less, you're carrying dead weight.