The Turnon Bunker features a patented dual-air-chamber system and 190 mm of travel. With this dropper post, the Taiwanese manufacturer aims to make a statement. But does it deliver? And how does the Bunker fare in our dropper post comparison test?
Turnon Components focus exclusively on dropper posts, with the Bunker currently standing as the sole model in their lineup. What sets it apart from the competition is a unique feature: unlike other dropper posts, the Turnon Bunker relies on a dual-air-chamber system. This patented system is fully sealed, preventing dirt and moisture from entering. According to the manufacturer, it can last an impressive 400 hours without maintenance – a significant claim. Turnon even state that the dropper can function underwater. While we haven’t hit the local pool with our bikes yet, it might come in handy if that ever makes it onto our to-do list. Most other dropper posts in this test are only splash-proof, which is generally more than sufficient.
You can find an overview of this comparison test here: The best dropper post.
The Turnon Bunker Dropper Post is available in 30.9 mm and 31.6 mm diameters. However, if you have a 34.9 mm seat tube, you can buy an adapter sleeve either online or at your local bike shop to install the Turnon Bunker on your bike.
In terms of travel and pricing, the Bunker fits squarely into the budget category: 125 mm for € 238, 160 mm for € 254, and 190 mm for € 273, making it one of the most affordable dropper posts in the entire test field. However, with a maximum travel of 190 mm, it might not be an option for riders seeking maximum adjustability.
On request, the dropper can be pre-configured with reduced travel via the Turnon website, allowing adjustment from 125 mm to 190 mm in 5 mm increments. For DIY adjustments, you’ll need to disassemble the post and purchase the appropriate spacer kit separately. While this takes some time to install, the instructional video on Turnon’s website makes the process straightforward – and you don’t require any special tools either.
Weighing just 653 g, the Turnon Bunker is one of the lightest models in this test, and the stack height is very impressive too: at just 35 mm, it ranks among the lowest in the test field alongside the FOX Transfer Factory (also 35 mm) and the OneUp V3 (28 mm). Insertion depth is 312 mm, which puts it right in the middle of the test field. For comparison’s sake, the PNW Loam Dropper has a shorter insertion depth of 293 mm with 200 mm of travel, while the (175 mm) FSA Flowtron has 322 mm.
Aesthetically, the Bunker’s blue collar seal stands out. According to the manufacturer, it enhances the system’s sealing, protects against UV radiation, and prevents material degradation, ensuring a longer service life – it’s almost like they’ve given the dropper its own sunscreen ;)
The dual-air-chamber system consists of an ambient pressure chamber and an individually adjustable chamber, separated by an oil bath. For proper setup, Turnon provide a simple formula to calculate the ideal pressure and extension speed for your body weight: rider weight (kg) × 3.6 = PSI. The pressure should remain between 200 and 420 PSI. Pro tip: Always hold the valve upright during inflation to avoid oil leaks.
As for serviceability, while we didn’t test the 400-hour maintenance claim, all necessary spare parts can be ordered directly from the Turnon website. With the help of an instructional video, servicing the dropper at home is straightforward and hassle-free.
Installation of the Turnon Bunker is no different from the other droppers in this test. The saddle clamp relies on a classic two-bolt design from below, but be careful not to scratch the stanchion when using a multitool. Turnon’s 1By remote can be purchased separately for € 52. If you order the dropper and remote together, you get a small discount – nice!
The remote features an Igus bushing and a standard clamp, allowing for ergonomic integration into the cockpit. It’s also compatible with I-SPEC and Matchmaker adapters.
On the trail, the Turnon Bunker lives up to its name: it works reliably and moves up and down smoothly. However, the remote requires slightly more force to operate, which is linked to the internal system design.
If you overinflate the air chamber beyond the calculated value (as we did), the return speed becomes comparable to the FOX Transfer Factory. However, the counterforce increases significantly, making it harder to lower the dropper quickly – which is particularly challenging for light riders. Following Turnon’s recommended formula provides a balanced performance, with moderate extension speed and counterforce for dropping the saddle.
When you stop it halfway through its travel, the Turnon feels slightly spongy, almost like a lightly suspended seat post. This is a result of the cartridge system and is intentional, not a defect.
Conclusions about the Turnon Bunker dropper post
The Turnon Bunker Dropper Post impresses with its dual-air-chamber system, delivering reliable performance and solid functionality. The system requires slightly more force to operate, and lighter riders might struggle with the high counterforce when the air chamber is fully inflated. Additionally, the travel is limited to a maximum of 190 mm. Despite these drawbacks, the Bunker offers great value for money, boasting robust construction and a well-designed remote.
Tops
- Lightweight
- Long maintenance intervals
- Affordable
Flops
- Increased effort required to operate the remote
- Limited maximum travel
For more information, visit turnoncomponents.com
The test field
You can find an overview of this comparison test here: The best dropper post.
All dropper posts in test: BikeYoke REVIVE 3.0 | Crankbrothers Highline 11 | FOX Transfer Factory | FOX Transfer Neo Factory | FOX Transfer SL Factory | FSA Flowtron Dropper Post | Kind Shock LEV Circuit | LIMOTEC H1 | OneUp V3 | PNW Loam Dropper | RockShox Reverb AXS | SDG TELLIS V2 | TranzX EDP01 | Turnon Bunker | Wolf Tooth Resolve rev2
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Words: Robin Ulbrich Photos: Peter Walker
