29 inch - What does that actually mean?
Some readers ask what actually constitutes a 29-inch wheel and what the difference is to a 28-inch wheel. The BIKE test department explains what 29-inch mountain bikes are all about.
Reader question: Is it correct that the outer diameter of 29er wheels without tyres is the same as that of 28-inch wheels? I have read that the 29ers are called that because the diameter of the wheel with tyres is approximately 29 inches.
Answer from Christoph Listmann, BIKE Test Manager:
That is correct, the 29 inch wheel circumference is due to the tyre. Fat 29er tyres actually result in 30 inches. So you can also put narrow 28" road tyres on a 29" MTB - some professionals do this, by the way; they no longer ride a road bike in road training, but their 29er bike with road bike tyres. The advantage: they retain their usual position and benefit from the disc brakes, which are ultimately much more powerful than road bike brakes.
