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FSA Flowtron AGX gravel dropper post review

Adjustable seatpost for gravel and beyond

Our rating 
3.5 out of 5 star rating 3.5
GBP £270.00 RRP | USD $263.00 | EUR €262.00
FSA Flowtron AGX dropper seatpost for gravel bikes

Our review

The Flowtron is proof that a dropper seatpost isn’t just for mountain bikes
Pros: Ergonomic thumb lever with custom tension
Cons: Return spring isn’t adjustable and lacks power
Skip to view product specifications

First, a full disclosure: I haven’t ridden on a mountain bike without a dropper post for about 10 years. But an adjustable seatpost on a gravel bike?


The advantages on more technical terrain are obvious. Dropping the saddle gives increased confidence to your handling, enabling you to move your weight around much more, avoiding the restrictions you experience when the saddle is at full height.

It’s away from that terrain, however, that the advantages of a dropper seatpost on a gravel bike are a surprise. For example, lowering the saddle on road descents changes the balance and makes you go faster and become more stable. It’s great for easy dismounting at gates, too.

The FSA Flowtron AGX has a 27.2mm diameter (making it compatible with most gravel bikes), 100mm of travel and a remote lever that works with drop bars.

Out of the box, you need to be aware that you will need at least 164mm of exposed seatpost for this to fit your bike. Also be conscious that the internal cable routing takes time and care to set up.

You’ll need to remove the bar tape to put the lever clamp in place and, depending on your bike, you may need to remove the chainset and bottom bracket to get the cable from down tube to seat tube. If you’re unsure about how to do this, we recommend getting your local bike shop to fit it for you.

FSA Flowtron AGX dropper seatpost for gravel bikes
The remote lever has adjustable tension and can be positioned to be accessible from riding on the drops or the brake hoods.
Russell Burton / Immediate Media

It’s possible to adjust the tension on the lever to firmer/softer, but a word of caution: the adjustment is made at the base of the post so don’t complete your set up, cut the cable and re-tape your bars before deciding you want to change it.

Likewise with the lever, because it can take a few tweaks before you align it just right for accessibility from both dropped and hood riding positions. It’s important not to cut anything until this is done.

The rate of the spring is fixed and in dry weather that hasn’t proven to be an issue, the response has been immediate with no break in ride flow. However, in wet or muddy conditions, dirt or grit can slow the response. The saddle becomes unwilling to return and the spring isn’t strong enough to overcome it. Adding a saddle bag causes the same problem.

Are these niggles deal breakers? Certainly not. In a relatively short time, I have assimilated the dropper seatpost into my gravel rides easily and I don’t want to go back, thank you very much.


Personal choice will dictate whether it’s for you or not, but my advice is not to assume that droppers only have a place on more technical terrain.

Product Specifications


Price EUR €262.00GBP £270.00USD $263.00
Brand Fsa


Remote Yes
Seatpost diameter 27.2mm
Travel 100mm