How to service your bottom bracket
Kill the creak. Keep the cranks spinning smooth.
The bearing your cranks spin on. A notchy or creaking bottom bracket robs watts and gets worse fast. Servicing means removing the cranks, inspecting or replacing the bearings, and torquing everything to spec for the standard you run.
Shimano
Hollowtech II — external threaded cups, 24 mm steel axle. The workshop default.
Torque specs
| External BB cups | 35–50 N·m |
|---|---|
| Left crank pinch bolts | 12–14 N·m |
| Preload cap | snug (0.5–0.7 N·m) |
Manufacturer-claimed — always confirm against your model manual.
Video walk-throughs
How to service a Hollowtech II bottom bracket
Park Tool
Shimano BB install & crank preload
GCN Tech
Opens a YouTube search — we link out rather than embed unverified videos.
Manuals & documents
Further reading
Mechanic's tips
- Grease the threads to stop the classic BSA creak.
- Left-side cup is reverse-threaded on English BSA shells.
Tools you'll need
BB tool for your cups
External-cup splined tool or Park BBT-series
Torque wrench
Nm-accurate for cups + crank bolts
Bearing press / extractor
Press-fit standards only
Grease + degreaser
Anti-seize for threads
Plastic mallet
Persuade press-fit cups
Step by step
- 1
Remove the cranks
Undo the non-drive crank cap + pinch bolts, then slide the axle out.
- 2
Extract the BB
Unthread cups (threaded) or press out the cartridge (press-fit).
- 3
Inspect & clean the shell
Check bearings for notchiness; clean threads or bore fully.
- 4
Grease everything
Threads get anti-seize; press-fit bores get assembly compound.
- 5
Install to torque
Thread or press the new/serviced BB and torque the cups.
- 6
Refit cranks & set preload
Snug the preload cap, then torque the pinch bolts.
- 7
Test
Spin for smoothness, rock the cranks for play, ride to confirm no creak.
Frequently asked
How do I know if my bottom bracket needs servicing? +
The classic signs are a creak that gets louder while pedalling out of the saddle, a gritty or notchy feel when you spin the cranks by hand with the chain off, or play you can feel by rocking a crank arm side to side. Any of those means it is time to strip and inspect.
Which bottom bracket standard do I have — threaded or press-fit? +
Look at the shell: a threaded BSA/Italian BB has visible threads and the left cup unscrews clockwise (reverse-threaded). Press-fit shells (PF30, BB86/92, BB30) are a smooth bore with no threads — the cups or bearings press straight in. Check your frame manual if unsure before you buy tools.
Can I service my bottom bracket without a press? +
Threaded standards (BSA, T47, DUB threaded) only need a splined cup tool and a torque wrench — no press required. True press-fit standards (PF30, BB86/92, BB30) need a bearing press to seat the cups squarely; forcing it with a mallet alone risks a crooked, creaky install.
How often should I service a bottom bracket in South African conditions? +
Every 10 000 km or 24 months is a sound baseline for sealed-bearing units, but dusty gravel, Cape winters and coastal salt air all shorten that. If you ride mixed-surface or coastal routes often, inspect at every drivetrain clean and expect to service sooner.
How we source this
- Torque figures are manufacturer-claimed, sourced from each brand's published service/dealer manuals — always confirm against your specific model's manual before you tighten anything, since values vary by generation and material.
- Steps and intervals reflect general industry practice for each standard (BSA, PressFit, T47, BB30); your frame or crank manufacturer's instructions take precedence if they differ.
- Video links point to the named creator's own channel; where we cannot verify a specific real video ID we link out to a YouTube search rather than fabricate an embed.
- We do not sell bottom brackets or tools referenced here and receive no commission for the recommendations — this is workshop guidance, not sponsored content.