Which wheel is better for a gravel bike, 700C or 650B?

Comparing advantages and disadvantages of 700C and 650B

Advantages and disadvantages of 700C wheels

The advantage of 700C (internal diameter 622 mm) wheels is the high straight-line performance that results from the larger circumference. The larger the tire circumference, the farther a bicycle can travel in a single revolution, so the larger the wheel size, the higher the straight-line performance.

Another big advantage is that 700C is the standard size for road bikes, so there is a wide choice of wheels: for 700C, there are many choices, from aluminum to carbon, from wide rims to narrow rims, and from expensive ultra-lightweight wheels.

Having a lot of choices means more availability, which makes it easier to choose the wheels you prefer.

On the other hand, when considering 700C wheels from the perspective of a gravel bike, the limitation of tire size becomes a problem.

With 700C wheels, the clearance to the frame is narrower than with 650B wheels due to the larger inner diameter of the wheel, so the frame clearance limit is often around 700x48C size.

If you want to ride MTB-like with 50C or other larger tires, 700C is not the best choice.

Advantages and Disadvantages of 650B Holes

The advantage of 650B (internal diameter 584 mm) wheels is the ability to increase air volume by increasing the tire size. Increasing air volume allows for lower air pressure (more air volume means that the tire does not contact the rim over bumps even at low pressure), which increases drivability on rough roads.

Another advantage of low-pressure operation is that it provides more cushioning, which improves riding comfort (reduces vibration and impact on bumps).

On the other hand, the biggest disadvantage of 650B wheels is the extremely limited choice. There are not many manufacturers offering 650B wheels for gravel roads or for road use, and the narrower the choice, the lower the availability and the narrower the options.

As an image, the choice of 650B wheels is probably about 1/10th of that of 700C wheels.

Note that 650B is the same wheel size as MTB’s 27.5-inch wheels, but in the case of MTB, wheels are often mounted on 15mm through-axles, which cannot be used on gravel bikes that use 12mm through-axles.

Preparing and using two different types of wheels makes for a versatile bike

So which is better, 700C or 650B? In the end, the best answer for a gravel bike is to prepare and use both.

If you install 700C wheels for “paved road main” such as daily use or riding on bike paths, and change the tire size according to the route you ride that day, you can use 700C alone for various routes.

On the other hand, on days when you want to ride mainly on gravel, you can enjoy gravel to the fullest by using a 650B with 50C or other large tires to enhance the performance of the bike.