21mm inner rim width; variable 45mm to 40mm rim depth; White Industries hub; tubeless
Exceptionally stable in crosswinds; better price than most of its competitors; awesome hubs
38mm max recommended tire size; would love to see these officially able to handle 40 or 42mm tires
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Princeton CarbonWorks has had a bit of an uphill battle to ensure riders understand there’s a major difference between its sinusoidal rim shape and the biomimicry shape that Zipp touts on its 454 NSW wheels. Aesthetically, the two designs look similar, but according to Princeton, they work vastly differently. Such is the case with the Grit 4540 wheels, which feature that characteristic sinusoidal shape in a wide-rim package suitable for on-road and gravel use.
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It’s all sinusoidal
When I reviewed Princeton’s Wake 6560 D wheels, which feature the same sinusoidal pattern as the Grit 4540 wheels, I was of course wondering how the rim’s shape differed from that of the Zipp 454 NSW wheels in a practical sense: Did the unique pattern offer any distinct advantages over Zipp’s pattern? And do these unique humps offer any advantage over other rims that don’t have such shaping?
It’s hard to tell whether the sinusoidal shape of the Grit 4540 wheels differs drastically out on the road from the Zipp 454 NSW’s sawtooth shape, but I can tell you that both sets of wheels (all three, really, when you include the Wake 6560 D wheels) do seem to perform better in crosswinds and other winds at yaw than wheels without such shaping.
So in that sense, I was excited to get my hands on the Grit 4540 wheels because I knew from my experience with both the Zipps and the other Princeton wheels that these wheels would likely feel planted and stable in windy conditions. And I was not at all disappointed: The Grit 4540 wheels are perhaps the best road wheels I’ve tested in crosswinds.
It certainly seems like there’s something to this rim shape, and Princeton is ready and willing to back that up with its own wind tunnel testing and CFD data. Since I did not get these independently tested, however, I can neither confirm nor deny Princeton’s data.
Aside from aerodynamics and crosswind performance, Princeton says the sinusoidal pattern allows them to craft a lighter rim that’s stronger too, since the tops of the waves can be reinforced for mating with the spoke, while other parts of the rim can use less material to reduce weight since reinforcement isn’t needed there.
Beyond the humps
The Wake 6560 D wheels were excellent for road use. The Grit 4540 wheels are too, but they also go well beyond the pavement, making them a versatile wheelset for the multi-surface rider.
The 21mm inner rim width goes 3mm beyond the Wake 6560 wheels, which means you can run larger tires and take full advantage of the tire’s shape and ride characteristics. Princeton says the Grit 4540 wheels can handle up to a 38mm max tire width (though the company has tested up to 42mm).
Princeton also removed all the holes from the tire bed. That allowed the company to make said tire bed thinner, thereby eliminating some weight. On top of that, the lack of holes increases stiffness and makes the overall rim stronger. All this according to Princeton, of course. In practice, what that mostly meant for me was that I didn’t need to tape the rim. That’s one less step when setting up the wheels tubeless.
My test wheelset came with White Industries hubs, which were wonderful complements to the overall system. The freehub engagement feels quick and positive, and while the tell tale buzz is loud enough to hear, it’s not annoyingly grating as some freehubs have become in the last few years.
Riding the Grit 4540 wheels
So far I’ve only tested the Grit 4540 wheels with road tires on them (Specialized S-Works Turbo RapidAir 700 x 28c tires, to be specific). I’ve ridden both on pavement and gravel with this setup.
I can certainly imagine myself riding a wider tire with these wheels if I was doing a lot of multi-surface riding; if I had to do it all over again, I’d probably throw some 30mm tires on there. That said, I’d also feel plenty comfortable taking off the road tires entirely and throwing on some gravel rubber to make this my go-to gravel wheelset, especially if I had some races on the calendar. While Princeton says the max tire you should use with these wheels is 38mm, I wouldn’t hesitate to put on some 40mm tires and go full gravel nerd.
Like the Wake 6560 D wheels I tested, the Grit 4540 wheels feel exceptionally stable in crosswinds and winds at yaw. I could end the review there and tell you these wheels are worth the investment just for that; fortunately, I can also go on and tell you the wheels feel responsive and stiff under big power efforts like sprints and steep climbs, too.
Pair that with a very respectable weight of 1,530g/set and the Grit 4540 wheels seem to validate their worth, especially given they’re almost half the price of some of the competition. While prices are indeed falling in the carbon wheel market, Princeton is already there, offering an excellent combination of aerodynamics, light weight, and solid ride feel.
Out on the road, I couldn’t really find fault with these wheels. The only thing I wonder about is Princeton’s aerodynamic claims, but frankly, that’s something I wonder about every company’s claims. It’s just impossible to tell without independent testing.
These wheels are a solid buy. While they certainly aren’t cheap, they come in less expensive than many competitors, and offer a ride quality that parallels, if not exceeds, many of those same competitors — especially when the wind is blowing. In direct crosswinds the Grit 4540 wheels are among the best I’ve tested, and they are just as stable and predictable at various yaw angles. With a wide stance that takes full advantage of modern tires, and allows you to dabble in multi-surface riding or straight-up gravel, these wheels are versatile too.