structural:expansion
2000s–2020s

Following the growing trend in 29-inch wheels, there have been other trends in the mountain biking community involving tire size. Some riders prefer to have a larger wheel in the front than on the rear, such as on a motorcycle, to increase maneuverability. This is called a mullet bicycle, most common with a 29-inch wheel in the front and a 27.5-inch wheel in the back. Another interesting trend in mountain bikes is outfitting dirt jump or urban bikes with rigid forks. These bikes normally use 4–5″ travel suspension forks. The resulting product is used for the same purposes as the original bike. A commonly cited reason for making the change to a rigid fork is the enhancement of the rider's ability to transmit force to the ground, which is important for performing tricks. In the mid-first decade of the 21st century, an increasing number of mountain bike-oriented resorts opened. Often, they are similar to or in the same complex as a ski resort or they retrofit the concrete steps and platforms of an abandoned factory as an obstacle course, as with Ray's MTB Indoor Park. Mountain bike parks which are operated as summer season activities at ski hills usually include chairlifts that are adapted to bikes, a number of trails of varying difficulty, and bicycle rental facilities.

In 2020, due to COVID-19, mountain bikes saw a surge in popularity in the US, with some vendors reporting that they were sold out of bikes under US$1000.