Sprocket: turning, replacing, splined

The SPEEDHUB has a single sprocket, so it lasts a long time — and most sprockets are reversible: when one side is worn, turned round it runs on the unworn tooth faces. Always fit a new chain when turning or replacing a sprocket, as the pitch of old and new tooth faces no longer matches.

Sprocket	Reversible?
splined (Splined Carrier), 13–21 teeth	yes
threaded, 15, 16, 17 teeth	yes
threaded, 13 teeth	no — replace it when worn

Turning or replacing a threaded sprocket

You need a sprocket remover (8501 for 135/170 mm, 8508 for 142/177 mm, 8509 for 148/190/197 mm), a 24 mm spanner and a chain whip.

1. Clean the sprocket and the hub shell around it so no dirt gets into the gearbox. Put the remover on the driver and secure it with the quick release (CC) or axle nut (TS) — so its teeth cannot slip out.

   

2. Hold the remover with the 24 mm spanner and unscrew the sprocket with the chain whip against the drive direction. A sudden, firm push helps break it loose.

   

3. Check the sprocket: if the shaft seal has left a track on it, turn it round; if both sides are marked, use a new sprocket with intact sealing faces, or oil can leak.

   

4. Clean driver and sprocket, grease the thread, and screw the sprocket on clockwise over the fitted remover — which centres it. Tighten it with the chain whip, in gear 14.

Caution

Do not clamp the remover in a vice, and make sure it fits tightly — otherwise the driver can be damaged.

Tip

A drop of Rohloff cleaning oil (Art. no. 8402) on the shaft seal through the new sprocket’s holes reduces the cranks turning when you push the bike.

Converting to a splined sprocket

Every SPEEDHUB can be converted to the Splined Carrier system. The sprocket slides onto a carrier and is held by a circlip — so it can be turned and replaced without tools, and the range runs from 13 to 21 teeth.

Carrier	Sprocket	Chainline, 135/142 mm frame	Chainline, 170–197 mm frame
8540 — standard (13.5 mm)	13–21 teeth	57 mm	75 mm
8540S — narrow (11.5 mm)	15–21 teeth	55 mm	73 mm
8540L — with lock ring, for Gates belts	splined belt sprocket	55 mm (148 mm: 52 mm)	73 mm

1. Slide the splined sprocket fully onto the clean carrier, fit the circlip by hand and snap it into its groove. Check it sits tight, and lightly grease the carrier thread.

2. Clean the hub shell and driver, and remove the old threaded sprocket as above.

   

3. Wipe the driver and the shaft seal, and carefully screw the assembled unit on over the remover as a guide, to the stop. Tighten it with the chain whip, in the drive direction.

   

4. Fit the wheel and check the chainline and chain tension. With a chain tensioner, the upper pulley must line up with the sprocket — with the long frame bolt (Art. no. 8257) if needed; 148/190/197 mm frames or direct-mount hangers need the Kettenspanner-10 (Art. no. 8250-10). See Chain tensioner and chain guide.

If the sprocket turns stiffly

Turned backwards, the sprocket should spin easily with no real resistance. If it is stiff, the sprocket-side shell bearing is preloaded. One firm blow with a plastic mallet on each axle end — once on the sprocket side, once on the axle-ring side — releases it.

Clearance check

The splined sprocket’s chainline is 3 mm further out, so on frames with flat chainstays and large sprockets, chain or sprocket can touch the chainstay or dropout. The turning hub shell and carrier must touch nothing. A full chain guard or chain case can collide too — if in doubt, ask us.

On chainline and gearing, see Chainline and gearing; for Gates belts, Gates belt drive.