Rockshox RS-1 inverted suspension fork review and actual weights

If you want to turn the mountain bike suspension world upside down, just create a fork that flips convention on its head, uses proprietary parts and price it into the unobtanium range.

That’s exactly what Rockshox has done with the RS-1. Introduced in April, they just finally became available about a month ago and I’ve been hammering it nonstop ever since. It combines Rockshox’s well regarded current damper technology with a massively stiff design and reasonably light weight, and, fortunately, it’s performance seems justify its rocking of the boat.

To put these first impressions into perspective, it’s important to clarify the brand’s goals for the RS-1. Being a cross country race item, weight was among them to be sure, but it wasn’t the biggest target. That would be performance, and it was tackled in two ways: Suspension tune and handling. The latter is the most noticeable difference by far. Not only does it set the bar for XC forks to come, it sets it really, really high. It’s easy to make a fork massively stiff by increasing stanchion diameter and beefing it up. To do it in a lightweight, XC race ready frame that feels like something much bigger is incredibly impressive. They also wanted to give it an race specific tune. Cross country competitors are notorious for damping the life out of their suspension in a misguided effort to make it more efficient, so Rockshox used this opportunity to tune the compression damping in a way that didn’t flop about under sprints but could still soak up trail chatter to maintain traction. When the fork can stay in contact with the ground without robbing the rider’s energy, that’s the real definition of efficiency, and their new Accelerator Damper seems to do just that.

Ready to race?


Rockshox RS-1 inverted suspension fork review and actual weights

Out of the box, the RS-1 with uncut steerer came in at 1690g. The expansion plug top cap is 37g. I cut 18g worth of steerer tube off to fit my size large Niner JET 9 RDO frame, yielding a ready-to-install weight of 1,709g (3.77lb).

Rockshox RS-1 inverted suspension fork review and actual weights

Starting at the top, the carbon upper is one piece from top of steerer all the way down through the body. Fortunately, it moves away from the alloy neck spacer found on the carbon SID forks.

Rockshox RS-1 inverted suspension fork review and actual weights

The XLoc Sprint hydraulic lockout hose enters on the non-drive side, where the damper is. Technically, there are no external compression adjustments, but the remote has their Floodgate control, letting you set the lockout’s breakaway threshold. Technically, that allows you to run the fork with a firm platform all the time, having it break into normal travel only when you hit something big. That said, Rockshox firmed up the lockout considerably compared to the SID, where such hacks worked much better. It takes a good bit more force to blow through the RS-1’s lockout. For more practical compression tuning, you can use their Bottomless Tokens to change air volume, which keeps movement plush at the top but allows four different ramp rates farther into the travel.

The plug on the drive side hides a bolt used to unfasten the air chamber, allowing that leg to be removed. The Solo Air’s Schrader air valve is on the bottom of the drive side.

Rockshox RS-1 inverted suspension fork review and actual weights

Rebound is on the non-drive side. Knob is sized well with large enough ridges to be turned easily with full finger gloves. Rebound damping range is wide, giving you plenty of control over its speed.

Rockshox RS-1 inverted suspension fork review and actual weights

Tire clearance is rather good, plenty for anything an XC racer is likely to use. This is what it looks like set at 100mm travel. Brake hose is routed through two solid, tool-free loops. They’re big, but they’re one of the best hose management systems I’ve used.

Rockshox RS-1 inverted suspension fork review and actual weights

Post mount brakes are sized for 160mm rotor minimum. Sag indicators for all three travel options printed on the stanchion. The RS-1 can be converted between 80, 100 and 120mm travel options.

Rockshox RS-1 inverted suspension fork review and actual weights

The Maxle Ultimate makes for very easy axle removal. Wheel removal is easy, too, but putting it back in takes a little more effort (keep reading). One big caveat about the Maxle’s lever placement: It must NOT be facing upward where it can contact the carbon uppers during full compression. There’s even a warning sticker on the lever to make sure you know this. Why? Because if you bottom it out and the carbon uppers nail the lever, it could damage the carbon and ruin your fork.

Rockshox RS-1 inverted suspension fork review and actual weights

The big question and single most controversial item about the RS-1 is the required Predictive Steering hub. Yes, it’s annoying to have to use new wheels or rebuild your current ones just to use a new fork, but there’s a good reason for it. Because the stanchions can twist and turn and compress independently of each other, the axle has extra stress in multiple directions. It not only needs to prevent rotation, but it needs to keep the stanchions sliding in unison.


A traditional axle wouldn’t be strong enough to prevent uneven movement, which would lead to potential hub bearing binding and friction, not to mention brake rotor rub. So, Rockshox kept the 15mm Maxle Ultimate, but created a solid 27mm secondary axle over it that slides all the way through the hub. Once clamped into the dropouts, it becomes a more solid system that lets the fork work as intended. And work it does.


SRAM Roam 50 alloy mountain bike wheels with Predictive Steering front hub review and actual weights

As part of the fork test, we received a set of SRAM Roam 50 wheels. The Roam 50 is their base level wheelset available with the Predictive Steering front hub. You can also get the hub separately, or use the DT Swiss option.

SRAM Roam 50 alloy mountain bike wheels with Predictive Steering front hub review and actual weights SRAM Roam 50 alloy mountain bike wheels with Predictive Steering front hub review and actual weights

Claimed widths are 25mm external/21mm internal, but these measured out at almost 26mm external at the very top of the bead. I didn’t get a chance to measure internal width before we mounted them up (SRAM’s MTB tech guys visited our office for the install and first rides and we were itchin’ to hit the trail). They use a full UST design with ample tire bead channels and a nice center groove. I mounted some Schwalbe Nobby Nic tires I’d been using on other wheels with Orange Seal sealant. They seated and inflated on the first try with a compressor.

SRAM Roam 50 alloy mountain bike wheels with Predictive Steering front hub review and actual weights

The rims have a very boxy shape with offset spoke placement. They’re built with alloy nipples, nylon lock rings and double butted steel spokes. There was little if any initial pinging during my first ride. The axles easily swap between all options. The rear hub is X0 level, but uses DT’s Star Ratchet system rather than a standard pawl-and-toothring engagement system. As such, it’s fairly quiet with very quick engagement.

SRAM Roam 50 alloy mountain bike wheels with Predictive Steering front hub review and actual weights

Claimed weight for the 29er Roam 50 wheelset is 1610g in it’s lightest configuration. Our test set had the tubeless rim tape preinstalled with an XD Driver Body and came in at 1,686g. The included valve stems added 14g.

As a true weight weenie, I would have loved to get the Rise carbon wheels. But, in all honesty, the Roam 50 setup has surprised me. They’re reasonably light and very stiff. The width is just right for aggressive XC and trail riding. They’ve been solid performers so far.



The most immediate thing I noticed was how much quicker the steering seemed. Most recently, I had been running the SID World Cup (carbon crown and steerer) and another 32mm stanchioned XC fork. Compared to those, the improvement in steering precision and reaction time is immediately apparent. Now I get what they mean by Predictive Steering – it’s not that the equipment can predict what you’re doing, but that it allows the rider to better predict what it’s going to do. And that’s immensely important when you’re pushing your skills and your equipment to the limit to shave seconds off a race course. You need to trust that your gear will take you where you’re aiming, and the RS-1 and Roam wheels do. That alone is worth the slight weight penalty over the SID.

Repetitive roots like these do nothing to impede the RS-1's forward momentum.
Repetitive roots like these do nothing to impede the RS-1’s forward momentum.

The second thing I noticed was how much stiffer it is fore/aft. Hit a section of roots or rocks and it just plows through. With traditional 32mm stanchion forks I’ve ridden in the same travel range, those same repetitive root hits would elicit a slight feeling of hesitation from the fork. They seemed to bog it down a bit, slowing forward motion as the legs bent backward. The RS-1 is simply unaffected by such things. It’s amazing to feel the difference, and it’s amazing how much faster it makes you feel through the gnarly, knotted, rutted chunk. Plus, it makes the whole front end of the bike feel more stable and connected.

The handling and the stiffness is the real story here, but the suspension is rather nice, too.

With the introduction of their closed bladder Charger Damper and Rapid Rebound, Rockshox made big improvements in their forks’  performance. The idea behind the combo is to keep the forks higher in the travel, where they’re smoother. It also keeps them ready for bigger hits and helps maintain traction. For the RS-1, they tweaked the tune to create the Accelerator Damper. Same concept, just with firmer compression damping and firmer lockout. Push on the handlebars in the showroom and it’s going to feel harder than a same-travel SID, Reba or Revelation.

On the trail, though, it opens up. It does an admirable job of erasing fine lines while resisting bobbing and brake dive. It’s taut, but it can still take a big hit. The Fast Black stanchion surface treatment is smooth and slick. Put it all together and you get a fork that lets you go faster in the corners, faster through the chunder and faster in the sprints.

The only complaint is the $1,865 asking price plus whatever wheel or hub costs you’ll incur to actually use it. It’ll be really interesting to see where the inverted design and technology go from here.

First impressions are fantastic. We’ll post a long term durability test when the time is right.


  1. Tyler – Thanks for this review. It will be interesting to hear how the tokens added to address the air volume change your riding experience.

  2. Quick clarification: “The axles easily swap between all options.” Is incorrect, no? The front hub is Predictive Steering ONLY AFAIK. It is not compatible with any other standard.

  3. Sounds like the fork, for the most part, is what it promised to be when reviled. A bit heavier than calmed though. What is the comparison to a Lefty? They both require a special hub but other than that, how do they stack up against each other.

  4. Thanks for the review. Any chance you could measure the A-C height? I’m hoping it is lower than the equivalent SID….

  5. I wonder why the sudden change to having the damper on the left leg and the spring on the right. All current RS forks (and pretty much everyone else) has the damper on the right. Anyone know?

  6. “The most immediate thing I noticed was how much quicker the steering seemed.”

    I don’t particularly care for subjective reviews. Try making this kind of statement in the F1 racing world.

    “Mr. Andretti, the car *seems* better handling.”

    “You’re fired. I want numbers, data, not your hunch, son.”

  7. “I don’t particularly care for subjective reviews”.
    Then go and read websites about industries that are resourced like F1.

  8. I think a better solution would be a Pike (I know min travel is 120mm) and lighter stiffer carbon rimmed wheels. The weight would be within 100g of the RS-1/Roam 50 setup reviewed.

  9. If your goal is to run the heaviest XC race fork on the planet, why not just ride a Pike? With the extra $900, you can certainly afford a light enough front hub to offset the 150g weight difference.

    Better chalk this one up as a Charlie Sheen sized win for Rock Shox.

  10. Rexated – 469mm by my best measurement (center of axle to top of crown). They offer two different offsets, too, so check what your current fork is if you like the handling and order appropriately.

    All – Regarding the Pike comparisons, keep in mind the compression damping is tuned differently here, more akin to XC / light trail and racing rather than all-mountain activity. The other thing to consider is putting lighter wheels on a big fork like the Pike to get the system weights similar could result in flexy wheels that wouldn’t yield the same system stiffness.

  11. If you need a specific hub anyways, it would have been great if they had gone for a 20mm axle, or 27 as they clame, and not using the current 15mm one. A big opportunity lost. For the rest, the systme makes sense when price is down to earth. If they keep the same speed of price evolution as they are doing with the xx1, this fork will be affordable in ten years, hopefully!!

  12. So, I’ve been riding the RS1 for about 130 miles. I have it in the 120mm variety. It’s rad, works, but is more of a “look at me” product that something revolutionary. It isn’t that light, not very plush, has way more stiction than any inverted fork I’ve ever felt. My Pike and Revelation forks feel much smoother. Then I’ll be honest, while this is the best inverted fork I’ve ridden and it does handle well, it doesn’t out handle a Revelation which is roughly the same weight. Pulling off a wheel in a race scenario is a PIA, see photo above with leg twisted.. Try putting the wheel back on in flustered race mode… Then to top it all off, the fork legs still twist like every inverted fork I’ve ever ridden (Shiver SC, Maverick). Grab a handful of front brake in a hard corner and you’ll know what I’m talking about. Again, I am enjoying the fork, love how it looks on my bike, but my next fork will likely be a Revelation.

  13. Tyler– LOL@the “lighter wheels” straw man argument. Same rim/spokes, different hub, please try to explain with a straight face how the RS1 is going to be stiffer than a Pike.

    And re: tune, it’s shims dawg, not magic. An XC-tuned Pike, or dialed SID, is an achievable goal. Although neither of the aforementioned is inverted, and inverted is the essence of progress…

  14. I’m excited. Not for this fork specifically, but for the potential benefits inverted forks will have in 5 years while hopefully by then be competitive weight and cost wise. Clearly inverted forks have some advantages. Maybe I should just run a Lefty.

  15. @Derp.

    Get back to us after you ride a 120mm Pike back to back with a RS-1.


    So much hatred towards a mere, physical thing that is outside of most people budget anyways.

    Ask yourself why?

  16. @mateo,
    (“Quick clarification: “The axles easily swap between all options.” Is incorrect, no? The front hub is Predictive Steering ONLY AFAIK. It is not compatible with any other standard.”)

    He is referring to the rear hub only.

  17. @Tino where, were, wear and ware are not interchangeable. Motorcycle axles and wheels have NOTHING in common with the mountain bike equivalent…

  18. Where is all the weight in this fork?
    Surely there are easier ways to stiffen the through axle?
    The price is a bit crazy.

  19. @Adam12. RS-1 and a lefty stack up in two main categories. First and most important to the ones that use or plan to use either of these forks- “HEY, look over here at my bike.” Second, both are really just an engineering study in function following form.

    anyone using either of these forks and are satisfied with the performance plus enjoy riding their bicycles, well that is really the most important thing. 🙂 🙂 🙂

  20. Yet another hub standard, with a heavier wheel. How about unsprung weight? A lighter wheel does a lot of good when it comes to a better working suspension.

    Motorcycle expierence says that a USD fork will allways be heavier and stiffer than a normal one. I’m curious to see whether this concept will work out for the XC-racers or that USD will move up to the all-mountain/enduro crowd.

  21. I was able to demo an RS1 for 60 miles of rough trail riding, and I must say that it performs very well. With that said, I still prefer the weight/cost savings of a Lefty, as there was no compromise in performance going with a more popular proprietary hub.

  22. One question I was hoping someone from Rock Shox or someone in that sort of field could answer is why not just design the fork with a 20mm thru-axel?

    Still want to try one though!

  23. I would be interested to see an article comparing the RS-1 to a carbon Lefty. I’ve got a C’dale trigger 29er and I’ve got to say I’m loving my supermax Lefty. (deleted)

  24. A lefty of this price is almost 500g lighter, that is one pound, and the lefty will be stiffer than this.

    They should have gone for either a current 20mm hub, or, if they wanted to go for a new hub standard as they have done, they could have gone for a 27 or 30mm new standard, and it would have fixed any of the issues of inverted forks…

    About the weight, boy, they will make it lighter in the next versions if they wanna make a xc racing product. it’s easy for them to make it lighter, this thing must be very overbuilt, specially the carbon part. I´m sure they just wanted to pay it safe in this first version, not to have any brakage reports. Also they can charge more the next versions, or attrack more people. Just the apple route; give as little as possible, in order to have a margin of improvement in the future… Contemporary capitalism…

  25. Ilikeicetea-You nailed 90% of the comments above. Quick, someone start a new thread on a forum somewhere so these people have something else to do 🙂

  26. @Rexated: It is not rocket science to actually measure and publish exact stiffness numbers. Some German magazines regularly run such test. Rock Shox most certainly has the numbers measured and compared to every other fork.

    But they do not have the balls to publish it. Just some vague claims.

    I bet it is not stiffer than Magura’s double arch design. Prove me wrong.

  27. ” It is not rocket science to actually measure and publish exact stiffness numbers”

    True. What you need is a dial type torque wrench and a bench where you bolt the fork. That easy – really.

    I sceptical of the usd forks in mountain biking. The two main advantages in dirt motorcycles, less axle overhang (i.e. the fork grabbing ruts) and longer seal life don’t really translate in to mtbs. There is a torque stiffness advantage, but this helps much more if you have double crown fork. With brake bridges that you can’t use on mx bikes you can get a conventional fork just as stiff.

  28. I am not trying or pretending to be a armchair engineer but…

    Why wouldn’t rockshox have deployed some sort of internal setup like the lefty, in that the lower stanchions would be unable to rotate left or right. This would prevent the need for a specialized hub to compensate for twist and lack of stiffness, plus-would automatically stiffen the fork, and wheel changes would be much easier without having to align the lowers to get the axle through.

    anyone else agree or am i missing something?

  29. I rode my buddies recently and d*mn it is really nice. The small bump compliance is awesome and the steering is like nothing I have felt before. Much stiffer than my Fox 34, Pike and Reba. Only thing I don’t like is putting the wheel in it or mounting to my fork mount roof rack. The left leg extends and is a PITA to push in.

  30. Seems like the ultimate set-up is this hub in a normal fork. All the stiffness gains of the hub interface with the additional stiffness of the stanchion arch. At least for now…

  31. ^ Agree with JBikes on using a better hub/fork interface.

    It seems like the USD fork design is not really needed, and not a good design or use for bikes. Everyone is making the moto argument of ‘well, it works great for motorcycles!’ Well, how many moto riders are taking their wheel off an on to put their moto on a roof rack, or in the back of a car? How many moto riders take their wheel of to fix a flat during a race? Zero.

    It doesn’t make sense.


  32. K11 nailed the cornerstone question.

    Does “Predictive Steering” have anything to do with “Sanction Rotation”? Would some % of allowable sanction rotation create a more racer XP setup?


  33. K11, I think if they designed the RS-1 around a square tube in a round hole they would need to use elements of the Cannondale Lefty patent box. Lefty is extremely well covered in terms of patents.
    the best solution would be a sort of two sided Lefty but that would likely mean RS would be tied to Cannondale for however long the lifecycle of this fork is.

    AS far as USD forks goes Lefty has proven for 15 years that there are tangible benefits to getting an USD right. RS-1 may be missing a trick with not having an anti-precession mechanism inside the fork (E.G. Lefty’s four sided flat sliders

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