Lenghts and angles differ and are important when fitting a bicycle to suit a rider.
Road bike stem length measurement.
On stems with built in rise this measurement will be made along an imaginary line as seen in the diagram.
Whereas road riders tend to choose stem length based solely on overall bike fit and positioning for off road riders the length of the stem is critical in determining how the bike handles.
We often refer to this as the stem length.
Riders like to get a long small and aerodynamic position of the bike e g spirited racers can choose for a longer 1200 mm stem for optimum stretch.
Sometimes you might need to customise the stem length yourself though.
Important dimensions and how to measure.
However most stems are not marked and must be measured in order to determine size.
Stem length will vary with the design of the bike.
Stem length designated in millimeters may be indicated on the stem.
In order to alter stem length you must first know the length of your current stem.
Some manufacturers specify different length stems in relation to the frame size to try and offer the best fit.
Good bike shops will be very helpful in helping you get the right stem length on your new bike or buying a new stem doesn t have to cost a lot of money.
Picture 2a shows a quill stem with a shorter neck angled downwards next to a threadless stem with a longer neck.
The effective length of the stem measured from the centerpoint of the steering bore to the center of the handlebar clamp without accounting for rise.
The wrong stem length will not only make it difficult to reach for the handlebars it will also destabilize the steering and affect body position on the bike.
Stem length is one aspect of a road bike that you can alter to increase both comfort and performance.
It must also address the rider s comfort biomechanics performance needs and the steering and handling of the bike.
Shorter stems result in noticeably quicker and more responsive handling that is a definite advantage on technical singletrack and gravity riding.
The best average stem length for modern mountain bikes falls between 50 mm and 80 mm.
Road bike stem length guide bike stems look like a standard equipment without any science to it however they are highly influential when it comes to comfort and control.
Stems are made with various lengths and angles.
Generally speaking stem lengths on road bikes vary from 80 to 140mm with 100 to 110mm perhaps the most common sizes.