Maxxis Gravel Tyre - ASPEN ST - 700X55C - HYPR-X / EXO / TR - Foldable 120 TPI E50

Maxxis Aspen ST 700x55c

 Tyre Tech

The Aspen ST needs little introduction in XC racing circles nicknamed the "Fastpen" for good reason, it's the tyre that Keegan Swenson ran to back-to-back Leadville 100 victories and that Maxxis' World Cup short-track squad have relied on for years. The 700x55c edition takes that race-proven tread and reengineers it specifically for the gravel market, and the result is arguably the most technically interesting gravel tyre Maxxis has produced.

The tread

The Aspen ST's defining characteristic is its ultra-low-profile centre tread a mix of file tread and shallow chevrons that prioritises contact patch over knob height. Where a conventional gravel tyre relies on taller, more open blocks for grip, the Aspen ST bets on rubber quality and contact area. The side knobs mirror the standard Aspen,  progressive height, well-spaced, giving confident cornering traction without the rolling penalty of a more aggressive shoulder. In a 55c casing, that contact patch grows meaningfully, making the tyre well suited to the kind of high-speed hardpack and variable gravel surfaces that define events like the Life Time Grand Prix series.

The compound

This is where the 700c edition diverges from its MTB sibling. Where the 29" Aspen ST runs MaxxSpeed,  Maxxis' top-shelf XC compound the gravel version is built around HYPR-X, the brand's new gravel-specific rubber developed for the 2025 season. HYPR-X is a hybrid of two existing Maxxis compounds: the low-rolling-resistance HYPR used on Maxxis' road range, blended with MaxxSpeed from the XC mountain bike world. Maxxis claims the result delivers 25% less rolling resistance and 19% better cornering traction than their previous dual compound gravel rubber. Lab testing on the Reaver the first tyre to receive HYPR-X confirmed a 20–25% rolling resistance reduction, putting real numbers behind the marketing claim.

The casing

120 TPI throughout, now built with an upgraded stronger nylon yarn that Maxxis say improves tread durability without affecting suppleness. EXO sidewall protection is standard the cut and abrasion resistant woven material that has become a staple of Maxxis' gravel and MTB range. Tubeless ready, and at 55c, the volume is there to run pressures low enough to let the casing work properly over rough ground.

The hotpatch

The 700c edition wears Maxxis' revised gravel-specific hotpatch graphic the subtle grey/black treatment introduced across the HYPR-X gravel range distinguishing it visually from the MTB Aspen ST and signalling its gravel intent clearly. It's a small detail, but it matters on a tyre that could easily be mistaken for an XC race tyre fitted by someone who knows what they're doing.