The length of the head tube is measured from the bottom to the top. Long head tube bikes elevate the front end of the bike, placing the rider in a more upright posture. Short head tube bikes lower the front end of the bike, lowering the rider's frontal profile and boosting aerodynamics. Head tube length varies depending on whether it is steel or titanium, but generally speaking, longer head tubes are used on premium bikes that cost more money. Head tube length is one factor among many that influence how a bike feels when you ride it. For example, long head tubes make for a more aggressive riding position.
Bike manufacturers usually specify head tube length as a number of inches or centimeters. The number may refer to the total length from the center of one tube to the other, or just the outside diameter if both tubes are equal size. For example, a number-five headset means that the head tube length is 5 inches (or 127 mm) long.
The head tube is the part of the frame that holds the wheel bearings and forks/rear dropout. It can be made of aluminum, carbon fiber, or steel. Longer head tubes tend to be heavier than shorter ones because they require thicker walls that are stronger but also more expensive to manufacture.
Head tube length affects how your bike handles by determining its "geometry".
Pros often ride bikes with top tubes ranging in length from 20.5 to 22 inches. Shorter riders, including children, often have a top tube length of 18 to 20 inches. A pro-size bike's top tube measures 20.5 to 21 inches in length. Older pros may have shorter top tubes because of age or injury; some older pros report that they are able to finish strong races on bikes with top tubes as short as 17.5 inches if they're not trying to win or place highly.
The majority of pros we talk to prefer full-suspension bikes. These bikes give better traction and control in dirt and loose gravel courses than their hardtail counterparts. However, most experts agree that it's possible to race successfully on either type of bike. It just helps if you like to get sideways sometimes!
Full suspension bikes tend to be heavier than their hardtail counterparts, but this is generally considered an advantage by professionals because it gives them more stability while riding over rough terrain. Pro riders also love their suspensions because it improves wheelieing performance.
Length of the top tube
Frame height is the length of the seat tube from the bottom bracket (crank bearing) to the top tube in general. The term “frame size” refers to this measurement. Frames come in different sizes, depending on the distance between the bottom bracket and the top of the head tube. These sizes are usually expressed in centimeters or inches. For example, a 50-cm frame is about 19 inches tall.
Bike size depends on two factors: how far down you want your handlebars to reach and how long you want your bike to be. If you want shorter handlebars, go with a smaller frame size. If you need a longer bike, try a larger size. There are typically more options for headsets and frames than for other components. This is because headsets and frames are made in multiple sizes, while other components often only come in one size.
Frames are either straight or sloping. Straight frames have a horizontal top tube, while sloping frames have a downward angle between the top and bottom tubes. This determines how easy it is to mount a front wheel and how low to the ground you can position the pedals. Most modern bikes are designed to be ridden with a flat surface under you when you stand up.
"The stem shouldn't have to be incredibly short or super lengthy to fit you." For a proper road bike fit, aim for a reach where your elbows bend slightly while your hands are on the hoods, rather than your spine flexing and bending to reach the bars. A medium-sized stem (about 45mm) will help you keep your shoulders back and your head up when riding into a headwind.
If you wear glasses, ask the salesperson to show you a stem that is not too long. You don't want it rubbing against your nose whenever you ride in a windy condition. A long stem may be necessary if you have small hands or if you prefer to sit more forward on your bike.
Once you find a stem that fits you well, stick with it. There are lots of different shapes of heads and drops for bikes of different types. If you try out several bikes before buying one, you should be able to find one that fits you properly.
There are many factors involved in determining how a bicycle fits a person. Among them are height, weight, position of the hips, amount of torso rotation during cycling, and limb length. In addition, the type of riding you plan to do affects what size bike you need. Factors such as these will help determine how you can best enjoy the benefits of cycling.