Review
Turnon Components Bunker Dropper Post
OUCH! I grit my teeth, rolling away from one of the sharper G-outs on Mt. Seymour's Cambodia Trail, my crown jewels having been subjected to a possible vasectomy. 'Mom would be pissed', I thought, 'she still wants grandkids someday'. I need a longer dropper.
A few weeks later, a 190mm Turnon Components Bunker post arrived, with a slick blue seal, and a suave, 1by remote. After spending the summer with the Bunker, I have some thoughts on the bold claims this company makes.
Turnon Components Bunker Dropper Post
What makes the Bunker special? Most dropper posts have two holes at the bottom to allow air to bleed when the post is compressed, and then suck it up when the post is extended. Turnon claims this design is problematic for two reasons: when the post is compressed, grease can leak out of the holes and when the post is extended it can suck moisture and debris into the unit. They claim to have solved this issue with a dual air chamber design. The air circulated expelled during compression is held within the second air chamber, as opposed to escaping via holes at the bottom.
I've never had a post leak lubricant and the inside of my seat-tube always remains clean and dry. Turnon claims a 400 hour / 3 year service life. I seek to discover the trade-offs of this rather sensical, yet esoteric design.
Highlights
- Dual Air Chamber Design
- Waterproof (IP68)
- Adjustable Travel
- Rebuildable
- Self-bleeding
- Self-lubricating
- Quick actuation
I received a 190mm Bunker post in a 31.6mm, alongside a 31.6mm to 34.9mm shim for my Trek Slash. The post is available in 125mm, 160mm, and 190mm lengths. Travel is adjustable at 5mm or 10mm increments via kits that are sold separately. Additionally, Turnon sells replacement parts such as shafts, upper and lower tube kits, service kits, and seals.
Bunker 1-by remote
The remote worked. For me, a good remote has plenty of up, down, and angle adjustment, smooth action, short enough throw, and is small enough to stay out of the way. Size matters.
This remote has a quality CNC machined finished with smooth lever action and a short throw. Most noticeably, it has very light lever action, partially a result of the efficient cable routing of my Slash. When the cable was adjusted, 5mm of lever throw actuated the post. I've used remotes from Fox, Oneup, Bontrager, and Wolftooth and the Bunker remote felt the best due to the concave, textured face. Rotating around an Igus bushing, the bunker remote offers 9mm of x-axis and 4.5mm of y-axis adjustment, and it even moves along the y-axis. It is available in both black and silver.
Installation
If you've installed a dropper before, this process should be dead easy. I pushed the cylindrical actuator nut down to the end of the cable and hooked it into the metal loops at the bottom of the post. The bottom of the actuator is deep enough that the cable won't unhook when not under tension during the install process. With many other posts, especially those that rely on the cable head hooking onto the bottom of the actuator, I've put the post into the frame and tensioned the cable, only to push the lever and find out that the end of the cable unhooked while the post slid into the frame. Installation of the Bunker took 5 minutes in my garage without a stand. Suffice to say, it's straightforward.
My only concern with the cylinder head is that the clamping plate nut on the topside of the rails is cylindrical, and sits sideways into the top plate of the rail clamps. Threading in the saddle rail bolts caused some fuss when the nut kept falling. The lack of notches also made it difficult to align the nuts. The notched, vertical nuts on the OneUp V3 are easier to work with.
Putting it all together
After four months of riding, the Bunker is moving as smoothly as the day it was installed but I've only managed to put ~80 hours on the Bunker. I gave the barrel adjust a twist after the first few rides and lubed the seal head after two months out of caution.
The seal kept the shaft clean and lubricated, even during muddy rides. After the test period I removed the seal head and shaft again to reveal that it was clean underneath. Most of the grease was present, and no debris had penetrated. Turnon has good how-to videos and they sell small parts individually so you don't have to buy parts you don't need. The Bunker developed some side-to-side play during the break in period, but this is par for the course with most droppers I've ridden.
Due to my long legs, 150mm is a non starter, 170mm is the bare minimum, 190mm is great, 210mm is near perfect, and 240mm is approaching overkill. The Bunker is extremely adjustable, with 5mm or 10mm adjustment intervals. If you ask at the time of purchase, Turnon will adjust your travel out of the factory.
A consideration for smaller riders, or those without uninterrupted seat-tubes, is insertion length. Possibly because of the second air chamber, the Bunker has a longer insertion length, relative to travel, than most posts on the market. The 190mm Bunker is 8mm longer than a 210mm Oneup V3 (the post with the shortest insertion length).
So, who’s this thing for? Why buy this post? The Turnon Components Bunker offers a value-oriented, extremely durable (thus far), easy to service, dropper with smooth actuation and a well designed lever. If you prioritize parts availability, long service intervals, and reliable operation, and are not concerned by the longer insertion length or 190mm max travel, the Bunker is a worthy option.
Turnon Components Bunker Dropper Post and 1-by Dropper Lever // 291 USD
Height - 6'/183cm (mostly legs)
Weight - 155lbs/77kg
Inseam - 34"/86cm
Ape Index - The Original Slinky™
Age - 22
Bar Width - 780mm
Preferred Reach - 485-500mm
Comments
jhtopilko
1 month ago
Do you think the seal is as good as the one up v3? I have a v2.1 and have a 35" inseam and am considering the v3 currently in 240, I have a 210 now with 80mm of exposed post.
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Matt Cusanelli
1 month ago
Good question, while I haven’t spent significant time on the V3, I had a OneUp V2 on several bikes and never had seal issues. In that regard, they are both excellent. A 210 with 80mm exposed, how tall are you? What bike are you running? Feel free to check out our review of the OneUp V3 HERE
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BarryW
1 month ago
Looks like a decent dropper, I'm just not sure why I would want this over a OneUp or Wolftooth if I'm looking for a more 'premium' option.
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Matt Cusanelli
1 month ago
Fair play, without getting into the nuances, I see where you're coming from and in large part agree. With that said, the Turnon was running incredibly smooth after a season of riding, and it is cheaper than the Oneup (Turnon even sells the remote at a discount when you buy the post). It came with a cable and plenty of housing which saved a trip to the local bike shop as well. While I would probably favour the OneUp at present, I'm really happy to see worthy competition in the marketplace - I think it benefits us greatly as consumers to have more choice.
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Jotegir
1 month ago
So wolftooth is significantly more "premium" than oneup so I won't comment with regards to that one, I'm not sure the Bunker is going to be cross shopped with it. In Canada, the Resolve V2 is a $550 unit, the Oneup V3 is like $360, and this runs around $340 CAD, maybe it's a wash with oneup with shipping into Canada, I don't know.
The key difference I see in this is that the bunker seems to be fully rebuildable with minimal or affordable parts, not being a cartridge based post. A Oneup cartridge runs $115. If you're paying labour, it's probably better to just wait for a Oneup sale and buy a new post rather than paying for the cartridge and labour. That might count for something.
That said, 3 of my bikes are running oneup and that's not going to change anytime soon.
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Matt Cusanelli
1 month ago
Agreed, the offerings from Rockshox, Wolftooth, Fox, and BikeYoke really aren't in the same league. The Bunker didn't need special tools, all the parts are inexpensive, and the videos (similar to OneUp) means that if you're a home mechanic or can handle tools and have some time and patience, it can be done quite affordably. If any of my OneUps needed a cartridge and I wasn't able to do the work myself I'd be looking at a OneUp V2, which are on sale at present for in the realm of $240. There's also PNW to consider as they have the Range Dropper bundle at 275 CAD, which includes the remote. I do like the idea of something that is fully rebuildable from an ethical standpoint even if it is more cost effective to buy a new post when the cartridge needs to be done.
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XXX_er
1 month ago
Cartridge for my SDG Tellis lasted 2 yrs, replacement was I think 65$ with shipping and the rebuild takes about 5 minutes
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Matt Cusanelli
1 month ago
The Tellis is another great offering amidst a similar price point to OneUP, Turnon, and PNW droppers. I had a 180mm OneUp that was brand new, used it for two years, and another 210mm OneUp that was purchased used and lasted another 2+ years. Some of the cartridge concern goes out the window when you realize that a lot of us, from my observations, turnover bikes every 2-4 years predominantly. Of course there's outliers though.
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Lynx .
1 month ago
Decent looking post, the extra insertion depth I think will loose them quite a few sales, but then to counter that, the small parts availability and ease of service is fantastic. Still not sure if I'd go for this when I can get several posts under $200 USD.
Sadly another post to enter the market with no offset option, something I look for with all the stupid steep STA these days 9point8 seems to be the only option out there and the fact that the post can use either zero or 25mm offset is, IMHO a game changer and well worth the price. Haven't done it yet, but far as I understand they're also fully rebuildable.
Oh developed play should not be par for the course for droppers, not ones that might be considered premium, my 9point8 FallLine ran for 4 years before I stupidly decided to try a different grease that didn't mesh with the seals and it never developed any side to side or for/aft play, rock solid.
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Matt Cusanelli
1 month ago
Stepping outside of the full suspension realm especially, or looking at bikes with uninterrupted seat tubes, the extra insertion length may not affect some people. The Slash, having a very slack seat tube, didn't have me wanting any offset. It was a small amount of play, only noticed when the bike was in the work stand, not while riding - my experiences with most other droppers have bit of play after some riding time, but its hard to quantify play or to establish a baseline for sensitivity to play.
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Lynx .
1 month ago
75.6-76 degrees is a VERY slack seat tube angle, really? Holy shit man, do you only ride super steep, winch and plummet or do you do any rolling/flat and/or less steep climbing type rides? Anything over 74 degrees and there's not a chance to put any real power down, my knees hurt on anything not steep, I'd have to go to such an easy gear and spend my life hamstering up climbs almost walking speed, a ride would take forever.
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Matt Cusanelli
1 month ago
Those numbers you are citing are the effective st angle, not the seat tube angle. If you look at a side profile of a Gen 5 Slash you'll see how misleading citing the effective st angle is when it comes to its impact on riding position. Further, when manufacturers cite effective st angle they assume a certain seat height to measure from, which results those having a longer seat height than what they measured the effective st at to have a slacker st. With my seat extended, and at sag, the arbitrary 75.6-76 degrees effective et posted on the Slash geo chart does indeed feel 'very slack'.
With that said, I don't ride roling or flat terrain on my enduro bike, I have a gravel bike or a rigid flat bar bike for that stuff. When I'm on the full sus were either shuttling or climbing/hiking steeps followed by steep descents.
But then again, I have 22 year old knees and utilize my home gym to do some further knee bulletproofing on a weekly basis so I may just be immune, for now.
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Lynx .
1 month ago
Well, I did happen to look at them and I downloaded the full side on image and extrapolated out the seatpost extension (using the 170mm stock crank) to 810-830mm BB to top of saddle and measured the ESTA and I got 76*, which is just about what I run (32.25") at 6'2" with a 35.25" inseam, which to me is STEEP AF unless you only winch and plummet ride.
Would have to guess that maybe the bit sits heavy into the rear travel if it's feeling slacker, 'cause otherwise, no 75+ ESTA is not slack, except to the marketing guys and their BS.
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Jotegir
1 month ago
Gen 5 slashes run quite slack in reality on anybody running a decent amount of post extension on larges and XLs. Trek publishes actual STA at 66.6 in slack, which is... super slack, even for actual STA? Looking at how much our boy Matt is running on his large (given that's a 190mm post at extension), he falls into the "almost certainly slacker than what the chart says" camp, falling outside whatever arbitrary intersection of seat height and actual STA Trek picked for their chart to make eSTA.
Hey Matt, if you're interested you should see about getting one of those fair bicycle offset seat post heads in to test. I'm quite enjoying going a little bit steeper on my on-paper-75-but-in-XL-reality-less seat tube angle bike.
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Matt Cusanelli
1 month ago
As with you, almost every bike I ride has drastically more seat post extension than would've been calculated at the time of geo chart creation. At 6ft, but with long legs and a short torso, XL's are too big, but I can pretty but get away with running a 240mm dropper on every large I've swung my leg over, Slash included. I'm really intrigued about the Fair option, would certainly solve the problems I've encountered on my slash.
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Lynx .
1 month ago
So $160 USD to try and fix you're already expensive dropper :rolleyes:
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Andy Eunson
1 month ago
Fairbike sell offset post heads. I have a couple. One on my 78 sta bike and another on the wife’s bike. Expensive but well made. I think it’s a 2.7 cm offset. Forward or back. The only negative is that with the saddle further back and 180 drop, the tire will rub the saddle at full compression. A mullet would solve that, but on my bike 180 caused just little too much insertion depth with cable interference with the internal tube anyway so I deduced the travel to 170. https://www.fairbicycle.com/shop
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Matt Cusanelli
1 month ago
Thanks Andy! Might give this ago to offset the seat-tube angle on a hardtail - Pipedream Moxie Mx3 and Kona ESD that I've ridden in the past at 77.5 STA have been great once pitchforking up a climbtrail but too steep for the on-road crawl to the trail. If only this was adjustable on a slider of some sort.
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XXX_er
1 month ago
I think the last dropper I had a was a fox on a bike which I traded away but the fox & the SDG both went up/ down, I couldn't tell much difference and the rebuild was pretty cheap & painless so I don't know if there is much point in spending more moneY other than mayeb weight ?
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Sethimus
1 month ago
stopped after 190mm, is this a post for ants?
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