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…
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.
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.
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.
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.
- $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
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.
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.