Fitting 700c Wheels on a Mountain Bike
It is a known fact that bikes are available in different types, sizes, and shapes. One of the factors determining if a bike is likely to perform is the size of its wheels. Since most bikers want to optimize their cycling performance, every biker needs to get the right size wheels for their bike.
Tires and inner tubes come in a wide array of sizes, and it can be confusing even for experienced bikers. Some of the things that you need to know about the bike wheel are stated below.
Bike Wheel Sizes- 700c vs. 27-inch
The difference between 700c and 27-inch is quite small as the rims are 622mm and 630mm respectively, while the actual change in brake shoe position is 4mm.
Although 27-inch and 700c tires look similar in size and the inner tubes are compatible, you cannot use a 27-inch tire on a 700c wheel and vice-versa. Some of the things to know about them are stated below.
700c Wheels
700c wheels are the modern standard for cyclocross, road, and numerous hybrid tires. They are also common in some European-style cruiser bikes. 700c wheels have outer diameters which vary based on the type of tire and tread pattern. However, the inner diameter is the same.The 700c tire has a Bead Seat Diameter (BSD or inner diameter) of 622mm. Many of the high performance 700c road bike tires have a width of 23-25 mm, although the range could be anywhere from 18-28mm. Cyclo-cross and touring 700c tires range from 28-38 mm, while those on hybrid bikes may go from 35mm all the way up to 45mm.
27-inch Wheels
27-inch wheels can be commonly found in some older road bikes. Many of these 10-speed bikes were produced in the 1980s or earlier. While it is rare to find 27-inch wheels on modern bikes, it is still possible to source for inner tubes, wheels and replacement tires.The 27-inch tire’s BSD is 630mm. They mainly come in widths of 1-1/8 inch, 1-1/4 inch, and 1-3/8 inch.
Difference Between 26-inch Wheels and 700c Wheels
26-inch wheels tend to be fatter, and are commonly found on mountain bikes. The wheel gives a bike more cushion because there is more air volume to disperse once you go over bumps.700c tires are usually narrower than 26-inch wheels, and are commonly found on cyclocross, hybrid, and road bikes.
700c on a 26 Frame
Since 700c has a larger diameter than 26-inch wheels, if you are planning to fit 700c on a 26-inch frame, you might need to replace the brakes.
Although some cyclocross bikes use V-brakes, you may not find a brake that will fit into the 26-inch frame because the mounting points are usually in different places. However, you can try and fit some deep drop dual-pivot brake calipers or use a bracket so you can fit it higher up.
Another issue with fitting 700c into the 26-inch frame is the rear axle width. This is because most 26-inch wheels are 135mm, while 700c wheels are 130mm. You can fix this by using a longer axle and re-space it or adjust your frame to the narrow setting.
Here is a video showing how you can fit 700c wheels onto a mountain bike, with some tools such as brake post extenders and a rear axle adapter (Credits to RJ The Bike Guy):
Summary
Not every mountain bike would be able to fit 700c wheels nowadays. You would be better off checking the outer diameter of your mountain bike’s default wheel, and if the difference is not too exaggerated, you could try swapping the wheels.