How to Remove & Replace an MTB Crankset

Replacing a mountain bike crankset is one of those jobs that looks intimidating but is well within reach for most home mechanics. Whether your crankset is worn, creaking, or you're upgrading to something better, the process follows the same straightforward steps regardless of the bike.

What You'll Need

Before you start, gather the right tools. Most MTB cranksets require a torque wrench, a crank puller tool, and Allen keys in either 8mm or 10mm depending on your crank bolt. Some self-extracting cranksets need nothing more than a hex key. Check your specific crank before you begin.

1. Removing MTB Cranksets that use Outboard BBs

The following steps apply to cranksets from Shimano, FSA, and SRAM that run on a fixed axle to a crank arm. Start by shifting to the smallest chainring and smallest sprocket to reduce chain tension. Remove the crank bolt or preload cap on the non-drive side, then slide the non-drive crank arm off the spindle. If it's stuck, a crank puller tool threads into the arm and pushes against the spindle to free it without damaging the threads. Move to the drive side and repeat the process, lifting the chainring carefully away from the frame to avoid scratching the chainstay. Once both arms are off, slide the spindle out through the bottom bracket.

For Middleburn and Race Face cranksets, the process is different. Undo the extracting bolt on the drive side, which extracts the drive side arm off the axle. You can then slide the non-drive side arm and axle assembly out from the bottom bracket.

2. Inspecting the Bottom Bracket

With the crankset removed, take a moment to check the bottom bracket by spinning it with your finger. Any roughness, grinding, or play is a sign it needs replacing before the new crankset goes in. Fitting a new MTB crankset onto a worn bottom bracket shortens its lifespan from the start.

3. Installing the New Crankset

Clean the bottom bracket shell and spindle contact points before fitting.

For Shimano, FSA, and SRAM cranksets, slide the drive side in first, seating the chainring clear of the frame. Fit the non-drive arm, making sure it's correctly clocked at 180 degrees to the drive side. Torque the crank bolt to the manufacturer's specification, typically between 12 and 14Nm, though always check your specific crankset.

For Middleburn and Race Face cranksets, slide the non-drive side arm and axle assembly into the bottom bracket bearings until the axle appears on the drive side. Slide the drive side crank arm onto the axle and tighten the bolt to the manufacturer's recommended torque settings.

Check for any play once fitted and recheck torque after the first ride.

Shop MTB Cranksets

At BETD, we stock a full range of bicycle cranksets manufactured in the UK to precise tolerances, from our renowned Middleburn cranks and chainrings range. Whether you're replacing a worn crankset or upgrading for better performance, shop online today to find the right cranks for your bike.