Long Term Review: Fox’s Ultra Smooth D.O.S.S. Dropper Post

Fox Doss Droper PostPurchasing a dropper post is arguably the biggest single upgrade you can make to your mountain bike. The ability to drop and raise your saddle on the fly has had a bigger impact on our riding style than any pair of carbon wheels we’ve had the pleasure of testing.

Unfortunately, like all new technology, there have been growing pains. The early dropper posts we tested were sometimes rife with issues ranging from excessive side-to-side play or the need for frequent service intervals. So when Fox set about developing the D.O.S.S. (Drop On Steep Sh!t) Dropper Post, they wanted to address these failures. Their post has now been on the market for nearly two years and we’ve been hammering on two different posts for about that half time.

Have they succeed in building a maintenance free post? Drop past the break to find out….

Weight

Fox D.O.S.S. Weight  (4)

Without cables or lever, the dropper post weighed 538 grams.

Fox D.O.S.S. Weight  (2)

In the box you’ll find everything you need for set up, including a lengthy roll of cable housing (and cable). We didn’t end up using all of the included housing, so installed weight was probably shy of the 72 grams listed.

The gigantic lever, with speed holes, graced our scale at 57 grams.

Fox D.O.S.S. Weight  (1)

Weight weenies, avert your eyes. The total weight for this 5″ 31.6 diameter post was 667 grams or ~ 1.5 lbs. For comparison, the LH Thomson Dropper weighs 586 grams (a full 81 grams lighter), and the Crank Brothers Kronolog weighs 566 grams (which is nearly a quarter pound lighter.)

If you’re turned off by the weight, remember you can always reduce a “significant” amount by switching to lighter bolts and shift housing.

Tech

Fox DOSS Adjustments

The Fox post is available in two different sizes and lengths. Both the 30.9 and 31.6mm posts come in 100 and 125mm (4 & 5″) versions.

The dropper has three preset positions, which work in conjunction with Fox’s new suspension compression setting nomenclature – CTD. Climb mode is fully extended, Trail drops the saddle 40mm lower, and Descend mode is fully compressed.Fox D.O.S.S. Cutaway

It operates using a mixture of mechanical internals and a low pressure air system. Inside, eight stainless steel balls drop along three different length grooves to each of the preset positions. The lever is actuated using standard shift housing and a derailleur cable, so replacement parts are available at any bike shop in the world. And you can manually actuate the post should you somehow destroy your cable lever while out on the trail.

Ergonomics

Fox DOSS Lever Actuated

On the bike, the Fox lever occupies roughly the same space as a shifter. On bikes set up with a 1x drivetrain, the under-the-bar position worked best, but the lever has provisions for being mounted above or below, and on the left or right side of the handlebar.

The dual lever design also makes it easy to find the middle trail position every-time. When you depress the larger silver paddle, the post compresses fully, but push down on the black paddle and the post only clicks down 40mm.

Fox Doss Lever Close Up Adjustments

Depending on positioning, the bolt which adjusts for/aft position rubbed on our brake lever.

In the parking lot, the lever feels stiff. Particularly if you’ve become spoiled by the smooth action of a hydraulic lever. Once you’re on the trail, the lever actuation feels just right. It doesn’t take too much force to depress and we’ve never accidentally dropped our post.

We’ve been suffering a drought in California over the past two years, so we’ve never had the opportunity to spend much time riding in the mud, but we do have some concerns about the degree to which the cable is exposed to dust and muck at the head of the lever. That said, in nearly a year of riding in some of the dustiest conditions ever, we haven’t had any issues.

On the Trail

Breezer Fox DOSS Dropper Cockpit

On the trail and in the stand, the Fox dropper post feels remarkably solid and well built. Over the course of a few seasons worth of hard riding, we haven’t encountered any of the major issues we have experienced with some other posts. In particular, despite crashing on a 20 foot double and bending a set of seat rails, the post did not develop any excessive side-to-side play. While you can grab the saddle and wiggle it a few millimeters, the play is barely discernible when seated.

Unlike a hyrdaulic post, the D.O.S.S. does not require any force to drop through it’s travel. This is one of the main reasons I favor mechanical droppers. Instead of approaching an obstacle (or beer stop) and having to stand up and bump down the post, you can hold the lever and drop down a few inches effortlessly. When you’re riding for extended periods at your cardiac limit, not having to expend that little extra bit of energy is a relief.

When bumping the post up and down through its travel, there is a satisfying mechanical click each time the post engages.  Hit the lever and the saddle is almost instantaneously out of your way. The return spring is just as fast, but doesn’t pack a punch, meaning your man (or woman) hood is safe. We did experiment with adding more and less air pressure in the post to try and adjust the return speed, but found the adjustments made little discernible difference.Fox DOSS Lever

While some riders will steer clear of this dropper because it has three preset positions, I quickly fell in love with the setup. We’ve had several test bikes through our stable with Reverb posts, but I never missed the fully variable positions. The 40mm drop into trail mode is perfect for all but the most spirited riding, and it’s nice knowing exactly how far the post will drop. While the dual lever designs allows you to click down into trail mode securely every time, it’s much easier to find and engage the over-sized silver paddle.

Our one niggling issue was a knocking noise that sometimes emanated from the post when hovering just over the saddle. We’d also like to see a future version with either stealth routing or side mounting on the lower shaft – ala KS LEV.

Overall, the buttery smooth operation of the DOSS post removed any doubts we had regarding the chunky lever. The posts we have in for review feel as solid today as they did when we installed them last year, which is what you should expect from something that retails for $340 USD. If you’re looking for a no nonsense dropper post that won’t leave you stranded, the Fox is well worth considering.

RideFox.com

Comments

alex - 02/19/14 - 10:07am

The remote lever needs to be bigger.

gee - 02/19/14 - 10:23am

So in short, it has only 125mm travel, heaviest on the market, cable attaches to the top of the post, it’s expensive.

Bottom of my list, definitely.

groghunter - 02/19/14 - 11:40am

Love mine. Didn’t think I’d like the remote as much as I do, thought I’d end up doing what lots of people have been doing, and modify a front shifter to run it, but having a dedicated lever for the middle position is game changer (coming from a Specialized command post.) That said, it’s quality doesn’t match the rest of the post, and if they released a revised model that was better made, and especially if it allowed matchmaker or i-spec integration, I’d buy it. I’m not a fan of their suspension, but this post has been awesome so far. @gee: it includes a cable guide that helps quite a bit with the cable loop, and if you think it’s the heaviest on the market, you should go look at the DSP.

patrik - 02/19/14 - 2:30pm

Hideous looking. Please get rid of that inner tube color, which matches not a single bike ever made. Even the uppers on forks are going black. It looks like the Gravity Dropper did in 2004.

What - 02/19/14 - 3:00pm

Gravity Dropper still is the lightest, easiest to maintain and usually goes trouble free for years before you need a $15 rebuild.

norcom - 02/19/14 - 3:50pm

Have a Gravity Dropper, two iKS and three DOSS posts. GravityDropper is bomb proof and is going strong after 3 years of use. Parts are readily available directly from GD.

BOTH KindShock posts failed on me. One after 2 years and one after 8 months. You can’t get parts from Kind Shock and a rebuild is almost 50% of a new post cost.

The FOX DOSS seems very reliable but all three are less than a year old so far. Definitely not going back to the hydraulic posts. They’re nice and quiet but they’re nowhere near reliable.

Joe - 02/19/14 - 3:52pm

I want to add a dropper to my Scott Scale 29er. It already has a fox fork with the 3 modes, but I dont think I would want the three modes for the post. Do you know if Fox has a lever that will activate both the fork and the post? If so, do you know if it is possible to adjust the action on the post to only drop in the descend mode?

Mattbyke - 02/19/14 - 4:18pm

Another vote for gravity dropper. Flawless performance. Always works. Good price, and 27.2 size. Job done.

pornitswhatlwouldratherbmaking - 02/19/14 - 4:56pm

needs a stealh option

DaveG - 02/19/14 - 6:45pm

“Unlike a hyrdaulic post, the D.O.S.S. does not require any force to drop through it’s travel.”

O rly?

norcom - 02/19/14 - 7:11pm

Joe,
You can’t activate the post and the fork with the same lever. Those are completely different types of levers and the way they work. The FOX shock levers only work with the rear shock and fork. The post lever is push and release where as the shock levers have three settings on them and then a release.

Jake - 02/20/14 - 6:01am

So, I guess the big question is Fox or Thomson???

nouseforaname - 02/20/14 - 12:31pm

after 2 years of hard use, mine still behaves flawlessly. i don’t miss infinite travel at all. cables are easier to replace than any other post, much easier than dealing with hydraulic.

by comparison, a lev on another bike of mine got sticky after 9 months, and now ks has had it for 2 months and i can’t get them on the phone or to respond to emails. and i had 3 reverbs that each died after about a month.

fox’s customer service is awesome, and their stuff just plain works all the time. it may not be the lightest, have the slimmest level or stealth routing. but it’s a far better deal and experience over than any other.

Charlie Best - 02/20/14 - 12:45pm

Every time I read “buttery smooth” in a bike related article it makes me want to smash something up.

Saris Mercanti - 02/20/14 - 3:01pm

@Jake

Whatever is cheaper? Don’t think you can go wrong with either!

norcom - 02/21/14 - 6:13pm

Just an FYI about the DOSS. There are NO SERVICEABLE PARTS AVAILABLE FOR IT! Fox will NOT sell you any parts for it! Since I have three of the DOSS posts (one accidentally bought too short) and is in 31.6, I wanted to convert it to 30.9 for another bike by replacing the tube. They said they weren’t sure if that would be possible but also that they didn’t sell it individually. They said that “since we haven’t released the rebuild instructions, we’re not selling any parts for it”.

The parts availability directly from the manufacturer was the only reason I’ve been going with FOX stuff. If they start to restrict parts access, I’m planning on going somewhere else.

Fodster - 02/24/14 - 11:19pm

Seriously?!?!?! Gee nailed it! Get over yourself Fox. RS, KS, X-fusion are on the top of our list for droppers…and RS and X-fusion are also ahead of Fox in the suspension dept too! Norcom also nailed it with service…Fox in general is a nightmare to get service parts from…and I hear there service turnaround is even worse…maybe because they wont let any other service centers work on their product! ridiculous

Fodster - 02/24/14 - 11:23pm

Nice Alex! They should just have went with the office chair lever and had it stick out all the way to the handle bar!

Gee and norcom nailed it! There are no positives other then the legendary name which is almost worthless to me.

sean - 05/27/14 - 6:24pm

unfortunately some of you guy (like fodster) are completely off.. who wants to f… around with their post every time they want to drop it and try to find the ideal position…!? that is complete nonsense, its like having a randomize button on your fork.. lets press it and see what it comes out at. soon more post will have fixed positions IMO

andyB - 06/22/14 - 12:33pm

we have been using the DOSS seat post for over a year with at least three rides p/week, the post has performed outstanding and never failed, still tight and no wobble front/ back or sideways… top class post

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