To measure the frame size of a mountain bike, you need to measure the distance between the bottom bracket (the center of the pedal crank) and the top of the seat tube (where the seat post inserts into the frame). This measurement is represented in inches and is commonly referred to as the seat tube length. You can measure it using a tape measure or ruler. This measurement will help you determine the appropriate size of the bike frame that fits your height.

A mountain bike can be used for street riding, but it may not be the best suited for such a purpose. Mountain bikes are designed for rough terrains, with features like suspension and wider tires, which can make it slower and heavier than other types of bicycles. However, it can still be a good option for those who enjoy off-road cycling and occasionally commute or ride on paved roads.

Assembling a Mongoose mountain bike requires a few tools and attention to the instructions provided by the manufacturer. First, install the front wheel and attach the handlebars to the stem. Then, install the pedals, seat, and adjust the height of the seat post. Check the brakes, gears, and tire pressure before taking your bike out for a ride. It is recommended to have a professional bike mechanic check your assembly work before using the bike for the first time.

To fix a bent rim on a mountain bike, first, remove the tire and inner tube from the rim. Then, secure the wheel in a truing stand or use a zip tie as a makeshift gauge. Locate the spot where the rim is bent and use a spoke wrench to adjust the tension on the affected spokes, pulling them slightly to straighten out the bend. Make sure to check the trueness of the rim frequently until it is properly aligned. Once finished, re-install the tire and inner tube.