FOX's new 620 gram D.O.S.S. (
for 'Drop On Steep Shit') telescoping seat post features either 100 or 125mm of mechanically controlled travel, as well as a 40mm drop 'Trail' position for rolling or technical terrain that still requires pedalling. The D.O.S.S. is part of FOX's 'CTD ride dynamics system', which refers to three distinct phases of riding: Climb, Trail, and Descend, with the post's three height postions - full height, 40mm drop, and fully dropped - corresponding to the CTD acronym. FOX has designed an interesting dual lever remote, with the smaller paddle only offering access to the 40mm drop 'Trail' position, in an effort to make finding the middle setting easier on the trail. The post uses a standard shift cable to control its mechanical internals. Our 125mm drop test model features a minimum insertion to saddle rail clamp height of 290mm, and measures 190mm from maximum insertion (
bottom of the top cap) to the saddle rail clamp. Both numbers were measured with the post at full height.
The cable operated D.O.S.S. features mechanical internals and a low pressure air return spring, as well as a novel dual lever remote that simplifies finding the post's middle height position.
FOX D.O.S.S. details:
- Mechanical internals
- Air return spring (10 - 25psi to adjust return speed)
- Three postions: full height, 40mm drop, fully dropped (Climb, Trail, Descend)
- 100mm or 125mm of total drop
- Two-bolt saddle rail clamp
- 30.9mm or 31.6mm sizes
- 620 grams (post, lever, hardware, cable and housing)
- MSRP $439 USD
The Details Dual Lever RemoteThe D.O.S.S. is the first telescoping post on the market to utilize a dual lever remote setup, with the shorter lever restricted to activating the post's 40mm drop 'Trail' position, and the larger lever letting the user run through the post's entire stroke. Why would FOX go this route? If you've ever spent time on any of the numerous mechanically operated posts that feature a secondary, slightly dropped seat height postion, you know that it can sometimes be tricky to find that middle setting. Struggling to position the saddle correctly while in the heat of the moment is the last thing a rider needs when approaching a tricky section, and the D.O.S.S. looks to remedy this.
The larger, outboard paddle (silver) allows you to use the post's entire travel, including stopping at the 'Trail' position. The remote's smaller, inboard paddle (black) restricts movement to the 40mm drop 'Trail' postion.
Pushing the large silver lever allows you to stroke through the post's entire 125mm of drop, including stopping at the 'Trail' postion that is ideal for fast, rolling terrain where you want a bit of extra clearance, but still need to pedal. The inner black lever will only allow the seat post to drop to the 40mm 'Trail' setting, a system that should make searching for the middle position a thing of the past. The design allows the same remote to be mounted on either side of the bar, top or bottom, without having to swap out clamps, and it is also features three different fore and aft positions. The remote lever isn't nearly as trim as what some of the competition offers, but its ability to be mounted every which way on the handlebar should allow most riders to find an ergonomic setup they can get along with, and it also employs a hinged clamp for easy removal.
A view of the bottom of the remote shows the three fore/aft position options.
Ball Bearing InternalsThe D.O.S.S's internals are like nothing currently used within telescoping posts. Eight stainless steel ball bearings roll on three different length grooves - one for each of the three height options - that have been machined into the inner wall of the main tube. The bearings are captured at the bottom of the post's stanchion, with them being forced outward by a locking cam. In the locked positioned, the largest diameter of the cam pushes all of the balls out and secures them into the corresponding grooves.
The locking cam is the flanged component on the far left of the rod. Notice the machined, angled pockets that either push the bearings out or allow them to retract.
When pushing the short lever to move the post to the 'Trail' position, the locking cam moves halfway through its travel, with four pockets machined into it allowing four of the bearings to move out of the grooves and drop into the pockets. The four remaining bearings sit in a linear groove that correlates with the 'Climb' and 'Trail' positions, allowing the post to fully lower to the 'Descend' position when the larger lever is pushed. Releasing the lever allows the cam to force all eight of the balls to move out and lock into the groove. Pushing the larger lever lets all eight of the ball bearings move inward, letting the post stroke through the entire length of its travel. The D.O.S.S.'s mechanical internals mean that the post should still function if an air seal fails, or you manage to damage the cable or the remote, by manually moving the actuation arm on the side of the post's head.
The exploded view above gives you a look into the inner workings of the D.O.S.S. seat post, with the one piece forged upper tube at the top (unfinished and cut in two), and a cutaway of a fully assembled D.O.S.S. post at the bottom
Self Adjusting Steel KeysFour stainless steel keys act to keep the post's stanchion from rotating, with each one being forced outward by both the keyway cam and four ball bearings. The cam forces the bearings outward when the post is locked into position, pushing the steel keys out into four grooves machined into the inner wall of the tube. Pushing the remote lever to move the post up or down also shifts the keyway cam, allowing the keys to relax inwards and the post to go through its travel. The layout means that there is very little friction from the keys when the post is going up or down, simply because the keys have retracted when the lever is depressed. This, combined with the post actually rolling through its travel on the ball bearings, mean that it should move very freely when activated.
The keyway cam is actually an entirely different unit from the locking cam, and has been designed to have no free play. The system has also been designed to be self-adjusting, with the locking cam pushing the keys out further as either the grooves or the keys themselves wear over time.
Installation and Setup Setting up the D.O.S.S. post is a piece of cake. The two-bolt saddle clamp is easy to work with, and the remote's hinged clamp means that you don't have to remove any controls to install it. The remote can be configured to fit either above or below the bar, as well as on the left or right side, simply by loosening a single bolt. There is also a three position fore/aft adjustment that allows you to tune its position to best fit your hand. We initially began with the remote on the top of the bar, on the left side, but swapping the position is so easy we ended up changing it while on the trail. Because we're using SRAM's Grip Shift, we are able to run it underneath the left side, a setup that won't play nice with trigger shifters.
The actuation arm is positioned at the side of the post instead of the more common location at the rear, and can also be swapped from right to left simply by flipping the seat rail clamps by 180 degrees. This setup is not only less likely to be contaminated by spray thrown up from the rear tire, but also makes for smoother cable routing.
Our D.O.S.S. arrived with 25psi in the air return spring, which is the maximum recommended amount. It rebounds quite fast at this pressure, with a very audible top-out noise to let you know that it's at full extension. We dropped the pressure down to about 15psi, which enough to still have the D.O.S.S. rebound quickly, but in a more controlled manner. The top-out 'clunk' was still present, which we far prefer over completely silent action.
The post's side-mounted actuation not only makes for smoother cable routing, but also means that you don't have to tilt, or even remove, the saddle to access the clamping bolt. This small detail was greatly appreciated given that clamping the cable requires moving the saddle on nearly every other cable operated dropper post we've used. Adjusting cable tension on the D.O.S.S. is easy via the remote's barrel adjuster, with two full turns making a big difference in the post's action. Too little cable tension and we found that the post had trouble lowering past the 'Trail' postion, hanging up slightly before lowering further. Turning the barrel adjuster counterclockwise a few turns, adding cable tension, eliminated this. Too much tension resulted in the post knocking up and down slightly, or even moving on its own if tension is excessive. Interestingly, the D.O.S.S. has a small amount of vertical play to it even with the cable undone, something that we were never able to remove from the system.
PerformanceThe funky looking D.O.S.S. remote had many riders asking us what was going on, but we have to admit that the dual lever design has major merits on the trail. Pushing on the smaller, inboard lever left no question as to if the post would find the 'Trail' position - it will simply only drop to that height. Contrast this to other designs that have left us searching for their middle settings, even after many miles of getting used to them, and we can see why FOX went this route. The remote also proved to be quite resilient despite its vulnerable looking position when mounted above the handlebar - it shrugged off quite a few crashes, as well as us flipping the bike over to perform trail-side repairs. We have to eat some humble pie here because we originally took issue with the remote's design, but the dual lever setup makes complete sense in use. Having said that, its ergonomics are a bit strange, with the paddles sitting at a bit of an odd angle for us. We never really found a position that we were completely happy with, despite the three fore/aft positions to pick from.
Required lever effort is about on par with anything else on the market, although we'd say that the long paddles should help over come the friction of a contaminated cable. The effort does increase for either lever if the seat has your full body weight on it when when you push them, but it isn't enough to be a deal breaker in our books.
The D.O.S.S. is incredible smooth throughout its travel, moving up and down with what feels like zero resistance, and making other posts feel sticky and slow in comparison. This is down to its ball bearing internals - the stanchion actually rolls up and down - and the post's low return spring air pressure of between 10 and 25psi. The action is remarkably effortless, and has remained so throughout our time on it. The air spring feels very linear as well, with us never having trouble fully lowering the saddle during those split second moments when the front tire is rolling over the edge of a precipice. When the paddle is pushed to raise the saddle back up, it happens rather quickly. The D.O.S.S.'s undamped rebound stroke is very similar in speed to Specialized's Command Post, with it returning to full height with zero hesitation. We view this as a plus, with it coming back up quickly and consistently when needed. This is especially helpful when navigating tight climbs and descents, as the return speed and very audible top-out noise left us with no doubt that the saddle was at full height once again. Finding the 40mm drop 'Trail' position on the post's upstroke could be tricky, so we usually resorted to bringing the post to full height and then pushing the 'Trail' lever to lower it part way back down.
The comparisons between the D.O.S.S.'s set three positions and an infinitely adjustable post are inevitable, and there will no doubt be many riders who are happy with the post's fully dropped and 40mm drop 'Trail' positions, but we couldn't help but find ourselves wishing for more range from time to time. It could be that our technical local terrain made the 40mm drop middle setting feel a touch tall (
45 - 50mm seems like it would be ideal, but that's just us), or that we missed being able to drop the saddle only by 10 or 20mm for a steep, technical climb that had us spooked about high-siding off the edge of the trail, but we still prefer the ability to set our saddle height
exactly where we want it.
The ambidextrous remote can also be mounted above or below the bar, with us far preferring the latter option. Keep in mind that trigger shifters would keep you from mounting it below the bar, though.
When FOX debuted the D.O.S.S., many riders showed their surprise that it didn't feature a stationary actuation point on the lower tube. While we admit that we also questioned the positioning on the seat post's head (
after all, why not eliminate one of the biggest hassles concerning dropper posts?), we were amazed to find that the location on the side of the post's head made a huge difference when it came to cable management. Yes, there is still a loop of surplus cable when the D.O.S.S. is lowered but it seemed to be far easier to deal with, staying off to the side of the bike instead of looping straight out the back to buzz on the rear tire. We also commend FOX for employing a two-bolt saddle rail clamp that is immune to tilting, regardless of how hard you come down on the back of the saddle. Sure, a single-bolt, clamshell design might be a touch lighter, but a two-bolt setup is really the only way to go.
The D.O.S.S. lets riders choose from a fully extended 'Climb' position, a 40mm drop 'Trail' position, and a fully dropped 'Descend' height.
Issues The D.O.S.S. proved to function very well on the trail, but the FOX dropper has a few quirks that we'd like to see addressed before we'd call it ideal. Our chief gripe concerns the small amount of vertical free play in the post at each of the three positions. While the play really only boils down to one, maybe two, millimeters, the knocking noise emanating from the movement turned out to be very annoying. It never got worse from new, but we found it to be disconcerting when we were concentrating on the trail ahead of us.
Our only other issue centers on the rather sizeable remote unit that, while fitting nicely between the other controls on the bar, is about as far from integrated as possible. When mounted atop the bar, it sits much higher than any of the other controls, not to mention that flipping your bike over to repair a flat will see it resting directly on the ground. It is much more incognito when mounted under the bar, though, which is where we preferred to attach it. Besides the questionable aesthetics, the remotes ergonomics are a touch off. The levers felt to be at a bit of an odd angle for our hands, with us consistently wishing for some type of rotation adjustment on the remote head that would keep us from having to reach so far with our average sized thumbs.
Pinkbike's take: | Where does the D.O.S.S. sit in the dropper post hierarchy? Does it dethrone the Reverb for top honours? There is no doubting that the FOX post is a top quality unit - just look at its Swiss watch-like internals - but the post's odd rattle and slightly-off remote ergos detract from its great action. Having said that, the novel dual lever setup scores it major points, though, with it eliminating having to hunt for that middle seat height, and its incredibly smooth travel does make all other dropper posts feel as if they've left underwater for a few weeks. If FOX can remedy the two points of discord mentioned above, we'd have to say that there would be a new boss in town. - Mike levy |
www.ridefox.com
I have a Specialized Command post, and have had no problems with it. It works great, has 0 play at the saddle, and the mechanical mechanism (similar to Fox's) is more reliable and lighter weight than the hydraulic posts. the Specialized has 3 positions like the Fox, and that's all I need. I use the intermediate setting for flat technical sections, the down position for downhill, and the up position for everything else. I can't think of any situations where I'd need something other than those options. It's too difficult to pedal below the intermediate position, and if you don't need to pedal, why not drop it all the way?
I would prefer if it had the cable clamp at the bottom like the Reverb, but I don't really notice the extra cable while I'm riding. My only complaint is that the lever design kinda sucks, and bruised my knee pretty badly when I hit it during a crash (this might be fixed in the newer model, lot's of people complained about it).
I just hope more options in the market will start to bring prices and weights down, because I'd love to get posts for my DH and XC bikes in addition to my trail bike, but they are too expensive to justify for DH and too heavy for XC.
www.pinkbike.com/news/First-look-2013-KS-Suspension-seatposts.html
I think its a little big saying Reverb is number 1 when you haven't reviewed the other contender for the top step.
LEV's been out for sometime now ?
and for the more capable human.. finding middle height on your dropper post aint that hard .. (if your not retarded !! )
1" less drop than the KS
$440 US sticker price
Cable loop to seat clamp
Ridiculous remote lever
_________________________
All adds up to: WTF. Fox, you're doing it wrong.
I still like my 36 Float, but after all this time I expected more. Biggest let-down since Matrix Revolutions.
and the new lev stays under the 245pounds aswell..
-One more thing, I've heard it sometimes has issues holding the seat in place. Anyone any thoughts on that?
As for this post, it looks shit compared to the reverb. If Fox release a mechanical disc brake and say it's as good as hydraulic, are you going to believe them? Fox Rockshox
Gumbly (mini-fingers-for-trail-setting-button) *twin paddle actuator*? Happy days fitting the remote to a bike with trigger shifters, if you wanna run it under the bars - Happy days if you run the remote above the bars if you need to flip your bike upside down on the trail etc....
Reverb = Infinate adjust, easy install for novice (with correct tools and watching online instructions), easy to bleed, no cable stretch, no cable contamination, easy-too-bleed, did I mention INFINATE ADJUST !!!!
Fox D.O.S.S. = FAIL (admittedly a rare one)
Not to sure of the prices at your LBS, but I picked up a Reverb aftermarket for ~ AU$350 !!! (Including full bleed kit) Thats a lot cheaper than $4xx for a mechanical, cable mech cluker .... If that is Fox's best effort at a dropper then they should give themselves an upper cut !!!
I didn't have a "man that's cool" moment reading the review. Just hope it doesn't sell "like mad" because that will have other manufactures thinking about their pricing. I saw a CTD Fox ad and with a shock, post and fork, it would set you back around $1500 to run that. And that's the basic stuff!! Don't understand why they sell the "low tier" forks for $600. It's not special or even new. Look at what it is, it's been around for 10 years!! Rock Shox Sektor has more adjustment for about $200 less and that's not even the low end. Guess Fox wants to be the Gucci of mtb...
So, probably around $600 with Kashima then?
f that fox price!
There is one good point to this post...being mechanical instead of hydraulic. Far more simple and fewer things to go wrong, and easier to adjust and maintain, and cheaper to maintain..quite a few things good about it actually..
Cloverleaf I understand your point about the travel. I've only recently bought the Verb and I literally haven't been on it yet so I shouldn't even be comparing the two What TLC could you mean for the Cable system?? Surely none in comparision to the hydraulics of the Verb..
Still prefer the look of the Verb at the end of the day, again thats subjective...
My point continues in my later posts, whereby the ideal solution is to have a mechanical and hydrualic operation. Even futhermore a memory adjustment... This could be achieved with what I believe you're saying is the mechanical post and the Hydraulic post combined.
One more point, surely by making the post sit (Some cases forced if you're puching down on the saddle hard) into holes etc, it'll soon wear out and produce a loose fit.
I want i-beam compatibility in a dropper post. No one really does it yet. That said, I'll prob never justify the cost and stick with my "regular" SDG i-beam setup. These prices have got to come down before that changes. And I'm not looking to argue about tooling and engineering costs in relation to retail prices.
Besides there isn't anything like "comfiest saddle", everybody has a different bone structure and as such everyone needs a different saddle, saddle X might be the comfiest saddle for subject Y but that doesn't mean that it's for subject Z.
I have no problem riding 50 or 70km with my i-beam saddles from Kore, surprisingly the one with less foam/thinner is better for me.
Yeah that was what i thought but these new designs feel no different than the traditional Xmm rails, i notice no less flex from my Kore on the KS Beam than the traditional rail on the 27.2 KS Supernatural.
As a Mechanic i have never seen a dropper post brought in for repair
more often than the reverb. Why use anything but a shift cable to run
to the post? hydraulic line? too fragile, hard to shorten etc.. makes no sense.
For tall riders it would be better to have 150 mm travel ( I still use the clamp for very steep terrain to lower the post fully)
Designing a protective item around the post lever (on the post itself). Or better, implement the actuation mechanism that is not raised or lowered with the post itself (Lev idea)
I have an impression that some posters did not live with the Reberb for more than 6 months, try and you will see what will happen.
Also the Reverb has a very flimsy creaking seat mounting mechanism that I could not do anything about. You have to struggle with the Reverb to appreciate DOSS design. Fox, make the price $250. Lots of people will follow. If my DOSS fails I will buy a Gravity Dropper and will stay with it forever.
imo, KS has the the best seatpost hands down @ a very reasonable price along with great customer service.
( though i have just bought a reverb and am awaiting delivery) and as for having a Kashima coat on the DOSS, i really hope that was said to be sarcastic at the price.
this reverb will be my 4th seat post having initially had one of the original infinite adjust KS ones, then have had 2 spesh command posts - still have the one - and now have ordered the reverb - so unlike some i would say that i've got experience of this type of product
looking at it without riding one the DOSS just seems to be a reengineered spesh command post with an overly complex release lever and a very high price. Though the in line seat is a good thing and i've had no reliability with the spesh so hopefully the DOSS should also be reliable but i cant help having my doubts about this particular fox product.
having gone from a infinite post, the ks, to the 3 position spesh posts until now i have prefered the 3 position but as my riding has got even more tech i'm finding that the 40 mm drop is not enough and the all way is too much, would agree that a better first drop would have been 45-55mm or even put a 4th drop in it and simplify the lever
Also my current frame really needs an in-line seat where as the spesh is set back about 25mm, hence why i'm giving the reverb a go- plus it was cheap
They are turning into Apple. They have some of the best products (apart from this dropper) but you pay the earth for them.
This makes everyone try to charge similar prices because they think they can.
This is the biggest problem I've seen and I think most other riders feel the same. The price of things is getting to be a joke. I'm embarrassed talking to non bike friends about how mush things cost.
I can get 2 tyres for my car for the same price as pair of double ply Maxxis
Higher labor and production costs. But it also means a super active R&D department, that is much more affective.
Triggers seem cool but where you going to mount this for people that have FD's ? Seems like it would be a big clutter in the cockpit or your just looking to target 2 groups , 1xXX setups or gripshift setups. Give me something that i cant justify spending over $400 on . Maybe we need Chris King or Hadley to produce a dropper seat post .
After having struggled with the reverb I found very pleasant the following:
Very easy to install the remote, no need to bleed anything
No stiction going up or down
Two observations:
It seems it would be easy for the water to enter the housing through the open section on the remote
The price should be more affordable for it to become more popular (it is cheaper to buy it online in the US, Canadian stores have exorbitant price tag on the item)
I don't see myself trying the reverb unless my CP blacklite gives out..... so I might not ever use one.
Trying to choose between the DOSS and Reverb, I am focusing on mental workload, i.e. how much thinking is needed during the physical action. This centers on making a choice between options vs. executing a control task (do action until condition).
Mike observes: "...you know that it can sometimes be tricky to find that middle setting. Struggling to position the saddle correctly while in the heat of the moment is the last thing a rider needs when approaching a tricky section" and "“Pushing on the smaller, inboard lever left no question as to if the post would find the 'Trail' position - it will simply only drop to that height. Contrast this to other designs that have left us searching for their middle settings, even after many miles of getting used to them..."
But then in closing he praises the Reverb: "...we still prefer the ability to set our saddle height exactly where we want it."
I'm sure that each has its merits. Ideally I would like to have both. But I have to choose one.
As an intermediate XC rider I'm thinking I want to perform a choice task (low, medium, high position) and let the seat post automatically deliver the position to me. With the Reverb, I would need to perform a control task: manipulating the controller until the seat "feels right".
Cloverleaf's comment seems spot on: "Because while I was holding the release lever down over rough terrain and trying to guage an approximate point at which to release the lever [with the Reverb] my mate was instead hitting it once and that was it [with the DOSS]."
Makes sense to me. Further thoughts on the "user interface" of these posts? Thanks again!
www.pinkbike.com/news/Specialized-Command-Post-Blacklite-Tested-2012.html
Just curious ... Even if Fox fix the angles of the bar-mech and the vert play in the post, won't the 'CTD' design limit the use compared to infinatly adjustable posts (Cable or Hydro)?
Infinite adjust ability
cable actuated
cable at bottom
one easy push lever/button - either right/left/under/over comparable
Affordable - under 200.00 sounds good
reliable/sturdy/and can take a beating - time and time/ year after year/over and over.
Friends have tried many similar products, one has been through 4 different posts (cb, ks, reverb) and all hydraulic models have caused grief, the reverb has needed several bleeds.
This DOSS looks over complicated in comparison and then there's the price.
Gravity dropper should drop their prices to around ÂŁ100 (I'm sure they could, simple mechanicals) then everyone would buy one.
who wants a mecanical droper for only 110 € ?
new ,with warranty , funcional and so far not a single problem.
www.ice-helmet.com/next/index.php?option=com_k2&view=itemlist&task=category&id=9:ice-lift-tige-de-selle-t%C3%A9lescopique&Itemid=91
That might just work.
Fox has really hit the novice rider/shit product nail on the head this year. CTD is stupid dumbed-down bullshit. Same with autosag. You don't know how to set up your suspension? buy a shock pump, ask a friend, and ride more. They should have made a rear shock to compete with the db air: more tuning options!!! that's all I ask. There are a few of us who know how to ride and set up our bikes.
People that actually RIDE i think enjoy and need to make adjustments to different various terrains , all this auto sag and auto this bullshit is for the birds.. I like adjustments and i like to fine tune for what i ride.. Sometimes im on flowy fast downhill stuff and sometimes im on steep rocky chunky gnar shit...
Fox is turning into cadillac lol
its made of gold!!!