Just count the number of sprockets at the rear hub, then look/ask for a chain for that number of speeds. Keep in mind that all chains are sold long, and usually have to be cut to size when fitted. If you haven't got a chain breaker tool yourself you might as well have the store replace the chain while you're at it. Also keep in mind that chain and sprockets wear together, and to avoid further troubles, is't often best to replace both at the same go.
No there is no such thing as a 21inch bicycle
Neither is better than the other It's simply down to personal preference Some factors to consider are: 20 inch bikes are easier to jump and you can jump higher 24 inch bikes are better for jumping large gaps on, and will often have better brakes than 20 inch bikes (20 inch bikes usually have U brakes while 24 inch bikes have disks)
Mountain bikes have a taller scale than 20 inch bikes, but are better suited for outdoor ruggedness.
There are website that go into a lot of detail on this. However I have a 30 inch inseam and I take a 58 cm road bike or an 18 inch mountain bike. Road bikes are measured in cm, moutnain bikes in inches.
Typically the size of a chain on an adult bike should be one 16th of an inch or less. It is recommended to replace the chain on your bike if it exceeds one 16th of an inch.
There are several options to that question. If you're talking about frame size on a MTB, then 20" would be a large bike. If you're talking about 20" wheel size, then it's probably a BMX which is a fairly small bike.
for a 12yr that's a beginner try to go with something not to heavy focus around between 26lbs and 28lbs. I think the kink launch would be a good bike for a 12yr old or the fit am would be even better. The eastern shovelhead would be good to!
More than one type of bike can have 24" wheels. Some DH MTBs(downhill mountainbikes will have that, and some trials bikes. It can also be the last size available as a kid's bike. It can even be a compromise for someone who wants a folding bike with decent ride characteristics.
Depends on how high you're hoping it will go. An inch or two shouldn't be a problem, but that's a chunky bike to bunnyhop.
what ever size fits them for their intended uses.
The best price you can get for a 24 inch Schwinn bike is $202.43.
Wheelie bikes ( which is a slang term for "high rise" bikes) were first sold commercially in California U.S.A. back in Feb/March 1963. The first factory made wheelie-bike (or high-riser bike) was the Huffy "Penguin". Made at Huffman Manufacturings Azusa California bicycle factory. The Penguin bike was made for California bike distributor Pete Mole, of the "John T. Bill" Company. The bike was made to Pete Moles specifications which included 20 inch wheels, a cantilever frame, a "Persons-'Solo Polo seat'" , and Wald brand high riser handlebars. The Schwinn "Sting-Ray" wheelie bike was officially released in June 1963, and was almost identical to the earlier Penguin bike, except for color. ...........John Brain.