CASSETTE REMOVAL AND INSTALLATION
This article will review the removal and installation of cassette cogs on derailleur-type bicycles. The threaded freewheel system is discussed at Freewheel Removal and Installation.
The rear cogs are attached to the hub in one of two ways. Newer bikes tend to use the type of hub called a “cassette hub.” The cassette hub uses a “freehub” system, which is a type of clutch mounted to the body of the hub. This cylindrical mechanism ratchets counter-clockwise for coasting, and locks clockwise for driving the bike when pedaled. The freehub body has a series of splines on the outer shell. “Cassette” sprockets slide over these splines. A lockring threads into the freehub and holds the sprockets, or cogs, in place. When the cogs are removed, the ratcheting freehub remains on the hub body. Most modern bicycles use the freehub system. See a typical cassette hub below.
Older bikes may have a large external thread machined into the hub. The cogs and ratcheting body assembly, called a “freewheel,” threads onto the hub. The ratcheting mechanism comes off with the cogs when the freewheel unthreads for removal.
This article will review the removal and installation of cassette systems. For freewheel systems, see Freewheel Removal and Installation.
CASSETTE LOCKRING TOOL COMPATIBILITY
You will need to determine the style or brand of cassette you have. The table below shows every style that has a compatible installation & removal tool made by Park Tool.
|FR-5.2, FR-5.2G, FR-5.2GT, FR-5.2H|
|Shimano®, SRAM®, Chris King®, Sun Race®, Hugi®, etc. cassette lockrings||12 splines, approx. 23.4mm diameter|
|Campagnolo® cassettes||12 splines, approx. 22.8mm diameter|
|Single-speed external notch lockring||2 to 8 external notches|
As a rule of thumb, if the bike has a Campagnolo brand shifting system, it is likely it will have a Campagnolo compatible lockring. Use the BBT-5/FR-11 for these bikes.
CASSETTE LOCKRING REMOVAL
If your cogs look like this, you probably have a lockring type cassette.
With the modern cassette cog systems, all cogs are fitted with splines. Cogs slide onto the freehub body and are held in place by a lockring. The lockring sits outward from the smallest cog. Look for the word, “LOCK”, and an arrow on the lockring indicating direction to turn for locking. Turn the lockring counter-clockwise, the opposite way of the arrow, to loosen it. There may be a loud noise when the lockring breaks loose. There is often knurling under the lockring to help keep it in place, and this knurling makes noise when the ring is loosened or tightened.
- Mount bike in repair stand and remove rear wheel from bike.
- Remove quick release skewer.
- Inspect cassette and select correct type of remover.
- Engage remover into splines/notches.
- Install quick release skewer and install skewer nut on outside of remover.
- Snug skewer nut against remover. The skewer acts as a holding device for freewheel removal tool.
- Hold cogs in clockwise direction with sprocket chain whip tool. Turn remover counter-clockwise, using a large adjustable wrench, the hex end of another Park Tool sprocket chain whip tool, or the Park Tool FRW-1 freewheel wrench. It will require force to remove the lockring. Expect to hear a loud clicking sound as the locking teeth of the lockring separate.
- If using a vise, grab removal tool tightly in vise with wheel held flat. Use sprocket chain whip tool to turn sprockets counter-clockwise, as seen from above the hub. Do not hold wheel while turning sprockets, allow wheel to rotate, and pull only on sprocket chain whip tool.
USING FR-5.2G OR FR-5.2GT WITH GUIDE PIN
The FR-5.2G and FR-5.2GT include a guide pin for greater stability during the removal and installation process. Remove the skewer or thru axle and install the FR-5.2G or FR-5.2GT. Make sure the teeth are fully engaged in the lockring. Hold cogs as described above and turn the tool counter-clockwise.
CASSETTE LOCKRING INSTALLATION
Cassette freehub bodies and cassettes are often designed so the cogs will fit in only one orientation. This permits manufacturers to align “shifting ramps” to specification.
- Inspect splines of freehub body. Look for a wide space between splines. Inspect the internal splines of cogs. Look for a wide spline to mate with wide space in freehub body. Align splines and engage all cogs.
- Install spacers in same orientation as when removed.
- Grease threads of lockring and thread lockring into freehub.
- Install cassette lockring tool and install quick release skewer. Thread skewer nut on outside of lockring tool.
- Snug skewer nut against remover. Skewer acts as a holding device for freewheel tool.
- Turn remover clockwise until lockring is tight, at least 360 inch-pounds (approximately 40 Nm). For installing lockring, use of the sprocket chain whip tool is not required.
The FR-5.2G speeds installation as well. Simply insert the FR-5.2G into the lockring splines and tighten fully.
SRAM COMPATIBLE XD FREEHUB CASSETTES
SRAM XD freehubs and sprockets are considered a cassette system. The lockring mechanism is hidden down inside the cassette stack. Inspect the inner perimiter of the smallest sprocket for 12 splines. Use the FR-5.2, FR-5.2GT, FR-5.2H, or FR-5.2G on this fitting.
To remove the cassette, hold it from spinning using a chain whip. Insert the lockring tool (use the FR-5 series), and turn the tool counter-clockwise. The locking ring will unthread from the freehub and the cassette will lift upward.
To install the cassette, lubricate the threads inside the cassette stack. Place the cassette on the freehub body, and use a tool to turn the locking ring clockwise. Secure to approxiately 40Nm.
NON-LOCKRING FREEHUB COG REMOVAL
Older freehubs may lack notches or splines adjacent to the axle. These older freehub cogs did not use a freewheel or cassette lockring removal tool. There will be a dust cap for the hub on the right side, but no recessed notches or lockring splines at all. The first cog acts as a lockring for the other cogs.
- Using two chain whip tools, place first chain whip on second or third cog, holding it clockwise.
- Place second chain whip on first cog to rotate it counter-clockwise.
- Arrange chain whips so they form a “V”. This gives you better mechanical advantage. See image above.
- Rotate first cog counter-clockwise while holding the other chain whip. This loosens first cog. Remove cog and pull off other cogs.
NON-LOCKRING FREEHUB COG INSTALLATION
- Grease threads of smallest cog.
- Install cogs and spacers on freehub.
- Thread on smallest cog and secure clockwise with sprocket chain whip tool.