Here for the Right Reasons: A TranzX EDP01 Wireless Dropper Post Review – Travis Engel | The Radavist | A group of individuals who share a love of cycling and the outdoors.

The bike industry sure thinks electronic components are cool right now. But Travis doesn’t care if the TranzX EDP01 is cool. He cares if it actually works.

If any component category could benefit from a little more competition, it’s wireless dropper posts. Let’s set the scene real quick: The TranzX EDP01 is up against the Magura Vyron V3, the RockShox Reverb AXS, and the just-released KS Lev Circuit. Magura isn’t bringing the Veyron V3 to the US, but if you really want one, you’ll be paying import duties on top of its €580 ($630 USD) price tag. The Reverb AXS costs $861, and hasn’t seen a fundamental update since it was introduced five years ago. The brand new Lev Circuit debuted at $700, though at the time of writing this, retail availability is still vanishingly thin. So, it’s pretty remarkable that TranzX burst onto the wireless scene with a post that’s been easy to find since day one, and at a price that undercuts the competition by so much.

Quick Hits:

MSRP: $499
30.9 or 31.6 mm diameters
150, 170, or 200 mm travel options
Travel numbers are fixed (no internal fine-tuning)
748 grams for 200 mm (post and battery)
Round 7 mm saddle rails only
“Matchmaker-style” remote and 22.2 mm clamp included
Bluetooth 5.0 wireless connection
CR2032 replaceable remote battery
Proprietary rechargeable 7.4v, 240mAh seatpost battery
Claimed 6,000 activations before recharging
Charger and USB-C cable included
Updatable firmware via nRF Connect mobile app
Adjustable air-pressure cartridge
User-serviceable seals and bushings.
Made in Taiwan
Two-year warranty

Of course, I’m not saying $500 is cheap. For example, the OneUp V3 is a top-shelf dropper post, and it sells for $300 with a remote lever (which all wireless droppers include). So, that’s an extra $200 for the very least expensive wireless dropper you can buy. The jump gets even bigger if you compare the EDP01 to TranzX’s own $224 flagship Kitsuma Air dropper post, pushing the wireless gap up to $276. Again, not cheap, but look at this in a little broader context, and things get interesting.

A SRAM GX AXS kit (derailleur, controller, battery and charger) goes for $633, while mechanical GX derailleur, shifter, and cable go for about $205. That’s a $428 delta for wireless. And yet, the AXS drivetrain has seen pretty wide acceptance. Wide enough that, over just a few years, it has helped literally change bikes as we know them. At an upcharge of “only” $276, the EDP01 just might be what the wireless dropper needs to gain the level of traction that wireless drivetrains have. But don’t worry that mechanical droppers will start to vanish from the market. To be clear, this post is not perfect. There are reasons other than price why a high-quality mechanical dropper might still be a better choice for you. But if you’ve never ridden—or more importantly, never owned—a wireless dropper, lemme tell you; it is a true luxury. In some ways, even more of a luxury than electronic shifting. And the TranzX EDP01 offers a lot of luxury. Kind of surprisingly, in fact.

What’s in a name?

I’d group TranzX together with companies like Velo Enterprises (saddles), or Giant Manufacturing Company (frames, etc.) who make products for multiple different brands. According to the TranzX website, “We’re the largest manufacturer of dropper posts, manufacturing for nearly every top bike brand and many prominent aftermarket brands.” The bike industry, like many industries, often relies on this sort of for-hire production. Many brands we know and love will be in charge of engineering, design, testing, and marketing, but they often contract out their manufacturing to specialty third-party factories. It’s why makers like Paul, Hope, and WeAreOne are so unique. But Velo, Giant, and TranzX are makers, too. Pretty skilled ones, actually. Point is, despite lacking a fancy brand name, the EDP01 was made by people who know how to make fancy dropper posts.

What’s in the box?

That fancy feeling started before I even took the post out of the box. I’m not sure what I was expecting, but the packaging conveys a level of care that I’m more used to from design-forward brands like Crankbrothers or Knog. When most of TranzX’s products probably go out by the pallet-load in plastic bags and bubble wrap, it’s pretty impressive that they took the time to really make you feel like you’re getting a $500 product.

Pulling parts out one-by-one, the remote itself seems a bit bulky off the bike, but more or less blends in once it’s bolted on. At least, it blends in visually. It’s still just stickin’ out there under the brake lever, as vulnerable as any other mostly plastic gadget you might bolt to your bike. But to compare it to the RockShox Reverb AXS (which I’ll be doing a lot), it’s stickin’ out just as far. That AXS trigger has a couple advantages, though. It offers two inboard/outboard positions for a Matchmaker mount, while the EDP01 trigger offers just one. Plus, I liked that the AXS controller requires a bit more force to actuate than the EDP01, while still feeling “clicky.” The TranzX remote runs on a familiar, easy-to-replace CR2032 battery, and the whole system has an IPX 66 waterproof rating, meaning the EDP01 remote can withstand “100 liters per minute of water volume with the pressure of 100 kPa at a distance of 3m for at least 3 minutes.”

Power Up

I was holding out hope that the EDP01 would have been designed around an AXS battery. A lot of the riders buying this post will already have an AXS drivetrain, and it’s nice to be able to swap batteries between dropper and derailleur if one dies on a ride. But SRAM’s patent on how those batteries are mounted means that, even though there are off-brand AXS batteries, we’re unlikely to see off-brand AXS components. It’s a lot like how SRAM doesn’t protect the XD freehub design, but they do protect how a cassette attaches to it. So, TranzX took a fully enclosed approach to their battery, including the charger, which has a real cryogenic-chamber vibe. It uses USB-C, a nice bonus over the standard AXS charger which, at the time of writing this, still uses micro USB.

The EDP01 battery itself is 7.4v / 240mAh, and the AXS battery is nominally a touch higher-capacity at 7.4v / 300mAh. But I’m going to disappoint you if you were hoping for a definitive answer on exactly how long either of these dropper batteries will last. RockShox claims about 40 hours, TranzX claims about 6,000 actuations; I claim I put my battery on the charger about every six or seven rides. The EDP01 battery only died once, but that was on me: If you ever transport your bike from LA to Tucson, remember to remove the battery. Same goes for AXS batteries. The road vibration keeps them awake and drains them quickly.

The post uses a single bolt and locks in its angle with friction. I’ve experienced frustrating binding on other posts with this style of system, making small adjustments difficult, but my EDP01 remains easy to fine-tune after a couple months. Speaking of which, there’s a small secondary bolt that keeps the angle locked in if you ever have to remove your saddle or make fore/aft adjustments, though I almost always just slam my saddles forward.

At the other end of the post is an underappreciated feature of electronic droppers. Since the business end is up at the saddle, the air valve can be at the bottom, so no need to remove the seat to add pressure. I only had to top it off once when I took it out of the box, but it’s still a nice perk. There’s also a thoughtful little collar around the valve that you remove when adding pressure, but protects it if you run your post down near your seat tube’s bend or bottom-out. It’s the sort of touch that shows TranzX weren’t phoning it in on the design. Top to bottom, it seems stout and sleek. Got me excited to ride it.

Riding it

I haven’t tried the Magura Veyron V3, but I’ll always remember trying the V1. Its reaction time was so slow, that I had pretty much given up on wireless droppers. That’s why the Reverb AXS seemed so magical. It truly is instant. Now, I have no way to perfectly measure if the Reverb’s signal moves any faster than the EDP01’s, but the fact that I’m not sure means that the EDP01’s signal moves fast enough. I think the only reason I doubted it was its louder audible “ZZZT—ZZZT.” Maybe my brain was able to clock a dropper’s noise more accurately than a dropper’s motion because it’s coming through my ears, not my legs. Like, it may not sound instant, but when you’re actually using it, it feels instant.

And I really tried to push the limits. We all have a lot of muscle memory after using dropper posts for many, many years now. It was only when I purposefully ignored that muscle memory that I found I could be quicker than the signal. Like, if I unweighted or re-weighted immediately after fully compressing or extending, it’d maybe give back 10 mm before it locked. So, it’s not impossible to get tripped up by the delay. But in my experience, it just wasn’t happening.

Unfortunately, that’s not the only “delay” that a dropper post can suffer from. The actual return speed on the EDP01 is relatively slow. I ran it at max pressure, and it still felt lethargic, especially after I was just spoiled by a brand-spanking-new OneUp V3, and especially when the Los Angeles winter threw some oppressive sub-50-degree temperatures at us. To be clear, the slowness issue was limited to extensions, and only from at or around full compression. There was never any sluggishness dropping the EDP01 down, and no noticeable breakaway thud when setting it in motion. And impressively, it was quick when returning from drops of just a few inches. This is often a problem on many posts because the air chamber isn’t as “charged” that near to full extension. But returns from the bottom floor were at a nagging fraction-of-a-second disadvantage compared to the OneUp, PNW and Reverb AXS posts in active service on my personal bikes. I found myself having to wait a beat before feeling it top out, letting go, and sitting down.

This is an interesting thing to pick apart now that we’re about twenty years into the modern dropper post’s evolution. There used to be such a thing as “too fast.” It’s why hydraulically-actuated Reverbs have a speed adjustment. Using one of those non-wireless Reverbs on my wife’s bike as a reference, setting its return-speed adjustment halfway between turtle and hare got me about the same speed as the EDP01. And even today, there are still plenty of cable-actuated posts on the market that I find frustratingly slow.

I happen to be testing a YT right now that specs their very recently updated Postman OEM dropper, and I think they pumped a bit too much molasses in the cartridge. A Bontrager OEM post I rode in 2022 was similarly sluggish. Both of these posts move slower than the EDP01, even though I’ve just spent two paragraphs complaining about it. So, it’s not unacceptable. It’s just not fast. If you know you’ve got a low tolerance for anything but the quickest-moving posts, you may be better off keeping your cable. I had been on that team for years. But after putting in more time on the EDP01 than I have any other wireless dropper, I started noticing all the perks that they offer.

So, electronic shifting is nice when you’re shifting. Duh. I guess what I mean is that, when you’re spending a lot of time going between gears on undulating terrain, removing the physical effort of cable-actuated shifting has a surprisingly significant impact. Shifting becomes almost telekinetic. It’s why I like powerful brakes. In my world, though, there is not a whole lot of undulating terrain. I’m going up for a long time, then down for a long time. Sure, electronic shifting is still nice, but I think an electronic dropper is nicer. While descending, I raise and lower my post more often than I shift. Even though the pedal-y bits are short, it still saves energy to pop up my seat, pump two cranks with whatever mid-cassette gear I’m in, and drop it back down.

Maybe that’s why I was able to live with the slow return. Sure, it wouldn’t always reach full height before I needed to get to business. But in that scenario, I didn’t need full height. These are high-speed technical sections that just happen to benefit from a little push. That’s not to say I’m letting TranzX off the hook. The Reverb AXS is faster. And to me, faster is better. But the Reverb was never gonna win me over because I could never abide its 170-millimeter limit. That’s bound to change someday, I just have no idea when. In the meantime, the only electronic posts available in modern lengths are the KS and this. But this is $200 cheaper than the KS, and $361 cheaper than the Reverb AXS.

Living with it

“Remember to charge your seatpost” is a phrase that is slowly becoming less and less meme-able. It is becoming a fact of life for increasingly more riders. And it’s particularly important on the EDP01 for one quirky reason. That time I managed to drain the battery, it didn’t actually stop working all at once. I got a warning with a few intermittent unresponsive triggers. In a way, that can be nice. It may give you the ability to put the post in the best position to get you home. But I warn you: Do not push your luck. I did, and an odd thing happened. The last time I actuated the trigger, the post only had enough energy to open the shutter, not to close it. So, instead of my post being locked up or down, it was just “loose.” Not sure about KS or Magura, but RockShox has a measure in the firmware to prevent this. Point is: Remember to charge your seatpost.

Speaking of firmware, updates will occasionally be available for electronic components like the EDP01. TranzX could someday even offer a fix for the predicament I got myself into when the battery died. The process can be done with a smartphone app … but I wasn’t able to try it. My poor old iPhone 7 can’t run IOS16, the minimum requirement for the “nRF Connect” app. From what I can tell reading the tutorial, the firmware update is less intuitive than AXS. A lot of technical-sounding steps, and some removing of batteries and holding of buttons. It’s not something you’ll run into often, and if you’re like most of us, not something you’ll do right away. But as with all technology, you’re probably better off if you do it.

As for other maintenance, pulling the EDP01 apart for cleaning is similar to most other posts. Except, you don’t have to futz with a cable. Just pull out the post, remove the air cap and lock ring, unscrew the dust wiper at the top, and slide it apart. Sort of a bummer that there’s no internal travel limiter like you’re seeing on more and more posts these days, but it’s otherwise pretty normal in there. Even the cartridge is fundamentally traditional. With the post disassembled, it can be released by a couple threaded pins at the top, though hopefully you won’t have to do that for a while. If you do, the EDP01 has a two-year warranty, which is thankfully becoming more common in the dropper world. I plan on coming back with a long-term review once I’ve got a few hundred thousand feet of climbing and descending on the EDP01, and plan on running it well beyond that.

And during that time, I’ll breathe a little easier in several little ways. I’ll never have to make sure there’s a little slack in the housing if I need to raise my saddle, or make sure there’s a lot of slack so I can clamp my bike in my repair stand. I’ll never have to go through the clumsy process of replacing an internally-routed dropper cable, eyeballing the length while removing the lever from the bar so the housing can surface from the seat tube. I’ll never have to disconnect it if I remove it for shipping or service. The housing will never get yanked out of its socket if my bike tries to do a barspin during a forced dismount. Again, the EDP01 is not perfect, but there are a lot of upsides to wireless droppers that, for some reason, get overshadowed by the pointless quest for a cleaner cockpit. If you get a chance to ride one long enough, vanity will slip further and further down your reasons for wanting one. The performance and livability benefits are a much bigger deal than just having one less cable in front of your handlebars. Unless, of course, you’ve got thru-headset routing.