Zipp 1ZERO HITOP SW Disc Brake Centerlock 29" Wheel SID Blue Graphic - Rear

The Zipp 1ZERO HITOP SW Disc Brake Centerlock 29" Wheel SID Blue Graphic - Rear is Zipp's first cross-country-specific wheelset in nearly 30 years, and the gap shows in how differently the company approached it compared to a typical XC wheel. The rim uses Zipp's proprietary HiTop carbon layup in a hookless, asymmetrical, winged profile — 21.2mm deep, 30mm internal width, 37.7mm maximum external width — built in UD carbon. The winged shape gives the tire a smoother resting surface against the rim, which reduces the odds of a pinch flat when you clip a rock or root at speed rather than just adding material to make the rim stiffer everywhere.

That distinction is the whole point of the HiTop design. Zipp's engineering team, led by design engineer Aaron Packard and test engineer Brian Leathers, built this wheel on the idea that maximum stiffness isn't actually what makes an XC wheel fast anymore — as Zipp puts it, a wheelset should feel alive rather than just being stiff above all else. The rim is engineered to comply with rough terrain instead of transmitting every hit straight into the rider, while still holding the stiffness needed for efficient climbing and hard accelerations out of corners. The project carried over momentum from Zipp's 3ZERO MOTO enduro wheelset, adapting that same terrain-compliant approach to the lighter, faster demands of cross-country racing.

At the hub, this rear wheel runs Zipp's ZM2 SL hubset with 66 points of engagement, available with an XD or Microspline driver body to match SRAM or Shimano drivetrains. In its lightest configuration, the 1ZERO HITOP SW comes in at roughly 1,375 grams, and it integrates with Zipp's TyreWiz 2.0 system for real-time tire pressure monitoring — useful on a wheel built around running tubeless tires at precise, often lower pressures than riders default to. It's rated for tubeless tires in the 47-71c range, roughly 1.85 to 2.8 inches, with a 50 psi maximum pressure and a 286-pound system weight limit, and Zipp built it to handle bikes with up to 130mm of suspension travel — squarely in cross-country and light trail territory rather than anything built for aggressive descending.

The SID Blue graphic on this wheel isn't an arbitrary color choice. It matches the Blue Crush signature colorway RockShox uses on its SID Ultimate fork, and since Zipp and RockShox are both part of SRAM's component family, the pairing lets a rider building a dedicated XC race bike match their wheels to their fork rather than mixing graphics from unrelated brands. It's a small detail, but it reflects how tightly SRAM coordinates its component lines when a rider is building a bike around one ecosystem.

What all of this adds up to on the trail is a wheel built for riders who need speed to survive contact with actual terrain, not just a number on a stiffness chart. Cross-country racing has moved toward rougher, more technical courses over the past several years, and a wheel that flexes intelligently over roots and rock gardens while still transferring power efficiently on the climbs is a direct response to that shift. For a racer building a dedicated XC bike, or a rider who wants a lightweight 29er wheel that can carry speed through rough sections rather than getting knocked off line by them, the 1ZERO HITOP SW is Zipp applying its carbon engineering experience to a category it hadn't touched in decades — and building something purpose-specific rather than a road wheel philosophy adapted to dirt.