Princeton CarbonWorks and Ineos debut new Peak 4550 ultralight wheels

The so-called "Meilenstein Killer" is sub-1,100 g, but with a modern aero shape.

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Remember the speculative article we published a couple weeks ago on the Princeton CarbonWorks Peak 4550 wheels that Ineos star Tom Pidcock was testing? Well, we weren’t right about everything, but we were right about most of it. Ineos Grenadiers is indeed planning to run Princeton CarbonWorks’ new Peak 4550 carbon wheels for climbing stages at this year’s Tour de France, but in tubular form, not tubeless clincher. 

The folks at Princeton CarbonWorks have dubbed the Peak 4550 the “Meilenstein Killer” — a not-so-subtle dig at the Lightweight wheels that Ineos Grenadiers riders have been using in mountain stages. In its lightest form with tubular compatibility and rim brakes, Princeton CarbonWorks says the Peak 4550 weighs just 1,071 g per set. That’s 141 g heavier than the Lightweight Meilenstein Obermayer, but 94 g lighter than the standard Meilenstein, while also presumably offering much improved aerodynamics given the far more modern rim shape.

Straight-line efficiency is likely better with the more U-shaped Princeton CarbonWorks wheels as compared to the Lightweight’s old-school V-profile, but based on my experience with the Wake 6560 model, the real advantage will likely come in high-speed stability and crosswind handling.

The Peak 4550 features the same undulating rim depth as found in Princeton Carbonworks’s other two wheel models, only this one is more focused on low weight.

Princeton CarbonWorks doesn’t appear to have gone to any extreme lengths to reduce weight. The wheels are built with conventional Sapim CX-Ray bladed stainless steel spokes (just 16 up front and 24 out back) instead of the Lightweight’s carbon fiber ones, and the hubs are off-the-shelf models, too. The tubular rims even utilize a solid outer rim wall, which not only improves rim strength, but also provides extra surface area for a more secure bond with the tire.

Princeton CarbonWorks didn’t go into great detail on the brake tracks on the rim-brake models, but suggested they incorporate all the latest features to ensure they not only provide good bite, but can survive high heat.

“We used [Ineos Grenadiers’] feedback to tweak and develop this brake track for confident descending and predictable stopping on big mountains,” said Princeton CarbonWorks founder and CEO Harrison Macris. “Obviously, there are all the buzzwords of ‘high Tg’ and brake track lab data, but we also rely on empirical testing and feedback from the riders. For what it’s worth, during lab testing, the tire blew out well before the brake track experienced any fade or degradation.”

Solid outer rim walls provide more bond area for the tubulars, and an inherently airtight cavity for the tubeless clinchers.

Princeton CarbonWorks is offering the new Peak 4550 wheels for both rim brakes and disc brakes, and in both tubeless clincher and tubular versions. Rim-brake clincher models are said to weigh 1,297 g, while the disc-brake version is 1,348 g. Internal width on the clincher models is 18.5 mm, and external width on all rims is 26 mm. In other words, these are very much intended to be used for road riding and racing with relatively narrow (25 mm or so) tires.

“Disc-brake rims are lighter than their rim-brake counterparts because we don’t need to build up the brake track as much,” Macris said.

Although buyers will eventually be able to get the Peak 4550 wheels in any of those four configurations — with their choice of White Industries or Tune hubs — the company is kicking things off with a special Launch Edition model built around ultralight Carbon-Ti hubs and emblazoned with bolder graphics. Launch Edition wheels will be offered until July 31, at which point those will be discontinued and replaced with the standard versions.

Launch Edition wheelsets get rather loud graphics.

Retail price for the Launch Edition wheels is US$3,400; standard Peak 4550 wheels will be US$3,100. Pricing for other regions is still to be determined.

“We did a lot of development to make this a Grand Tour-winning wheelset and have big ambitions for it,” Macris said. “Internally, we (PCW and the team we developed it with) called it the Meilenstein Killer, because we wanted [it] to be lighter, stiffer, and more aero. We checked all the boxes and the rider feedback has been very positive.”

Sounds like it’s time to review another set of Princeton CarbonWorks wheels, eh?

More information can be found at

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