First things first. The new Fox 32 SC AX is basically a prototype product that they’re willing to sell you. It’s not for everyone. And it’s not for every bike.

The backstory: Several Fox employees wanted it, so they cut down their existing SC 32 fork’s air spring to just 40mm. The reaction among those riding it, and even those who just saw it, were so positive they knew they had to get it into the line for 2018. That meant modifying existing parts rather than designing all-new castings and parts. They’re calling it an “open project” and is likely a taste of things to come…

2018 Fox AX gravel bike suspension fork

The externals and internals are based on the existing 27.5” 32 SC XC fork. The only real difference is that the travel has been knocked down and they’ve tuned the air chamber for gravel…by adding spacers.

2018 Fox AX gravel bike suspension fork

The AX uses the FLOAT air spring and FIT4 sealed bladder damper with three position -Firm/Medium/Open- compression controls on top and low speed rebound on the bottom.

Normally it’s the Factory series with Kashima that gets the additional Open controls, but these get the new-to-aftermarket Performance Elite spec, which means top shelf tech with the black stanchions. (This trim level debuted on the new Fox 36 and will spread to more forks for 2018)

Firm has a generous blowoff so you won’t hurt your wrist if something surprises you, which is good because they think most people will keep it set there for most rides. The black center knob provides 22 additional fine tuning clicks in the Open mode. Run those small clicks all the way to the softest setting and it butts right up against what you’d get from Medium mode.

2018 Fox AX gravel bike suspension fork

The AX gets the new EVOL air spring design, which also debuted with the new 36 and will quickly make its way onto other 2018 Fox forks. Here, EVOL means a larger negative air chamber to make them more supple. Because Fox forks’ travel is based on the length of the shaft connecting the air piston to the bottom of the fork, changing the travel does not change air volume. But, with a 60% reduction, they needed to reduce the volume to “tune” the fork for the shorter travel. They did this with volume spacers.

Four come pre-installed, and it can run up to 8 spacers. Counterintuitively, you’re likely going to want to run MORE spacers than you would on a longer travel fork with a larger air chamber. Why? Because with only 40mm of travel, it’ll be much softer with fewer spacers and is more likely to bottom out, so you’d have to run higher air pressure, which would make it firmer overall and defeat the purpose.

By running more spacers, you can run lower pressure so it’s softer and more supple, taking up the little (gravel sized) bumps, and then it’ll ramp up harder to avoid a harsh bottom out.

So, proportionally, the negative air chamber is larger than what it’ll be on the regular 32, which helps make it more supple.

2018 Fox AX gravel bike suspension fork

Fox’s team suspension expert says you’ll want to start with about 30psi more air pressure than you’d run in the 100mm 32 SC XC. And he recommends starting sag at 15% since it’s going on something more like a road bike. Ultimately it’ll come down to personal preference, but those are the recommended starting points.

2018 Fox AX gravel bike suspension fork

SPEC HIGHLIGHTS

  • $819, only one model.
  • Available May 2017
  • 2.9lb claimed (w/ cut steerer tube)
  • 15×100 Kabolt tooled thru axle
  • Axle-to-crown: 427mm
  • Rake: 45mm
2018 Fox AX gravel bike suspension fork actual weight
1425g = 3.14lb on our scale, with uncut steerer

So, what does this mean for the future? If it’s well received, they’ll dedicate resources for a purpose-built gravel fork. Should you wait? It depends. One caveat with this particular design is that the crown might contact your down tube. The other is that it could change your head angle by up to 1.5º, so if your bike is already slack, this might make it too slack. The link at the bottom of this post is the micro-site Fox setup for the AX to help you determine if it’s a good fit for your bike.

A crown race spacer helps the knobs clear the downtube on some frames.

These issues -axle to crown, offset, etc.- would be addressed in a future model to improve the range of bikes it can fit. They’re already hacking it, doing things like putting a headset spacer on the crown race (makes it 0.5º slacker) to improve downtube clearance on smaller frame sizes, or simply grinding off a bit of the compression adjustment knob’s lever.

All this is to say if this the AX fits for your bike and riding style, go ahead and take advantage of it. If not, let them know if you’re interested. A gravel-specific fork, should the market want it, could take an additional two years to develop and test. It would likely see a lower drop on the crown, 12mm thru axle, shorter stanchions, thinner legs and a more streamlined appearance that would fit more frames and match the aesthetics better.

And if you already have a 32 SC XC fork, technically all you’d need to change is the Air Shaft to go from 100mm travel on the XC fork to 40mm travel on the AX fork. Parts would be a little more than $100. Unfortunately, because they’re making it on the 27.5″ wheel fork chassis, they don’t have the parts to turn a 29er SC XC fork into a short travel monster crosser, but hey, if there’s demand…

Stay tuned for a full ride report.

RideFox.com/AX

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18 COMMENTS

  1. nice experiment and will be better than “some kind of suspension fork but really, not”
    that said its too heavy, expensive, etc. for 40mm of travel (i get it – that’s why its an experiment, but still)

    I also strongly suspect that even if it was really light and cheap – a lot of people would still not buy it because “it looks like a mtb, not a road bike”

  2. Cannondale needs to bring back their Head Shok? Although that would suck since it’s below the head tube, thus changing your bike’s attitude under brake dive/compression. If one can get over their reputation, what Specialized is doing on their new Roubaix with that stem shock might be cool to see on a gravel grinder?

    • The dive issue is present for any suspension type that is in or below the head tube (like the Fox or Lauf).

      To an extent, dive is still an issue with the FutureShock on the new Roubaix as well. The rider will still experience a shift forward and down. The difference is the bike’s geometry is unchanged, where a normal fork like those above will steepen and the head tube, shorten wheelbase and drop at the BB.

      I am hoping/expecting the new version of the Diverge to feature a FutureShock. Hoping for that and room for 40+ tires on an updated model.

      • Yes, they need to drop the SCS rear end for sure.
        Also, I am hoping to see BSA threaded BB return (like some of their other recent models like the Enduro and Epic HT).

    • My guess is Trek will be re;easing a duo Isozone Boone and a new gravel bike with the same. The Boone has been spotted but nothing yet on the gravel version.

  3. Is it just me. Are bikes getting heavier? 15mm axles, dropper posts (which I agree are worth it but please can someone make a lightweight one.) + size tyres, Disc brakes on road bikes and now suspension forks on cross/gravel bikes. What is the first thing you do when your looking at a new bike in showroom? Pick it up to see how much it weighs! We need more weight weenies in the industry.

  4. Suspension on bikes makes sense and even on smooth pavement has been shown to be faster. That suspension isn’t the norm has more to due with tradition and the misguided belief that a few ounces of weight actually matter. I do get the people who recoil at suspension because it adds complexity and potential maintenance headaches.

    • Suspension can come from tyres though. If 650×50 won’t cut it I’d take a light MTB 29er over a drop bar bike with sus forks, personally. I rode a Slate for an afternoon and loved it but I prefer rigid forks and the right tyres for mixed use.
      Best bit about all this is the experimentation thats happening however .. no right answer to it all.

  5. RE: bring back headshock. Still riding a 2001 Cannondale disc F700 with headshock. switch between 26″ and 700c for commuting, and now riding gravel with it. Very versatile design even after all these years. Not sure why Dale discontinued HS. I like lefty, but HS allows me to use any wheels from my other bikes.

    • The Headshok was discontinued because bikes were moving to longer travel. Apparently if you go over 80mm of travel with that design, it starts to get iffy. But yeah, it would be great to see that design for applications like gravel bikes or short travel for road bikes. But- with XC bikes nowadays having a minimum of 100mm travel up front, road, gravel, and perhaps touring would be the only, and at that rather small, niches for the Headshok, making it rather unlikely that it would be proiftable for Cannondale to produce them. Heck, they seem to even be moving away from the Lefty, at least in the North American market. If they can’t/ don’t want to sell one unusual (but effective!) design, they probably won’t be able to sell two of them.

  6. I don’t see why you wouldn’t buy a Lauf over this? Similar price, far lighter, not needing regular service. I love my 29er Lauf and know its shortcomings for mountain biking and get why others wouldn’t like it. But for a gravel bike, it just makes way more sense than this thing with not much travel and lots of heft

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