To complement SRAM’s new Red XPLR AXS components, Zipp has launched a new gravel-specific wheel line – the 303 XPLR.
The brand has also collaborated with Goodyear on new gravel tyres optimised for the wheels.
The new 303 XPLR design sees a hookless 54mm-deep rim, 40mm external width and broad 32mm internal width.
The wheels are optimised for 40mm-wide tyres, but Zipp claims they out-perform the next best wheelset across tyre sizes from 38-50mm.
Zipp’s category manager and engineer David Morse tells us the new top-tier 303 XPLR SW wheelset is Zipp’s “fastest gravel wheel ever, thanks to its mega-wide and deep rim that integrates seamlessly with gravel tyres”.
Zipp 303 XPLR details
Alongside SRAM's unveiling of new Red XPLR AXS, Zipp has launched two versions of the new 303 XPLR wheels – the premium 303 XPLR SW model and a lower-cost 303 XPLR S (similar to the road-going 303 Firecrest and 303S wheelsets).
The rims are progressive for a gravel wheelset – far wider than the average widths seen – but Zipp claims these dimensions came from evaluating what the ideal gravel tyre is and complementing that to achieve optimal aerodynamic performance and “ride dynamics”.
While both wheelsets have the same dimensions, the 303 XPLR SW features Zipp’s distinctive dimpled finish to the rim.
This is said to make the airflow turbulent at an earlier point as it flows across the surface – this more energetic flow stays attached to the surface for longer, thereby improving aero performance.
The build is completed with Sapim CX-Ray spokes, built onto Zipp’s six-pawl ZR1 hubset with heightened sealing and 66-point engagement for a quick 5.45-degree engagement angle.
The 303 XPLR S uses a smooth dimple-less rim, matched to Zipp's 76/176 hubset.
The 76/176 is Zipp’s entry-level hub, and is claimed to have durable bearings and seals. The pawl-based freehub has 36 points of engagement for a 10-degree engagement angle.
Both wheelsets come with a maximum tyre pressure rating of 50psi / 3.45 BAR, Zipp’s lifetime warranty and a weight limit (rider and bike) of 130kg / 286lb.
The 303 XPLR SW is said to weigh 1,496g, while the 303 XPLR S is claimed to weigh in at 1,610g (both with an XDR freehub body).
Zipp 303 XPLR prices
- 303 XPLR SW front wheel: £750 / $1,000 / €850
- 303 XPLR SW rear wheel: £850 / $1,100 / €950
- 303 XPLR S front wheel: £500 / $650 / €550
- 303 XPLR S rear wheel: £600 / $750 / €650
The wheels ship with either a SRAM XDR or Shimano freehub, tubeless tape and valves, 12mm end caps and disc rotor lockrings.
Campagnolo N3W and Microspline freehubs are available separately from $108 (UK/EU prices are TBC).
How did we get so wide?
As part of the research into the new wheels, Zipp says its engineering team evaluated the current state of gravel wheels and tyres. It identified four issues.
1: Wheel aerodynamics are ruined by mismatched rim and tyre widths
Zipp found typical tyre widths for gravel racing range from 38 to 50mm across all tread patterns, while the current “market leading” gravel wheel designs have an external rim width of 28 to 30mm.
Zipp says this creates a mismatch between the rim shape and tyre, which is exacerbated when you get to 40mm-plus sized gravel tyres, which are becoming ever more popular in gravel racing.
Zipp’s deep dive into the history of one of the biggest gravel events globally – Unbound – found that as the race has progressed over the years, speeds have increased. In 2006, they averaged around 25kph and by 2024 that figure had risen to more than 30kph.
From this information, the brand identified aerodynamic gains are becoming ever-more important, alongside comfort and control.
The brand says the rim’s 54mm depth, along with the increased width, creates the optimal shape with a 40mm tyre.
According to Zipp’s testing, the pairing of the new 303 XPLR rim shape and the new Goodyear co-developed 40mm tyre provides a 5-watt aerodynamic advantage over a leading competitor.
2: Tyre pressures for gravel terrain compromise bike control on narrow rims
Zipp’s research shows that lower (optimal) tyre pressures significantly increase speed on gravel.
It says the problem with current gravel wheelsets is the narrower tyre bed causes the tyre to collapse when cornering, negatively impacting grip and control.
The 303 XPLR’s wide tyre bed is said to increase the tyre’s stability, which in turn results in reduced tyre squirm under cornering loads.
It claims the other benefits are decreased vibration losses (because the tyre complies to the surface, as opposed to bouncing across it), more predictable handling and unbroken traction when climbing.
3: Current rim designs compromise tyre reliability
Zipp says that when gravel riders choose higher-volume tyres, but mount them on rims that are narrower than optimal, it increases the chances of pinch punctures and tearing if the tyre collapses under load on rougher surfaces.
The 303 XPLR rim design is said to help reduce the chance of pinch flats thanks to the “correct” shaping of the tyre, plus the rim edge, which is 77 per cent thicker than a 303 Firecrest.
In the worst-case scenario, the widened edge is claimed to spread the impact loads better if you manage to compress the tyre enough to hit the rim on the ground.
4: Vibration robs riders of speed
With current rim and tyre combinations, Zipp says it found riders needed to run the tyre pressures higher than should be considered optimal.
In turn, the increased vibrations not only compromise control, but increase fatigue because the rider needs to put in more effort to maintain race speeds.
Zipp’s research into this included evaluating Zipp riders at Paris Roubaix, where it found its sponsored team’s riders put in more than twice the number of watts through the tough Arenberg Forest sector than on the concrete velodrome in Roubaix at the race's finale.
It claims that when simply maintaining speed on gravel surfaces, you can be trying to overcome up to 100 watts just in vibration loss.
Tyre compatibility
The rim design complies to ISO 622x32 TSS standard.
Zipp recommends the use of tyre sizes of between 40 and 60mm – 18mm less than the ETRTO’s lower recommended limit, and 24mm lower than the organisation’s upper limit (58-84mm).
It’s worth noting that Zipp is part of the working industry group that assesses these standards.
When asked, Zipp said it tests tyres on its rims “separately”, using its in-house protocols, to 150 per cent tyre pressure in excess of the wheel-tyre system’s stated lower limit.
It then asks tyre brands to run their own tests according to their protocols.
If both are in agreement, they are declared safe by Zipp and the tyre brand, and published on Zipp’s online compatibility list.
At the time of writing, the list consists of the Goodyear XPLR series (more on this to follow), Zipp G40 and all Schwalbe G-One models (40mm and wider).
The brand says more tyres from other brands are set to be approved over time.
New Goodyear XPLR tyres
Just as Zipp announced new road-going tyres in partnership with Goodyear recently, it has now launched a fresh tyre collaboration for the 303 XPLR.
The new Goodyear XPLR comes in two flavours – the dry-weather XPLR Slick and the versatile, mixed-conditions XPLR Inter.
The Inter is available in a 700x45c size and is designed to inflate to 45mm wide on the 303 XPLR rim.
It comes with a close tread pattern at the centre to provide low rolling resistance. The bigger and more widely spaced outside blocks are there to help cut through less optimal surface conditions and provide grip through corners.
The sidewalls use Goodyear’s M:Wall construction, which it claims helps provide puncture protection against cuts and pinch flats, enabling the rider to get away with the lowest possible air pressure.
The tyre is still claimed to be supple and compliant, with an M:Wall protected casing, and lightweight at 525g.
The 700x40c XPLR Slick is designed to measure up at exactly 40mm wide, mounted on the 303 XPLR rim, and has a fully slick centre section for the fastest rolling speed on smoother surfaces and dry conditions.
Tread texture and cornering blocks are claimed to ensure a high level of confidence in corners.
Like the Inter, it’s claimed to have a light, supple carcass enhanced by M:Wall reinforcements.
Both models use Goodyear’s Dynamic:UHP compound, which is claimed to help improve grip and lower rolling resistance. Both also feature the Goodyear/Zipp-designed ‘Dual Angle’ bead, which is said to provide secure retention on the hookless XPLR rims.
Zipp and Goodyear state the Goodyear XPLR tyres should only be used when mounted to 303 XPLR wheelsets.
Goodyear XPLR specs and prices
Goodyear XPLR Inter
- Price: £80 / $80 / €90
- Size: 700x45c
- Tyre type: Tubeless
- Bead type: Folding, Dual Angle beads for XPLR rims
- Compound: Goodyear Dynamic:UHP
- Weight: 525g (claimed)
Goodyear XPLR Slick
- Price: £80 / $80 / €90
- Size: 700x40c
- Tyre type: Tubeless
- Bead type: Folding, Dual Angle beads for XPLR rims
- Compound: Goodyear Dynamic:UHP
- Weight: 455g (claimed)
