Bike fitting has become sort of a science, incorporating things like hip angles, precise measurements, and wind tunnel aerodynamic data. While all these things can help dial in your exact fit that is the absolute best position for your body, there are some simpler things to look at to get the basics and make sure your bike is set up pretty well. Here are a couple quick tips!
First, seat height is one of the most important. If you can’t reach the pedals, how are you going to ride the bike? To make sure your saddle is set to the right height, sit on your bike and put your foot at the farthest point of the pedal stroke. With your foot is at this point and level with the ground, your leg should be just short of fully extended. This way, you aren’t over reaching for the pedal, but at the same time, not eliminating some of the range of motion in your hip by not having the pedal far enough away.
The second thing I’d like to look at is stand over height, which can tie in a little bit to saddle height. If you stand on the ground with the bike between your legs, you should be able to actually stand over it. If the top tube is too tall to stand over, the bike may be a bit too tall for you.
The reach from the saddle to the handle bars is the next thing I’d like to touch on. If your bars are too close, or too far away, your bike is going to be pretty uncomfortable, especially when you are riding for a long time. Ideally, when your hands are on the brake hoods, your elbows should be able to be slightly bend and your shoulders should not be rounded forward. This way, you aren’t straining your whole upper body in order to grab the handle bars when you ride, which can put a lot of unwanted stress on your arms and neck.
The last thing I’d like to touch on is the handle bar height. Now, this is a factor that changes from person to person and has a lot to do with the rider’s flexibility and willingness to get aggressive or relaxed. The lower the drop is from the saddle to the bars, the lower your body will be on the bike, and the more crouched over you will be sitting. Due to flexibility differences, some rides can get into more aggressive positions than others. While a lower position is more aerodynamic and usually allows for better handling, it can be more uncomfortable than sitting up higher in a more relaxed position. It all comes back to personal preference.
I hope this helps you make sure you have your bike set up in a position that is right for you!