As the first of hopefully many articles I’ll give a brief scope of kinds of cycling and then talk about sizing a bike correctly.
Pretty much everyone on the face of the planet has seen a bike at one point in their lives. It is such a vital invention that it can be found everywhere from the most impoverished countries to the richest in the world. Throughout its life the bike has spawned off into many different variations to meet the needs man.
For our purposes here biking can be broken down into 3 main categories-road riding, mountain biking and touring. There are of course others variations such as BMX, cyclocross etc. but I’ll choose to focus on these 3 first. Most Americans would closely relate road racing to the Tour de France. The goal is to have the lightest cycle possible and go as fast as you can. By contrast mountain bikes were designed to cover rugged wilderness that a road bike with skinny tires never could. Finally bike touring is where riders cover large swatches of land carrying saddle bags (most call them panniers) and camp each night before moving on.
Remember the kind of riding you plan on doing dictates what kind of bike might appeal to your sensibilities. The choices are varied so you’re almost guaranteed to find a flavor of cycling that you like. However, always remember a free bike is the best bike! If you happen to get something for free don’t fret if its too small, too big etc. At some point everyone has ridden incorrectly sized bike. But as you get more serious you may want to properly size a bicycle frame to your body. Riding the bike you plan on getting is always the best bet but you should have some background knowledge to inform your decision.
I really like the tool over at Ebicylces for figuring out your frame size. (http://www.ebicycles.com/bicycle-tools/frame-sizer)
To use this calculator you need two measurements-your height and your inseam. To measure your inseam put a hard cover book between your thighs. With your feet spread shoulder width apart measure the distance between the floor and the top of the book. By putting your information into this calculator you will get a range of sizes, not just one. Its very important to note that frame sizing is subjective!!! Its all up to what feels right to YOU!. Thus there will probably be about 3 size options the calculator presents you with. Sizing is great to optimize energy output and make riding easier but it comes down to preference as well.
Some bikes indicate frame size by a sticker or marking. Some do not. The most common way to measure a frame yourself is to take a tape measure and do the following-measure the distance between the center of the crank and the top of the seat tube. Different people and companies do this, but this is a good general rule of thumb. (Note-Bikes with slanted top tubes are measured a little different. If the top tube of the frame triangle is horizontal this advice applies)
*Please keep in mind that sizing should never prevent you from riding a bike. 9 times out of 10 adjustments can be made to make the bike work. Take what you have and make due. Keep riding
-Terence William for Bike and Brain