A big box from Fox HQ in California turned up at the Dirt office today. Among some other bits was a set of the new Fox 831 4x, dirt jump forks. I remember seeing Jared Graves and Dan Atherton with a pair of these bad boys at the World Champs in Canberra.
This is the first dirt jump/4x/dual slalom specific fork from the Fox mob and looks the business too. It runs a 15mm bolt-thru but there should be plenty of conversion kits around if you run a 20mm hub. They weighed in at 1723g on our office scales and word has it they’ll cost £749 and be available around December time just in time for Christmas and an expensive Christmas present at that. When we’ve had a thorough testing and hammering we’ll let you know if they are worth it.

Designed and engineered for the demanding disciplines of 4X, Dirt Jump, and Dual Slalom, the 831 uses the FOX
32 mm platform, FLOAT® Air Spring technology, and FIT RLC damper. The 831’s FIT RLC damper is specifically valved with firmer low- and high-speed compression damping to increase pedaling efficiency when sprinting out
of the start gate and absorbing large jump landings.The FLOAT air spring has been designed to add more progression, to push back on the rider during high cornering loads, and help better control bottom-out. Travel is factory set at 100 mm, and is internally adjustable from 80 to 100 mm in 5 mm increments for optimal crown-to-axle height tuning. The chassis has increased stiffness at this travel due to the use of FOX’s longer travel chassis components normally found on the 32 FLOAT, TALAS®, and Vanilla® forks.

Spec

WEIGHT (15QR-includes axle)
3.83 lbs / 1.74 kg (1 1/8″ steerer)
3.8 lbs / 1.73 kg (1.5″ taper steerer)

TRAVEL
3.9 inches (100 mm)- Travel is internally
adjustable from 80
to 120 mm

ADJUSTMENTS
– Low-speed compression- Travel (internally adjustable)- Air spring pressure – Rebound

DAMPER
NEW FIT damper valved for
4X and Dirt Jump

LOWER LEG
– Webbed-brace with 15QR
thru-axle system
provides maximum stiffness- Post style disc brake mounting

STEERER
Standard: 1 1/8″
Optional: 1.5″ Taper

SPRING
Air

FORK COLOR
Black