If you start hearing crunching when your rear wheel is spinning or if the rear wheel seizes up completely, you know it’s time to overhaul your freehub. Or, if you have a freewheel, you’ll need to completely replace the freewheel since it’s a functioning system that can’t be taken apart.

Not sure whether you have a freehub or a freewheel? (Check out this article with videos)

These instructions teach you how to overhaul a sealed freehub, like Shimano, because it’s the most common style of freehub for mountain bikes.

What tools do I need to overhaul my freehub?

Tools to Assemble an MTB Wheel
Tools to Assemble an MTB Wheel
  • Chain whip
  • Lockring remover/ cassette lockring tool
  • Adjustable crescent wrench
  • 10mm and 12mm Allen keys
  • Allen key multi-tool
  • Screwdriver with magnetic tip
  • Cone spanners
  • 17mm spanner

Directions for overhauling your freehub

1.Remove the cassette

  • Remove the rear wheel.
  • Use a chain whip to keep the wheel from spinning. Choose a gear ring that allows the chain whip to wrap around all the teeth on the ring.
  • Insert the lockring remover tool. Make sure the splines are lined up and fitting snuggly and the tool is inserted as deeply as it will go to prevent stripping.
  • Fit the crescent wrench onto the lockring remover, lining the handle up slightly to the left of the chain whip handle to enable a two-handed grip. Squeezing your hands together, unscrew the lockring and cogs.
Freehub Assembly
Freehub Assembly

2. Check to see if you need to replace the freehub

Firmly grasp the splined freehub body and wiggle it. It shouldn’t move more than a couple millimeters side to side. If it does, you’ll need to replace the freehub body. Otherwise, an overhaul with cleaning and reapplication of lubrication will serve just fine.

3. Remove axle and ball bearings

  • Use a 14 or 15mm cone spanners on the left side and (usually) 17mm spanner on the right side to loosen the left locknut.
  • Unscrew the locknut, then the cone and withdraw the axle assembly.
  • Use a clean rag to catch ALL the loose ball bearings!

4. Remove the freehub body

Insert a 10mm Allen key into the hollow bolt holding it in place from the right (drive side) and turn counter-clockwise. You may want a longer Allen key or a handle extension to provide enough power to dislodge the bolt.

5. Clean and lube the freehub body and ball bearings

  • Use a spray degreaser like WD-40 or GT-85 and wear goggles. Spray the freehub’s internals until you can’t feel dirt or roughness.
  • Apply a generous amount of wet lube.
  • Allow to drain. Wipe, then do another application of wet lube.
  • Replace the seal.
  • Grease the splined surface of the hub shell and re-install the freehub body.
  • Re-torque the bolt firmly. Wipe away any excess oil.
  • Wipe the ball bearings completely clean, feeling for pits and divots. Any ball bearings that aren’t completely round and smooth should be replaced. (Worn bearings are actually the primary cause of rough-spinning wheels.)
  • Reassemble the axle and reinsert the ball bearings. This will be much easier using a magnetic-tipped screwdriver to place them properly in the grease.
  • Remount the cassette, being sure to tighten the lockring back on the stack.
  • Return the rear wheel to the bike.

When should I service my freehub?

There’s not really a standard amount of ride time or mileage to set up a schedule for servicing your freehub. If the system remains well sealed against dirt and water, you can ride indefinitely without overhauling or servicing your freehub. But dirt and water wear away the lubrication that allows the pawls inside the freehub to move smoothly. Once dirt and water are wearing out the inside of the freehub, it’s important to service it immediately before the wear causes actual damage to the parts.

Can I Upgrade My Freehub?

Do you love hearing that buzzing click on your buddies bike? Many higher end hubs have more “engagement” pawls that snap over the gears making that buzzing. With more pawls you have a increased engagement of the hub.

Can you upgrade – YES.

Bike Hub Prices

Like so many parts for mountain bikes the prices are wide ranging. You can go low cost like a Shimano Deore at around $45 or a Scram X0 for $200. Below is a little price table to prepare you.

Brand and Model Price as of 2022 on Amazon
Walgun Front and Rear Hub Set$43.00
Shimano Deore$44.00
Shimano XT$66.00
Shimano SLX$90.00
Scram X0$199.00
Scram 746$66.00

If you were to ask me what to get, for the price I’d recommend a full wheel with rim, spokes and hub. If you’ve never strung up a wheel and don’t have a wheel stand. Putting a complete wheel together is difficult. Park Tool has a video – HERE.

A 29 inch full wheel with a generic hub will cost less than $100.

What Freehub Size Do I Have

MTB compare old 100mm hub with 110mm hub
MTB compare old 100mm hub with 110mm hub

I’ve got a complete article explaining hub sizes and measuring what size you need in this article 👉 What’s the Difference Between QR and Thru Axles and to support you even more check out my article on axle threads.

What is a Boost Hub

You can’t talk about MTB hubs without discussing “BOOST”. Boost referrers to the width of the hub (which is continuing to get bigger). A standard REAR hub is 142mm wide, a Boost is rear hub is 148mm and a Super Boost rear is 157mm. I’ve got this described and ways to convert your wheels in this Article Converting a Boost Bike Wheel and Frame.

Places to Get Rear Bike Hubs

Like most folks, Amazon seems to be the place we turn to to shop. But I’m going to recommend talking to a local bike shop, rear hubs affect the brakes, gears, and chain line of your bike.

Looking for Some More Ways to Help Your Bike Last

Kat Jahnigen Writer

Professional writer Kat Jahnigen was 2 miles from the nearest village – and roughly 2,310 miles – from the nearest English-speaking town – when her bike tire burst. At that time, she was a college student on a bike trip across the desolate, rocky island of Crete. It suddenly occurred to her that it would’ve been good to learn some basic bike repairs before setting off on a solo bike trip.

Check out Kat’s website WriteHire at writehire.net.