Could 750d wheels replace 700c? Moots and WTB share the details about their custom gravel bike

(Photo: Alvin Holbrook/VELO) Photo: Alvin Holbrook/VELO

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Tucked away in the heat of SBT GRVL 2023 was a new Moots gravel bike dubbed the Moots Routt CRDD. It isn’t too different than the new Routt CRD they revealed recently. But this one is different: it is built with a new 750d wheel size, a departure from the 700c wheels found on just about every other gravel bike not only at Moots, but at SBT GRVL.

The Moots Routt CRDD custom gravel bike with 750d wheels was easily one of the most asked-about bikes at the MADE Bike Show. We pulled it aside to check it out and see if the claims about larger wheels are true.

What is the 750d wheel size? Why does it exist? Will it replace 700c wheels? Here’s what we found out.

This new 750d wheel size consists of a wheel and tire combination that is larger than the 700c wheels we see on most road bikes and gravel bikes (not to mention a 29er wheel size). It isn’t quite as big as something like a 36er wheel size, but 750d wheels with a 40mm tire comes to about the same outer tire diameter as a 29-inch wheel with a 2.4-inch tire.

700c wheels (and 29er wheels as well) are made to an external rim diameter of 622mm. These prototype 750d rims measure 660mm.

In comparison, some gravel bikes and road bikes come with a slightly smaller wheel size than 700c called 650b. Those rims measure in at 584mm. This makes 750d a reasonable jump in size.

The purported benefit of the 750d wheel size is to provide better rollover over rougher terrain (like gravel!) with a slightly larger contact patch. It aims to offer these improvements while still being easy to ride and still being more maneuverable than the aforementioned 36er wheel size.

We’ve heard benefits like these before with other wheel size jumps, namely in the mountain bike world as they went from 26-inch wheels to the far more common 29-inch wheels and tires we see today. Momentum and stability tend to improve, and the improved rollover ability means a bike with these wheels will feel more stable when the going gets rough.

Additionally, some have intuitively sought out these benefits by going with as big of a tire as they can on their bikes. Not only does a wider tire make for a larger contact patch, but it also effectively extends the outer diameter of the tire just a bit.

Jon Cariveau at Moots mentioned the specific need they’ve seen to make bikes that are proportional to the rider. Shorter riders aren’t always the best fit for 700c wheels. At the same time, taller riders might find value in the potential added stability and performance that comes from an effectively bigger wheel size.

To note, 750d wasn’t specifically made for larger riders. The Moots Routt CRDD found here has fit geometry centered around a rider who would otherwise be on a 54cm frame. That is one of the most common frame sizes, meaning there is the potential for 750d wheels and tires being for the meat of the market.

Will we see more bikes with 750d? Moots is hesitant to say. But they pointed out that the WTB Nano tire used here was also the first-ever 29er tire we saw. Not only that, but Moots was one of the first manufacturers WTB worked with in testing the new wheel size. It’s fun to see the two companies come together again to ruffle some feathers.

While most folks are likely tired to hear about yet more “innovation we don’t need,” a new wheel size makes sense immediately for taller riders. Furthermore, just about everyone can benefit from the added stability that comes from a larger wheel with improved rollover. I suspect this isn’t the last time we will hear about 750d, though I wouldn’t rush to replace your gravel bike or road bike quite yet.

See more MADE Bike Show coverage here.