27.5-inch MTB forks

How to choose your 27.5-inch MTB fork

27.5-inch remains the format for gravity bikes, smaller frame sizes and the front of full 27.5 setups. The range covers the entire spectrum, from entry-level cross-country to enduro forks with 38 mm stanchions.

Travel, within the frame's limits

• 100 to 120 mm : cross-country and trail riding.
• 130 to 150 mm : trail and all-mountain.
• 160 to 180 mm : enduro and downhill, with 36 to 38 mm stanchions.
• 200 mm dual crown : pure downhill.
• Stay within 10 to 20 mm of the frame manufacturer's specified travel: beyond this, frame geometry and warranty coverage are compromised.

Mounting dimensions

• Steerer tube : tapered 1"1/8 – 1"1/2 on modern MTBs, straight 1"1/8 on older ones.
• Wheel axle : 15x110 mm Boost, 15x100 mm, or 20x110 mm on downhill forks.
• Brake calliper mount Post Mount, with the maximum supported rotor diameter.
• Steerer length, to be cut down during installation according to your headset stack height.

27.5 fork on a mullet frame

On a mullet setup, the front wheel is 29 inches: you therefore need a 29-inch fork, not a 27.5. A 27.5 fork is only relevant on a mullet bike if you reverse the setup, which is rare. Conversely, a 29-inch fork will usually accommodate a 27.5-inch wheel with extra clearance—the reverse is never possible.

Air or coil

• Air : the standard, finely adjustable to the rider's weight and tuneable for progressivity with volume spacers.
• Coil : better small-bump sensitivity and consistent performance on long descents, at the expense of weight and the need to select the correct spring rate.

The damper cartridge

This is what sets two forks with the same travel apart. An advanced cartridge delivers better high-speed compression control—handling harsh, sudden impacts—and offers more adjustability. On many models, it can be replaced without changing the entire fork.

To find out more: How to choose your MTB fork

See also: 29-inch MTB forks · MTB rear shocks · Fork cartridges and spare parts