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Wild new Fox 32 Step Cast XC fork is just 1,287g

2025 fox 32SC with reverse arch is the lightest xc mtb fork
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The all-new Fox 32SC fork introduces a wild new reverse arch design that combines with the new GRIP SL damper to become the lightest modern 29er fork on the market.

Claimed weight is just 1287g, down from 1388g for the prior model! Yet it’s also stiffer and more capable than ever, giving cross country and marathon racers a big leg up over gravity.

cutaway internal view of 2025 fox 32SC mtb fork

The claimed 100+ gram savings is even more impressive considering it’s compared to their prior 27.5” size, which was the lightest they offered until now. But new one is 29er only, so, apples to apples, this one actually saves a good bit more than 100g!

Here’s where the weight savings came from

  • -65g from the new damper
  • -9g from double-butted upper tube on damper side
  • -9g stiffness optimized crown
  • -11g ultralight steerer tube
  • -12g Kabolt SL
  • -1g ultralight cable guide

The air spring’s upper tube needs straight walls inside to maintain a consistent seal with the piston, so the tapering is only on the damper’s upper tube.

The lowers are actually a couple of grams heavier, but most of the improved stiffness comes from the lowers, so it was a tradeoff worth making.

The new Kabolt SL keeps the same tooled design and external profile as the original Kabolt thru axle, but gets internally machined butting to save a few extra grams of unsprung weight.

Who’s it for?

cutaway internal view of 2025 fox 32SC mtb fork

With many XC bikes now running 110-120mm fork travel, Fox is mostly aiming this one at the multi-hour and multi-day marathon stage racing crowd. It only comes in 100mm travel, with the air spring and damper optimized specifically for that.

That said, we saw it being tested in the XCO World Cup races last year, so the new design is clearly stiff enough for aggressive racing on modern courses, too. Fox says it’s 40% stiffer, getting it really close to the torsional stiffness of the 34SC!

And the new GRIP SL damper (read this story for a deep dive on the new 2025 GRIP damper tech) provides quicker, smoother selection of lockout and pedal modes with an optimized compression circuit that reacts more quickly to impacts for more control.

Why a reverse arch?

closeup detail of reverse arch on new fox 32SC xc marathon mtb fork

The new generatively designed rear arch lets them bring the arch a bit lower, which lets them use less material to achieve the necessary stiffness. This is possible because the 32 SC has no fork offset at the crown, so it can stay tucked in without worrying about it hitting the downtube under full compression.

To get the fork’s 44mm offset, they angled the legs from the crown, so the lowers are not sliding in the same plane as the steering angle during compression and rebound. This gets into issues of transverse sheer forces, which is something that works fine for this short-travel application, but isn’t really something they can do on longer-travel forks.

So, Fox says you won’t see them port this design over to other mountain bike forks in the future.

What else should I know?

The Step Cast design requires a 2mm hex tool to externally adjust low-speed rebound damping, and a tool will come with the forks. That differs from the Taper Cast forks using the GRIP SL damper (like their gravel fork) will have a built-in knob. And, just thinking out loud, since that gravel 32TC fork has less travel than the 32SC, perhaps it could use a reverse arch to save weight…

RideFox.com

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Eddiecycle
Eddiecycle
1 month ago

Don’t quite understand that last sentence. 32TC already has a reverse arch

Nathan
Nathan
1 month ago

What’s our tire clearance, Clarence?

Bumscag
Bumscag
1 month ago

Uhhh… Most forks have forward offset at the crown, so a reverse arch has less chance of hitting the downtube than a zero offset crown. Did you mean hitting the crown?

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