FSA FLOWTRON Dropper Post Reviewed
Full Speed Ahead's 150mm FLOWTRON dropper post is a great addition to the increasingly crowded 250 USD uppy-downy post price zone. Of particular note is the forward-thinking clamp layout that helps deliver that modern over-the-bottom-bracket pedaling position even on bikes that are over-forked or have slacker-than-cool seat tube angles.
I love the direction posts are moving. There are some standout high-end posts like ReVive but I have loved watching the general travel and reliability go up while prices come down. The more competition the better and the FLOWTRON is a worthy contender.
In addition to the now familiar Wintek cartridge layout, FSA adds multiple leverage options to vary the feeling of the remote (highest leverage for the win), the forward saddle clamp orientation, and a really clean one-piece shaft/head.
The FLOWTRON suffers with the same issue as Bontrager's equally priced Line. It's a great seat post, and a solid value, with the same name as a crappy product that proceeded it. It's hard to blame either brand. FLOWTRON is a pretty good name that has me thinking 1986 Transformers movie every time I say it and 'Line' items are ubiquitous for Bontrager. I never used the earlier iteration of FSA's dropper post, but it's pretty easy to say that this is the product they should have put out originally.
When I push the FLOWTRON down manually, it's not as smooth as Gucci options like the ReVive or the Fox Transfer. That doesn't matter a whit in the woods when I push the button and slam my ass onto synthetic leather and this post is actually best compared to more expensive options out on the trail. In the months I've been riding the post it has undramatically returned my saddle to climbing height with every activation. It goes down when I sit on it, and it's stayed nice and tight. That meets my action expectations.
Return speed is acceptable but much slower than the race-rocket return of my e13 TRS+ or any adjustable air-sprung posts I've used. It's a touch faster than the Crankbrothers Highline and a bit slower than the Bontrager Line. If you like it fast you will find the FLOWTRON slow. I know from the Highline review that a slower return speed is a conscious choice because Wintek cartridges last much longer with a lower charge in them.
The shaft has developed a little bit of play compared to when it was brand new but it's minimal, even compared to much more expensive options. As with the Line, the balance of free-play vs. return-friction is very well balanced.
Of the myriad posts swimming in the FLOWTRON's pond, it could have one of the best stock remotes. I like the big paddle and solid leverage whether using it with FSA's light-action setting or with other posts with stiffer actuation.
Unfortunately the FLOWTRON doesn't mesh well with my combination of Presidential thumbs and Magura HC brake lever blades. When I have my brake levers in their magic spot the FSA remote sits either too close or too far away from my thumb for peak initiation. The easy solution is to adopt a two position clamp like the excellent, and MatchMaker compatible, e13 TRS+ remote or a sliding clamp position like the Wolf Tooth ReMote. In the former example the remote wouldn't look as clean but it could be done without an increase in price.
If the FSA remote interfaces well with your brake levers, for example inside on a Shimano M8000 lever or outside of a TRP Quadiem lever, then I think most riders will be happy with the stock unit. Since the FLOWTRON remote didn't work perfectly with my setup, as with other posts, it would be great if FSA sold the remote separately. If I could pick up this post for 200 USD and choose my own remote that would be ideal.
Do The Teardown
I always learn a lot by taking things apart. Forks, shocks, dropper posts, hubs, disc brakes - all big purchasing decisions. As with most dropper posts with a Wintek cartridge, the FLOWTRON is a pleasantly simple chassis and actuator setup. Spare parts are available in modules; seat clamp assembly, cartridge, tower/actuator assembly, shaft, body and a service kit that includes seals and keyways. If you'd like a look at the inner workings please check out the original teardown article. As always, a big thanks to my friend Jeff of Bikeroom & Wheelthing fame for stepping up with tools, insights, and expertise.
Even if the cartridge is still working great I'd suggest stripping down the FLOWTRON, and any similar dropper, at least once a year* for a clean and re-lube. Any handy rider with some common tools and time can handle this job at home. It's also something that will be quick and easy for your local shop to pump out.
*In my experience you know who you are if twice a year is a more appropriate service interval.
Outside of FSA's 2yr warranty, a new cartridge is 50 USD. It's also possible to lower the post from 150mm to 125mm by purchasing a different cartridge. It's not as simple as installing a spacer but it's still much more economical than buying a new post if a rider finds less drop is desirable.
FLOWTRON. It comes up and stays up. It goes down and stays down. It stops anywhere in the middle. It's going to do that for a tonne of hours of riding and it's easy to service with no proprietary tools or knowledge.
From what I've seen, Wintek owns the dropper post game when it comes to balancing reliability vs. performance vs. simplicity vs. lifetime cost of ownership. While the Crankbrothers Highline is the best example of a Wintek-driven post I've ridden, the FLOWTRON is a great product for 100 USD less.
It would be great if FSA follows up with a 170mm version, since steeper effective seat angles call for more saddle drop when descents get hot and heavy. My experience with this 150mm version leads me to think scaling up would be easy for Full Speed Ahead.
In the meantime, anyone chasing dropper post value in a 30.9 or 31.6 post with 125mm or 150mm drop would do well to put the FLOWTRON on their list.