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Updated w/ New Photos: Prototype Fox Reverse Arch XC Suspension Fork?

Was Fox testing unreleased tech in plain sight?

Marathon XC UCI World Championships startPhoto via @CyclingWorlds
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This week, Scotland is hosting the best mountain bikers in the world as the 2023 UCI World Championships continue. With the top racers from each country toeing the line, there’s bound to be some of the best equipment in the world as well โ€“ including some prototypes.

We received an anonymous tip that a racer might be running what appeared to be a new fork from Fox that was all-black. There were no pictures provided, and even with a reporter on hand at the venue, the bike in question has proven to be elusive. So we set about combing the internet to see what we could come up with.

After some extensive digging, it seems that we found it on the front of a Canadian racer’s bike in the Marathon XC race. Both of the pictures we found don’t list the riders in it, but by the Canadian jersey and the color of the helmet, it appears to be that of Andrew L’Esperance who races for the Maxxis Factory Racing team on an Ibis Exie.

Screenshot from Instagram

What’s interesting here is that in all of the photos we’ve seen from the race, the Fox-sponsored riders are on the factory-orange forks with Kashima. Even Andrew posted a selfie before the race where you can see an orange Fox fork on the front of his Exie.

Yet, in photos of the race, he is one of the only Fox riders on a black fork. On Twitter, we found two photos of the race where you can just make out the fork on the front โ€“ one from the start of the race from @CyclingWorlds, and the other mid-race from @annew4287.

Zoom in far enough and we’re left with some Bigfoot-level graininess, but with the black fork next to another orange Fox fork, you can definitely tell there are differences. The all-black fork is conveniently much harder to pick out in photos, and doesn’t stand out to the casual observer.

The photo from @CyclingWorlds is more clear, but the fork is just peeking out from behind the lead rider. But again, where you would normally expect to see the start of the arch on a Step-Cast 32 or 34, you see exposed stanchion and a straight line across the front of the lower. The only way for the front of the fork to look this way is if the arch is in the back (or if there was somehow no arch at all โ€“ highly unlikely).

Update:

We love our readers. After reading this story, James Meezan reached out to us and offered up these two photos which give a much better look at the reverse arch of the new fork. Now we can definitively say it’s a reverse arch design, with an arch that looks far more burly than the one on the Taper-Cast 32 Gravel fork.

We can also see that at least of the bikes has a remote lockout on the front. The other bike appears to be a Scott based on what looks to be a TwinLoc lever, meaning it likley has a remote lockout as well.

Nice find, James!

Second Update:

Thanks to Raoul and Dean who both sent this in, we now have a better look at the front of the fork as well on Haley Smith’s bike. Between the World Championships and the Leadville 100, Fox seems to have had a coordinated soft launch of the RAD fork in the wild. As we learned with the development of the Taper-Cast 32 Gravel fork, RAD is Fox’s Racing Application Development program. And just like that gravel fork, we seem to be getting an intentional leak from Fox teasing the new fork as it’s developed with the world’s best racers.

Why Reverse Arch, Why Now?

As we recently learned during the development of the Fox Taper-Cast gravel fork, Manitou’s patent on the Reverse Arch design expired in 2021. It seems that the benefits of a reverse arch were enough to entice Fox to try it out on their gravel forks, so it makes sense they might be developing an XC fork around the same idea. Like the Fox Taper-Cast 32 Gravel fork, maybe the reverse arch allows Fox to make a lighter or stiffer XC race fork?

We’ve also heard rumors that for new tech to be used in the 2024 Olympics in Paris, it must be used this year at Worlds. That may suggest that we’ll see something launch before next August.

Without a clear picture of the arch itself, it’s hard to say what Fox is up to. But there is plenty of evidence to suggest that the next XC race fork from Fox may have a reverse arch.

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Michael
Michael
1 month ago

That rule that to run equipment in the Olympics it must be used at Worlds is no rumor, Bike Rumor. Just ask Stromm Cycles. They were working hard to get someone on a new track bike so it could be used in the Paris games. And they were succesful. Thanks for the article here though. Good digging on your part.

Last edited 1 month ago by Michael
blackwatercyclist
1 month ago

I love a reversed arch fork. With frames becoming more slack in their head tube angles, there is no longer an issue of clearance. Previous reverse arch forks did have longer axle to crowns, like the DT Swiss forks, to allow for more clearance from the downtube. The idea behind a reverse arch is that it takes less distance to connect both sides of the fork so it will be lighter and stiffer than a forward arched fork. Great find here BR!

Robert
Robert
1 month ago

Manitou have had reverse arch forks for many years .

Jaap
Jaap
1 month ago

How does that work? Why would a forward arch take more distance than a reverse arch?

Dirt McGirt
Dirt McGirt
1 month ago
Reply to  Jaap

Science.

Xc_racer
Xc_racer
1 month ago
Reply to  Jaap

Axle is offset forward, so an arch on the front of the fork has to clear the full diameter of the tire.
An arch on the back of the fork can be lower because of that offset.

Useless
Useless
1 month ago
Reply to  Xc_racer

Still the same radial distance from the axle; the lowest position of the arch is still determined by the tyre diameter, so in that respect there isn’t a huge advantage moving the bridge from front to back…?

Fox’s motivation for this design decision may be slightly different. Unless, of course, you need to brace at least one leg of the fork against large forces which are coming from some other location, not the axle. ๐Ÿ˜‰

Last edited 1 month ago by Useless
Jaap
Jaap
1 month ago
Reply to  Xc_racer

Maybe I’m seeing this all wrong, but since the front wheel has a set radius, the distance between the axle and arch will always be the same right?

Milessio
Milessio
1 month ago
Reply to  Jaap

The fork leg is offset from a radial line from the axle. The difference will be a few mm. However, a rear brace couild be shaped to act as a snowplough, stopping mud & stones from blocking the wheel. So it shouldn’t need so much clearance as one in front & could be closer to the tyre & therefore cancelling any weight increase. That would be my logic.

Diem
Diem
1 month ago
Reply to  Jaap

Itโ€™s because of the fork offset; the axle is in front of the casting, so the distance the arch has to span to reach over the tire is greater on the front than the back of the fork. This makes the reverse arch lighter and stiffer. Itโ€™s why the mezzer is super light and super stiff (among other reasons). It also helps protect the stanchions from debris coming off the tire

Jaap
Jaap
1 month ago
Reply to  Diem

Ahh right, so it’s the vertical distance from the top of the lowers/casting, right?

Not the distance from the axle or the horizontal distance between the fork legs. I got that wrong from the other comments.

Dirt McGirt
Dirt McGirt
1 month ago

Lemme fix that headline:

Fox Make a Manitou question mark!?

Nick
Nick
1 month ago

Fox just copying Manitou’s homework. I’ll stick with the original, thanks!

Nik
Nik
1 month ago
Reply to  Nick

Manitou just copying Pace….;-) the first manitou forks had a forward arch.

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