Travel refers to how much the post slides up and down, and it dictates just how far out of the way you’ll be able to get your saddle while still having the best position for pedalling.

Less expensive posts often have less travel. The longer the travel, the stronger and more precise the internal mechanisms have to be.

The starting point for most dropper posts is 100mm. That amount of drop makes a noticeable difference, but we’ve found that longer-travel posts do a much better job of maximising the clearance while maintaining a proper seated pedalling height.

The typical amount of drop is around 125mm to 170mm of travel, which works well for most riders.

Longer-travel posts do exist, from 170mm up to 210mm, but they can be difficult to use for shorter riders or on certain bike frames. That said, longer-travel posts are becoming more and more common as technology improves and bike manufacturers design frames with shorter seat tubes.

To figure out how long a drop you can use, measure your existing seatpost from the saddle rail to the top of seat collar, then compare this to the length of the dropper post from the saddle rail to below the post’s collar.

If the number is the same or less, you’re in business. If the dropper post’s length is longer, you’ll have to use another option.

Fixed or infinite travel adjustment?

There are two travel styles for dropper posts: those that have fixed height settings where the post stops (20mm down, 75mm down, etc), and those that do not, often referred to as stepless or infinitely adjustable.

Stepless posts enable you to stop the saddle anywhere within the post’s travel range. The majority of posts on the market are stepless designs.

Dropper seatpost internal workings

All posts require some sort of spring to return the saddle to the fully upright position and a locking mechanism to hold it in place.

Early designs simply used coil springs and pins to do the job, but these were less refined and often returned the saddle back towards your bottom at an unnerving speed.

You can still find mechanically locking designs with an air spring, but most dropper posts now use a fully sealed hydraulic cartridge that contains both a pressurised charge and a mechanism that allows the adjustment.

There are a number of advantages to this, namely that the body of the post, which needs to cope with very heavy loads, doesn’t also have to be airtight and so lower-friction seals can be used for a lighter action.

If something does go wrong with the post, it’s also much quicker and easier to switch in a replacement cartridge rather than repairing the entire post.

Dropper seatpost remotes