Full review – 1000 miles on Zipp’s new 1ZERO HITOP SW MTB XC light but trail tough wheelset

Zipp’s new 1ZERO HITOP SW XC MTB wheelset offers a great balance of very light weight responsiveness and tough but controlled ground connection. It throws in some fancy pressure checking tech too. But how does it stack up against the opposition in the already competitive and increasingly crowded ‘downcountry’ wheel category?

Design and specification

Rumor has it that the XPLR 101 gravel wheelset was intended to be Zipp’s first XC wheelset, but the radical single wall, 3D mobile ‘ankle compliant’ rim design was too soft in feel and tracking for serious speed merchants. The same design makes Zipp's 3ZeroMoto enduro wheels heavy for carbon and similarly rubbery and slow in feel when putting power through them on climbs.

That’s presumably why Zipp have gone for a totally fresh and relatively traditional box section rim, albeit with a very shallow 21.2mm profile and pronounced asymmetric cross section. The hookless sidewall tops are flared outwards and flattened into what Zipp call wings, which is an increasingly common anti-pinch-flat trick on rims. Internal width is 30mm, which seems to have become the unofficial industry standard these days. They’re covered by a lifetime warranty too, which again is increasingly common but very welcome.

The SW wheels get a lightened ‘SL’ super slim body version of the ZM2 hubs used on the 3ZeroMoto wheels. These have a 5.45-degree maximum gap before engagement from the 66-point freehub mechanism, but there’s no extra information from Zipp on the bearings, seals or axle alloy. The freehub is available in both SRAM XD and Shimano MicroSpline formats, but the wheels are 29er, Boost width only. Brake rotor mounts are Centerlock and my test wheels had the optional Torque Cap oversized ends for better connection with RockShox forks.

Holding each wheel together are 24 bladed spokes (presumably Sapim CX-Ray as that’s Zipp go-to option) in an easy to source but potentially harder to replace, J bend format. Tension was tight and even from new and stayed that way right through several tough months of testing.

The SW wheels also come with TyreWiz valves which measure tire pressure to within plus/minus two percent and transmit it to the SRAM AXS app via Bluetooth / ANT+ connectivity. You can use this to set the sweet spot pressure range for each tire, and if the pressure goes above or below that, the blinking LED light on the valve changes from green to red.

Performance

I always start assessing wheels from the first stage of tire fitting, and the good news is that unlike some broad top sidewall designs the Zipp’s are a breeze to switch rubber on and off. I didn’t even struggle particularly when I added a CushCore XC liner for a particularly rocky, charity ‘Everest ride’ I lent them to a test team member for. Although anyone with two thousand dollars to spend on wheels is likely to have an accurate track pump, TireWiz acts as a useful second confirmation that you’re in your preset sweet spot. Going back to the CushCore though, I did get occasional deflation blockage on one wheel, even though the inner end of the valve is slotted for side ‘breathing’. Airflow isn’t as fast as the latest designs such as Reserve Filmore or 76 Projects so you might want to remove the valve core to pop stubborn tires into place.

At 1,400g with XD freehub and TireWiz and tubeless tape installed, the 1ZERO HITOP SW are over 100g heavier than the similar width and wallet emptying Roval Control SL or Bontrager’s Kovee RSL wheels. However, they’re over 100g lighter than the $900 HUNT Proven Race XC and $1,599 Reserve XC28 wheels and 200g lighter than the FFWD Outlaw XC I tested recently. Prompt freehub connection flatters the low weight too, making the Zipps very rewarding to hustle out of turns or kick hard to inflict pain on following riders or clear technical crux moves. 

Otherwise, feel is really balanced between peppy enough to feel accurate and encouraging but not so taut they ping and slice off every angled impact or slanted root. The Torque Caps keep front wheel targeting consistently accurate despite the very thin hub spindle and low spoke count too. They really shine in rough cornering situations where repeated jolts can push a wheel outwards, but they consistently kept turning in and holding course with comfortable control. While they’re not overly soft, at other times the HITOP rims really impressed me by sucking up a couple of serious slams and a rocky riverbed I went into way too fast that could have cracked a carbon enduro rim without surprising me. 

Apart from those core strengths, back-to-back riding slides them into the same category as the Reserve XC28, HUNT Proven and Bontrager Kovee RSL wheels. Not as stiff and sharp as the Roval Control SL or FFWD Outlaw, but not as magic carpet ductile as Zipp’s previous single wall rimmed MTB and gravel wheels. Their character works well across a wide range of bikes from short travel aggressive angle trail bikes to super lightweight 100mm travel FS race bikes and hardtails . They’ve worked well with Maxxis Forekaster 2.4in, Ikon 2.35in, Rekon Race and Severe 2.25in tires depending on conditions too.

Even after several savage months of testing, there’s been no creaking, loss of tension or wobbling. Despite regular rim ding impacts on EXO carcass Maxxis tires there’s been no pinch punctures and only one slight burp of a few psi when hard cornering on an off-camber, while running 17psi in an Ikon rear tire just to see how low it could go. That wasn’t immediately noticeable during the night laps of a brutally tough cancer charity Everesting challenge either, so it was good to have the TireWiz blinking red to let us know a quick pump was needed to get things back in the sweet spot. As you’d hope, bearings are still fine even after a dirty summer and the freehub is still spinning smoothly. It is relatively vocal though, so if you’re after a stealthy wheel look elsewhere.

Verdict

In terms of balanced performance, Zipp’s new 1ZERO HITOP SW are an excellent addition to an already busy category of wheels that spans XC to fast trail use. They’re not the lightest or stiffest option, but they’re significantly more responsive than a full blown trail wheel when climbing or accelerating. They trade very little (if anything) in terms of consistent control and strength through staccato root/rock or even serious block and drop trail sections. The hubs are based on existing units and the rims and build are proving perfectly durable so far with no sign of needing to call on the lifetime warranty. Even the ‘novelty’ TireWiz valves are a lot more useful than expected particularly in race/epic situations where you might otherwise not pick up pressure drop. They only add ten grams and $30 per wheel too, so they’re not a significant performance or price gouge either.

Like most lightweight wheels you are paying a premium to dip under the 1,500g mark where you’ll find a lot of very similar riding wheels for a lot less money, including Zipp’s own $1,350 / £1,400 / €1,600 1ZERO HITOP S which uses the same rim just with cheaper hubs and spokes. 

Tech specs: Zipp 1ZERO HITOP SW wheelset

• Price: $1,950 / £2,000 / €2,250 
• Sizes: 29er Boost only
• Options: Torque Cap front hub adaptors, XD or Microspline freehub 
• Weight: 630g front, 770g rear, 1,400g pair