Ample tire clearance is one of the defining features of most modern gravel bikes. More tire clearance expands a bike’s versatility and allows riders to take on rigorous adventure riding of all kinds. The extra clearance is also useful for muddy rides and races, helping prevent mud from collecting between the frame and the wheels, which would typically render the bike unrideable. Without altering a bike’s geometry too much, many gravel bikes are designed around increased tire clearance.
One useful feature of gravel bikes with big tire clearance is the opportunity to use both 700c and 650B wheels with the same frame. Each of these wheel sizes offers different benefits and ride experiences suited for various adventures. 700c wheels feature a larger diameter rim and are the standard choice for most gravel riding and racing. 650B wheels have smaller diameter rims that are often paired with bigger volume tires for added compliance and traction.
Deciding which size is right for you depends on your local terrain, personal riding style, or the specific adventures you’re preparing for. Shimano GRX gravel wheels are available in both 700c and 650B sizes, delivering reliable performance for diverse riding conditions.
700c Gravel Wheels
With a larger overall circumference, 700c wheels often roll faster on hardpack and non-technical surfaces due to lower rolling resistance. These wheels have a longer, narrower contact patch between the tire and the ground, which allows the wheels to maintain momentum better and maintain speed longer. The bigger circumference also enables 700c wheels to roll over obstacles or holes in the road more fluidly
700c wheels are the ideal choice for gravel riders focused on speed and efficiency. The larger rims paired with tires that typically range from around 35mm to 42mm tires offer enough cushion and comfort over rocky gravel roads without sacrificing speed and momentum. It's the choice wheel size for Shimano's top gravel racers, and the 700c GRX wheels offer versatility for tackling all kinds of riding conditions.
650B Gravel Wheels
The smaller diameter 650B wheels allow riders to use notably wider tires than 700c wheels, and these high-volume tires can be run at lower pressures. Fat and plush 650B tires offer better traction on loose, dirt climbs or descents, and they soak up the lumps and bumps better over technical terrain. Additionally, when using the same frame and gearing, you'll feel like you have an extra climbing gear with 650B wheels compared to 700c, due to the smaller circumference.
Gravel riders who'd rather play around on the local mountain bike trails rather than hit the open roads will appreciate 650B wheels. The smaller diameter rims and big tires deliver a more playful feel when zipping around singletrack, and they soak up the bumps and roots for a smoother ride. 650B wheels are also a good choice for touring and bikepacking rigs. Bigger volume tires ranging from 40mm to 2.1 inches offer more compliance for loaded bikes, and the smaller gear ratios resulting from a smaller wheel diameter offers an easier climbing gear for loaded bikes.
Gravel riding is diverse and opens the door to new roads and drop-bar experiences. Whether you're a gravel racer looking for the fastest, most dynamic setup or you're taking on a multi-day gravel bikepacking trip, Shimano GRX wheels deliver confidence, speed, and reliability for any adventure ahead.