TURNON COMPONENTS BUNKER DROPPER POST REVIEW

Words by Travis Reill  |  Photos by Drew Rohde

When considering which mountain bike or mountain biking components to purchase, there’s a choice between sticking with a known brand or branching out and trying something new. With a known brand, you are purchasing a reputation, which is usually accompanied by quality and performance you’ve come to trust. The pull to new technologies or ideas can draw you to stepping out of the norm and trying a component from an unknown brand.

Turnon Components and their promise of a fully sealed, 400-hour maintenance cycle dropper post was that “new” for us. While I’m yet to get close to the 3-year recommended service interval, I spent a lot of time using Turnon’s Bunker dropper post and lever. Read on to see if rolling the dice on a new brand was a risk worth taking.

ABOUT THE TURNON COMPONENTS BUNKER DROPPER POST AND LEVER

There are quite a few highlights to point out about the Turnon Components Bunker dropper post and dropper lever. Perhaps at the top of the list is the 400-hour – or roughly 3-year – service interval that Turnon recommends for the Bunker dropper. Anytime a company is figuring out ways to beef up a product, making it work for a more extended period will get our attention.

One aspect that pushes the Bunker’s life is that it is a fully sealed dropper post. Dropper posts typically have two holes on the bottom, allowing air to exit the chamber as the post is compressed. Turnon claims that things you don’t want leaving the dropper post can also exit with this air, such as grease. While a dropper post is relatively protected inside the seat tube, moisture and debris can be pulled back into the post when extended. Turnon uses a dual air chamber system to replace these holes, fully sealing the bottom of the post. At the top, Turnon uses what they call the “best dust cover” available for a dropper post, while remaining low-friction. Ultimately, this is why Turnon Components can call their dropper waterproof, with several videos on their YouTube channel showing the Bunker working in some antifreeze-looking solution.

The Bunker may be the most adjustable dropper post available. With the Bunker dropper post, you can essentially have any 5mm size increment from 125mm of travel to 190mm. They do this by allowing their two longest travel droppers—160mm and 190mm—to be adjusted down in 5mm increments. While all that adjustability is excellent, longer-legged riders may find the Bunker and Turnon Components limiting, as the longest travel dropper they make is only 190mm. As we see more and more bikes designed around very straight seat tubes that now fit droppers up to 240mm, Turnon could be left behind by stopping at 190mm.

Along with travel limitations, Turnon also only makes the bunker in 30.9 and 31.6 diameters. While there is an argument for those seat tube sizes being the most popular, my Stumpjumper Evo needed a 34.9 diameter, causing me to have to use a shim. This wasn’t necessarily an issue as I’ve used the shim for other dropper posts, but someone looking to purchase a new one will likely want one that fits without having to use a shim.

Turnon Components also sent their Bunker lever to accompany the Bunker post. The lever is solid, looks good, and is built with a quality Igus bushing. It also has quite a bit of adjustability, with 9mm of movement left and right, 4.5mm of movement up and down, and can be set at an angle. Honestly, there isn’t much more to report about the Bunker lever. I got it in the perfect position, and it worked as it should.

THE DIRT

I was excited to test a dropper post with 160mm of travel. I’m riding medium to large frames, and I find those sizes typically spec’d with 150mm or 170-5mm droppers, respectively. For the most part, 150mm on a dropper post can be too short. I’ve also had the experience a handful of times where I tried a 170mm dropper, only to find it was too long for me or frame insertion was an issue. So I hoped that Turnon’s 160mm Bunker would be the sweet spot for travel.

However, I found this wasn’t necessarily the case, as I couldn’t insert the Bunker into my seat tube as much as the 150mm droppers I’d been using. This was because the Bunker has a longer insertion depth than many other dropper posts—even dropper posts with longer travel numbers. For comparison, PNW’s Loam Dropper has an insertion measurement of 260mm for 170mm of travel. OneUp Components’ new V3 dropper at 180mm of travel has an insertion length of 270mm. The Turnon Components Bunker dropper has an insertion length of 274.4mm for the 160mm travel dropper I had on test. If you opt for the 190mm travel Bunker, you’re looking at a 312.4mm insertion length, 8mm longer than a 210mm travel OneUp V3.

While I was able to get the 160mm travel Bunker dropper to work on my Stumpy Evo, I imagine a longer travel Bunker may not have worked due to the insertion length. Yes, I could ultimately point the finger at the Stumpy’s frame design, but the long insertion may be a deal breaker for others, regardless of their frame. My guess for the long insertion length would be the addition of the second air chamber, which is claimed to help prolong the life of the Bunker and make that standout 400-hour service interval. So, would you rather have shorter service intervals with shorter insertion lengths and longer travel, or a post lasting three years?

The most significant issue I had with Turnon’s Bunker dropper was, unfortunately, a deal breaker. From my first ride using the Bunker dropper, the post struggled to stay put in my seat tube. Initially, I assumed I didn’t tighten the collar to the correct spec. However, after ensuring the collar was tightened to the spec’d 6.2 Nm, the Bunker continued slipping down on me. I over-tightened the collar to 7 Nm, and the issue persisted. I next wanted to try some assembly paste in hopes that adding a little grit would hold the post in place, but the Bunker moved so much on my ride that I ended up scoring it with my multitool. This helped, but I even had some movement after that.

We measured the Bunker’s diameter, wondering if it was just a tad too small. The claimed “31.6” wasn’t wrong, with our digital caliper giving a more precise measurement of 31.52mm. Several other 31.6 seat posts in the office gave a similar measurement—either 31.52 or 31.53. These posts had no slipping issues on the bikes they were on, and other posts I’ve used – including the one I’m currently riding – haven’t slipped in the seat tube of my Stumpy.

However, after some more testing, it seems that the shim was the issue. After switching the Bunker over to a different bike—with a 31.6-diameter seat post—the Bunker stayed put perfectly. Despite other 31.6 droppers working fine with the shim in my Stumpjumper, the Bunker didn’t get along with it. That bike also had a bit longer of a seat tube, helping to alleviate some of the long insertion issues.

My 160mm Bunker dropper/lever combo will set a customer back $308. Regarding dropper post-actuating performance, I think the Bunker dropper sits at an okay price. Aside from slipping in the seat tube, I had no other issues with the Bunker and felt like it was a solid-performing dropper post. However, other brands offer more travel and allow deeper insertion for a cheaper or equivalent price.

The Wolf’s Last Word

Despite the Turnon Bunker being limited to its 190mm travel, it is awesome to see a post with so much adjustability in the travel range it does have. Finding the right bike—a longer seat tube with a 31.6 diameter—was important, but once we got the Turnon Bunker on that bike, it performed great. However, going back to the dilemma I introduced this review with: When it comes to trying something new or sticking with what I know, in this case, I’ll go with the latter. While it is cool to see a company like Turnon pushing R&D on a product as important as a dropper post, ultimately, too many sacrifices were made to have this compete with the industry’s cornerstones.

Price:
$269 – Bunker Seatpost 160mm
$39 – Bunker Remote

Website: Turnoncomponents.com