Advantages of using a mountain bike without gears include simplicity, lower maintenance, and potentially lower cost. Disadvantages may include limited speed options, less efficiency on varied terrain, and more physical effort required when riding uphill.
Advantages - Spur gears are simplest, easiest to design and manufacture and disadvanages i dunno :)
Advantage: much easier to select between gears without having to double-clutch. Disadvantage: for a given gear-pack size, synchro'd gears are weaker.
A mountain bike with no gears is simpler to use and maintain, lighter in weight, and less expensive than bikes with gears. It can also provide a more challenging workout and improve your biking skills.
Because the speed is decreased less from an equal gear ratio.
Bikes with internal hubs have advantages over bikes with external gears in terms of low maintenance, protection from weather, and ease of use. Internal hubs require less maintenance, are protected from weather elements, and provide a cleaner look without exposed gears.
The advantages of using a Shimano twist shifter for changing gears on a bicycle include easy and quick gear changes, intuitive operation, and the ability to shift gears without taking your hands off the handlebars, providing a smoother and more efficient riding experience.
high drag
A tricycle with gears offers the advantage of being able to adjust the resistance level when pedaling, making it easier to ride uphill or against strong winds. This can provide a more comfortable and efficient riding experience compared to a tricycle without gears, which may require more effort in these situations.
The advantages of using a Shimano Alfine hub for cycling include smooth shifting, low maintenance, and a clean look without external gears.
Depending on the mountain bike that you have will depict the amount of gears. Most bikes for adults typically have about 21 gears. If this does no answer your question then what are levels?
Changing Gears Flagstaff and the Mountain Bike - 2011 was released on: USA: September 2011
Using high gears on a bike can make pedaling easier and faster, which is advantageous for riding on flat terrain or going downhill. However, it can be harder to pedal uphill or start from a stop. On the other hand, low gears make it easier to pedal uphill or start from a stop, but can make it harder to pedal at high speeds or on flat terrain.