A sibling to SRAM, wheel and component brand Zipp has revealed a handful of gravel-racing-focused products to match the new Red AXS XPLR groupset today.
Most notable of these new XPLR-branded components are the 303 XPLR SW and 303 XPLR S aero-focussed gravel wheelsets, each offering an enormous 32 mm internal rim width with a 40 mm external dimension. Such mind-bogglingly wide and hookless (TSS) rims come with obvious tyre fitment limitations, and so Zipp has expanded on its partnership with Goodyear to provide suitable “Fitment Series” tyres.
Additionally and just as we recently saw with the release of SRAM Red AXS on the road and its matching Zipp SL80 Race handlebar, the company has produced an equivalent handlebar match for gravel.
I’ve been riding the more affordable of the two new 303 XPLR wheelsets, along with the wider tyre option, and the new handlebar. Within you’ll find full details of the new products and my test findings.
Good stuff: Aero makes sense for fast gravel, impressive cross-wind stability, ultra-efficient on champagne-type gravel, easy-enough tyre install and inflation, decent weights considering the oversized dimensions, and competitive pricing.
Bad stuff: Increased compatibility limitations in an already confused market, limited approved tyre options, ride becomes sensitive to tyre pressure, thin rim sidewalls are exposed to knocks, wide rim squares the tyre profile, clearance is a concern on some bikes, squared tyre profile can do weird things to handling, exposed tyre sidewalls more susceptible to punctures.
What in the width?
No that wasn’t a typo. Zipp’s new gravel race wheels do in fact have a 32 mm internal width. That’s wider than the current status quo in mountain biking (30 mm), and it’s wide enough that the company’s pre-existing Zipp 303 Firecrest wheels (25 mm internal) slot within the rim bed of these new hoops. According to Zipp, the brand landed on that relatively extreme width for two reasons: one being aero, and the other being vibration reduction.
As average speeds in gravel races continue to increase, of course, so does interest in aero optimisation. We’ve seen the likes of 3T, Hunt, Parcour, DT Swiss, and Lightbicycle all claiming to provide a recipe for going faster with gravel-width tyres. Zipp’s efforts are arguably the most extreme example we’ve seen to date, with a significantly wider internal width than the aero options before it. Zipp combines that with a 40 mm external width, and a 54 mm rim depth (56 mm as measured) shared across both front and rear wheels.
When matched with a 40-45 mm tyre, the wide rim aims to remove much of the usual light-bulb-like shape from running a wide tyre with a narrower rim. Instead, there’s a relatively uniform and airfoil-like profile that aims to keep the air better attached and flowing more smoothly. Of course, Zipp claims its multiple trips to the wind tunnel show that it’s faster, saving approximately 5W (at 45km/ph) compared to a competitor’s gravel race wheel, but names are not named, and so I say meh to that. Still, it’s useful to know that Zipp state the wheel is fastest when paired with a tyre in the 40-45 mm range, while the brand still claims it to offer some aero advantage with even wider tyres.
According to Zipp, far greater speed gains can be had in reducing rolling resistance and vibrational losses. While certainly not alone, the American brand’s testing has shown that lower pressures are always faster on rough surfaces until the point it negatively impacts bike handling. However, merely dropping pressures on existing rim widths tends to quickly introduce tyre sidewall instability and increases the risk of pinch flats. A wider and/or higher volume tyre is the answer to dropping pressures, and it’s why we’ve seen a trend amongst elite gravel racers to pick the widest tyre their gravel bikes allow.
From Zipp’s point of view, having such a wide rim means more air volume and that the tyre sidewalls are more directly supported, which in turn allows pressures to be safely reduced to well below 30 psi. Zipp’s rim design also borrows from many mountain bike rims, where a wide (4 mm) and blunt rim edge reduces the risk of pinch flats in the event the tyre bottoms out. You can bet I’ll come back to this topic.
There are two price point options to the new 303 XPLR range each with the same rim dimensions, 24 spokes on each wheel, and the company’s generous warranty program that covers in-ride damage. The flagship 303 XPLR SW (US$2,1000 / €1,800 / AU$3,150) offers a higher-end carbon lay-up, features Zipp’s signature texturing on the exterior of the rim, and has Zipp’s six-pawl ZR1 hub (with increased sealing) laced with Sapim CX-Ray bladed spokes. Zipp offers compatible freehubs to suit all major drivetrain options, including Microspline for Shimano GRX 1x12-speed and N3W for Campagnolo Ekar. All told, these wheels carry a claimed weight of 1,496 g, including rim tape and tubeless valves.
Then there’s the more affordable 303 XPLR S that I’ve been testing. Priced at US$1,400 / €1,200 / AU$2,150, these wheels feature a more basic carbon fibre layup without the fancy textured details on the exterior. Laced in place with cheaper/thicker/heavier Sapim CX-Sprint bladed spokes, the hubs are Zipp’s simpler three-pawl 76/176 DB models, with just SRAM XDR and Shimano HG freehubs are available to suit. Zipp claims a pair of these to weigh 1,642 g, with my test pair coming in at 1,623 g (XDR freehub, including tubeless rim tape and valves).
Tyre compatibility
Going 32 mm wide on a hookless rim designed for 40 mm+ tyres breaks new ground and, therefore, introduces a long list of caveats and compatibility limitations. If you thought the saga of hookless compatibility was beginning to iron itself out, then sorry to say, the mess has been unZipped and spread all over the floor.
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