TranzX EDP01 Seatpost

While wireless components are steadily growing in popularity (and performance), there is still a lack of relatively affordable options in the wireless dropper space. TranzX is looking to remedy that as the first company to offer a $500 wireless dropper post, eloquently named the EDP01. We’ve had one on test for five months now, and we’re here to report on how we’ve been getting along. Keep reading to find out!

TranzX EDP01 Highlights

• Travel: 150, 170 and 200mm
• Diameters: 30.9 and 31.6mm
• Sealed adjustable air cartridge
• Bluetooth 5.0 wireless connectivity
• Automotive grade IPX 66 rated water resistance
• Rechargeable lithium-ion battery for the post
• Lever remote uses common CR2032 battery
• 0mm offset post head with secure 2-bolt saddle clamp
• Weight (post): 721 grams (31.6/170, verified)
• Weight (remote): 53 grams (verified)
• 1-Year warranty
• MSRP: $499 USD

Initial Impressions

And so there were three. The EDP01 joins the RockShox Reverb AXS and the Magura Vyron MDS-V3 among the commercially available wireless droppers today (KS also has a wireless post now that should be shipping soon), and it’s aiming to make a splash by coming in significantly cheaper than the others. At $499 USD it is $360 less than the Reverb and about $120 less than the Vyron, and it also gets closer to the prices of the most expensive mechanical droppers out there at present. At 720 grams for the post, including battery, the EDP01 is about 20 grams heavier than the RockShox and the Vyron, at the same dimensions.

The EDP01 builds on the architecture of the current TranzX mechanical posts, relying on a closed internal cartridge to control the post’s movements. The cartridge looks similar those used by many other dropper posts on the market today, but TranzX says they had to modify it somewhat to play nicely with the electronic activation (as usual, the affordable replacement cartridges will still be available to purchase should something go wrong with it outside the one-year warranty period). The cartridge is activated by a small battery-powered motor situated in the post head housing, which connects to the handlebar mounted remote via Bluetooth.

The finish of the post and the remote are acceptable – not as refined as a Reverb AXS, but everything feels solid and well put together. The head uses a single-clamp mechanism with a separate bolt for adjusting the seat angle. The housing is IPX66 rated which corresponds to automotive-grade water resistance (not enough for prolonged submersion but certainly up for life on a mountain bike). The remote is small, and while the lever blade feels a bit flimsier than an AXS pod, the overall execution feels “good enough” at this price point.

As for the dimensions of the post, it seems like the batter/motor housing has added about 10 mm to the head height, but other than that the EDP01 is fairly compact. Note that because there is no cable to connect at the base, the EDP01 may well fit deeper into some frames than a cable-actuated post, even if the latter is shorter on paper. Here’s a table comparing the key measurements of the EDP01 to some of its mechanical competitors (weights include posts, remotes, and cables):

On The Trail

Installing a dropper post without having to deal with internal cable routing is always a huge plus, and the novelty of it all hasn’t quite worn off yet – stoke levels are high when you can just slip the post into the frame, attach the remote to the handlebar and go ride (we mounted ours to a SRAM brake via the MatchMaker interface, but there’s a handlebar clamp included in the box if need be). Our units were already paired out of the box, otherwise there’s a fairly simple pairing process to follow should that not be the case. One thing we noticed early on is that the post body is very smooth, which made it difficult to keep it from slipping in the seat tube. We ended up having to use some carbon grip paste, but even then it took a few rides for the surface of the post body to develop enough grip to stop slipping.

The first question we were eager to get an answer to was “how fast is it?” – we’re talking first and foremost about the speed of actuation here. The good news is that TranzX has managed to minimize the delay between pressing the lever and the motor activating the cartridge mechanism. A distinct motor sound accompanies the action to further underscore the fact that no cables are involved in this process anymore. You can see the post in action here to get an idea of the actuation speed:

The second aspect of reactivity is of course the actual speed of the post’s movement. Once you press the lever and activate the cartridge valve mechanism, the post is easy to compress and drops down about as fast as you could ever want it to, modulated mainly by your weight on the saddle. The valve closes quickly once you let go of the lever, making it pretty easy to stop the post at any point in the travel. You can use little taps on the lever while sitting on the post to drop it in small increments, which is pretty useful. As for the return speed, we found it on the slower side even when maxing out the air pressure in the cartridge. We would like to see TranzX speed things up here a little bit, and also implement a more distinct top-out sound to enable the rider to quickly and easily tell when the post has reached full extension. As it stands, we were often left guessing which meant waiting an extra fraction of a second before releasing the lever at max extension just to be sure.

Battery life has been excellent so far, we’ve gotten close to a month of use out of one charge while going on ~4 rides per week. We did run out of juice on the trail once, and we were a bit disappointed to see that the post had failed to provide any kind of adequate warning in regards to the dropping battery level (the LED light is supposed to turn red when that happens, but ours didn’t do that – perhaps a future firmware update will sort this issue out as that functionality is mentioned in the user guide). When our battery died, the valve ended up in the open position which was extra annoying (the motor is responsible for both opening and closing the valve, so it won’t default to the locked position when it runs out of power, which would probably have been preferable). Recharging the battery takes about 90 minutes from empty to full.

To summarize our on-trail and ownership experience so far, the overall impression of the EDP01 is very positive. The post is simple to operate and reliable in action, and we’ve gotten very used to the light touch required to press the lever - to the point that mechanical dropper levers are starting to feel quite clunky and demanding, even the best ones…definitely a first-world problem if ever there was one! With a faster return speed the EDP01 would be nearly perfect, as it stands, it’s still very good.

Things That Could Be Improved

We’ve mentioned the slow return speed already, and that would easily be number one on our list of things to improve. It also seems like the LED on our post isn’t behaving exactly as intended, as it doesn’t seem to change color as it should when the battery level drops.

Long Term Durability

After 5 months of pretty intense riding (~4 rides per week), the EDP01 is still going strong. Bushing play has not developed beyond the small amount that was present from the start, and there is absolutely no sag in the cartridge at this point (it also still feels very solid when picking the bike up by the saddle, even with the post down). The post head has remained free of any creaks and we have not had to readjust our saddle in any way since we started testing. The actuation mechanism works exactly like it did on day one too. With replacement cartridges and bushing/guide key refresh kits readily available as well, it looks like this one should be able to serve you for seasons to come. We’ll keep ours running and will report back if anything unexpected should pop up at a later point in time.

What’s The Bottom Line?

Wireless components are definitely a bit of a luxury, but that doesn’t mean they don’t have their advantages. A wireless dropper is blissfully easy to install, and it is also very comfortable in use. We really like the low amount of hand/finger movement required to activate the lever of a wireless dropper (the same goes for wireless shifting BTW), and the minimal lever throw makes it very easy to really dial in the position of the lever on the handlebar. The TranzX EDP01 offers very good performance at a new price point in this market segment – $499 USD is still a fair chunk of change but if you’re looking to get into the wireless dropper experience this is by far the most affordable option currently available. We’d love to see a faster return speed of the post itself, but the wireless actuation is quick and intuitive in action. Certainly one to consider!

More information at: na.tranzx.com.

About The Reviewer

Johan Hjord - Age: 50 // Years Riding MTB: 18 // Weight: 190-pounds (87-kg) // Height: 6'0" (1.84m)

Johan loves bikes, which strangely doesn’t make him any better at riding them. After many years spent practicing falling off cliffs with his snowboard, he took up mountain biking in 2005. Ever since, he’s mostly been riding bikes with too much suspension travel to cover up his many flaws as a rider. His 200-pound body weight coupled with unique skill for poor line choice and clumsy landings make him an expert on durability - if parts survive Johan, they’re pretty much okay for anybody. Johan rides flat pedals with a riding style that he describes as "none" (when in actuality he rips!). Having found most trail features to be not to his liking, Johan uses much of his spare time building his own. Johan’s other accomplishments include surviving this far and helping keep the Vital Media Machine’s stoke dial firmly on 11.

Photos by Johan Hjord and Nils Hjord