Trek Top Fuel 9.9 XX1 AXS

A dropper seatpost allows you to quickly lower and raise your seat to give you an ideal riding position. Dropping your seat creates a lower center of gravity for better control and maneuverability on steep descents, while raising it puts you at normal riding height for efficient pedaling.

Construction can include either hydraulic- or cable-actuated systems and the post’s travel can either be infinitely adjustable or stopped at set intervals, depending on the model.

Dropper seatposts come in standard lengths and diameters and vary by the amount of travel.

Electronic drivetrain systems deliver excellent shifting, easy set up, and solid battery life. Here are the highlights of today’s electronic shifting systems:

Shifting Performance
Electronic shifting systems use powerful servomotors to rapidly shift the chain. Because microprocessors and sensors constantly monitor every aspect of the system, they shift with precisely and without chain rub.

Customization
Many major systems have customizable shifting. Some have the ability to add remote shifters for common riding positions, and some even allow you to change the functions of the shifting buttons.

Dependability
Electronic groupsets are responsive and consistent. There are no cables to stretch and wear out, so you get a flawless shift every time. The added bonus is you’ll never have to replace a derailleur cable ever again.

Will my bike have a curved top tube?

Smaller frames (S) have a top tube that dips down as it approaches the seat tube. This design makes for a lower standover height, which is good for shorter riders because it allows them to straddle their bike more easily. Larger frames (M and up) have a straight top tube because taller riders with longer legs typically don’t have the same issues with standover height.