Freehub Removal, Installation and Service

Level of Difficulty: Intermediate

Typical Tools and Supplies Needed [1]

• Cone wrenches
• Combination wrenches, sizes vary.
• Hex wrenches: 10mm for Shimano®, some brands use an 11mm or 12mm.
• Pencil Magnet and seal pick
• Compressed air and blowgun
• Grease
• Solvent
• Axle vise
• Rags

Freehub Service

This article will discuss the service of freehubs. The freehub is the ratcheting mechanism attached to the rear hub of most modern derailleur bike hubs. The freehub uses a splined cylinder to hold the cassette cogs. Inside the freehub mechanism will be bearings and a clutch system, usually ratcheting teeth and pawls. The cassette cogs have no moving parts. All moving parts are in the freehub body. Details of freehub designs difffer between manufacturers and you should refer to manufacturer's literature as well as the following instructions.

Most rear hubs allow the freehub body to be removed. The body can then be flushed with solvent for cleaning, dried, lubricated with oil, and then re-installed. Much of the process is similar to a hub overhaul. To service the freehub, begin by removing cassette cogs.

The common Shimano® freehub uses internal loose ball bearing, pawls and springs. Be aware that it is not recommend to completely dismantling the freehub itself. There are no parts available, such as the pawls or springs. The small ball bearings are available as replacement parts. However, if the bearings are worn out and require replacing, it is very likely the entire freehub is needing replacement. The blow-up image seen below is a ball bearing type freehub.

The freehub pawls and bearings operate only while the bike is coasting. There is very little load or stress on the freehub during this time. When the bike is pedaled, the pawls lock onto the ratcheting teeth, and the freehub bearings take very little stress. Because of this, bicycle grease is typically not required inside a freehub. Most manufacturers recommend liquid lubricant for the inside of the freehub. With enough use, the freehub will simply wear out. The pawls may begin to slip and the bearings may become rough. If cleaning and lubricating the freehub does not resolve issue of slipping, sticking or noise, replace the freehub unit with a new one.

Freehub Service: Shimano® and loose ball bearing types

The procedure below is based on the Shimano® freehub removal process. Several other brands follow the same steps.

1 Remove axle as during hub overhaul. See Hub Service if you are unfamiliar with this process.

2 Use a hex wrench to loosen and remove the freehub holding-bolt. Most brands are accessed through the right side, but a few are accessed through the left side. The bolt is typically very secure and may require much effort to loosen.

3 Note any spacer behind freehub.

4 Gently remove any seal behind freehub body.

5 Flush freehub in solvent, spinning body to remove dirt. NOTE: Do not attempt to pry out right side dust cap from Shimano® freehubs. Damage may result. Clean under dust cap using a brush and rags. Clean area above cap as well.
    

6 Blow dry with compressed air. Use normal precautions when using compressed air. If no compressed air is available, allow freehub to sit until completely dry.

7 Use a liquid lubricant in the back side and front. Spin freehub to work lube inside.

8 Grease freehub mounting-bolt.

9 Install freehub and any spacer onto hub body. Thread in freehub mounting-bolt and secure fully. Tighten to about 360 inch-pounds. If you are holding a wrench 6 inches from the bolt, apply 60 pounds of effort.

10 Assemble and adjust hub as with hub overhaul.

American Classic® freehub

The American Classic® freehub contains cartridge bearings. These may be removed and replaced.

Freehub Removal

1 Hold drive side axle securely in an axle vise.

2 Hold non-drive side sleeve nut with cone wrench and loosen locknut counter-clockwise. Pressed-on axle cap will prevent locknut from being completely removed. Make sure locknut is spinning freely and is not engage on thread.

3 Loosen sleeve nut. Sleeve nut will press against locknut and act as a press to remove axle cap. Remove cap, locknut and sleeve nut.

4 Remove axle by pulling on drive side.

5 Pull freehub to remove from hub shell. Pawls are inside hub shell. Clean and flush all ratcheting parts. Use care not to get solvent in cartridge bearings.

6 Grease the pawls and teeth of the freehub. Install freehub into shell.

7 Install axle and assemble non-drive side parts. Axle should turn smoothly with no side-to-side motion after adjustment.

8 Install non-drive side axle cap.

DT-Hugi® Freehubs

The DT-Hugi® freehub uses cartridge bearings inside the body.

1 Pull on freehub body to remove from shell. This will remove drive side axle cap and freehub body.

2 The clutch is composed of two gears. The angled teeth face one another. The gear inside the hub shell rides on a spring.

3 Clean parts. Use care not to get solvent in cartridge bearings.

4 Grease gears and spring.

5 Install one gear inside freehub with smooth side facing freehub, and toothed side facing hub shell.

6 Install spring inside hub shell, with small end facing toward freehub.

7 Install second gear into hub shell, with smooth side facing hub shell and teeth side facing freehub body.

8 Slide freehub onto axle and press to seat freehub over seal.

9 Install drive side axle cap.

Campagnolo® Freehub

Chorus and Record freehubs are held on by the axle. The freehub body holds cartridge bearings. The axle is independent of the freehub.

1 Remove set screw from side of drive side locknut.

2 Hold non-drive side cone with cone wrench. Loosen and remove drive side locknut.

3 Pull freehub to remove. Use care not to loose small parts. Note orientation of pawls as you remove freehub.

4 Clean parts as needed.

5 Grease springs and pawls, and install into freehub.

6 Engage freehub inside hub shell. It can be difficult to engage pawls into hub shell. If necessary use the Campangolo® UT-HU080 tool. You can also tie a string around the pawls to help engage it into the shell, then pull the string loose.

Suggested Park Tools

• DCW and SCW series cone wrenches wrenches.
• Hex wrenches: 10mm for Shimano®, some brands use an 11mm or 12mm.
• Park Tool Polylube® 1000 grease
• Bio ChainBrite® solvernt
• AV-1, or AV-3 axle vise