Bike torque specs chart

The chart first, then the explanations. Every figure comes from the component maker's own manual — Shimano and SRAM dealer manuals, Park Tool's compilation of the rest — and the source is named on each row. One rule outranks the whole table: a number printed on the part wins. This chart is for the bolts that don't say.

Ranges are the manufacturers' published figures; where a value is printed on your part, use that instead. Preload fasteners (shaded) are adjusted for zero play, not torqued to a target. Carbon parts: the carbon component's own limit wins — see below. Inch-pound figures are converted and rounded. Sources: Shimano and SRAM dealer manuals for their components; Campagnolo and Look for theirs; Park Tool's cross-brand compilation for stems, seatposts and bottom brackets. Each row names its source on the web page.

How tight should bike bolts be?

Tighter than most people think for the big fasteners, and much less than most people think for the small ones. A cassette lockring wants 40 N·m; a seatpost collar wants 4–6 — a tenth of that — and a stem faceplate on a carbon bar wants 5. The problem is that the small numbers are the ones holding your handlebars on, and the ones that crack a carbon part when a hand "just snugs it up". A torque spec exists because the bolt has to be stretched enough to clamp under vibration and not so much that it strips its thread, crushes the tube it's clamping or fatigues and snaps. That window is wide on a steel crank bolt and narrow on an M5 bolt into a carbon steerer, which is why the chart is worth having.

N·m to in-lb: reading a spec in your wrench's units

Manufacturers publish in newton-meters; most US torque wrenches are marked in inch-pounds (small) or foot-pounds (large). The toggle above prints the chart in either. For a spec that isn't on it:

1 N·m = 8.85 in-lb = 0.738 ft-lb; a wrench marked in kgf·cm reads about 10× the N·m figure. Rounded to the nearest in-lb.

What does 5 N·m feel like?

Torque is force times lever, so a spec is really a statement about how hard to pull at the end of your tool. Divide the torque by the tool's length and you get the pull:

Pull at the very end of the tool, perpendicular to it: force = torque ÷ lever length. 100 mm — a folding multi-tool or short Allen key; 150 mm — a long L-shaped Allen key; 300 mm — a cassette or crank wrench. Gripping the key closer to the bolt raises the required pull in proportion.

Which spec wins when two parts disagree?

The weakest part in the joint sets the limit. A bolt's torque is limited by whatever it's clamping as much as by the bolt itself, so when a stem says one thing and the bar inside it says another, the lower maximum rules. Worked for the commonest case: an alloy stem rated 5–8 N·m holding a carbon bar rated 4–5. The joint is a 5 N·m joint — the bar's ceiling, not the stem's — and the stem's printed 8 is irrelevant the moment a carbon bar goes into it. The same logic covers a carbon seatpost in an alloy frame collar, a carbon steerer in an alloy stem, and carbon saddle rails in any post.

Torque specs for carbon parts

Carbon doesn't yield and dent the way aluminum does; it holds, holds, and then cracks — often invisibly, inside the clamp, weeks before it fails. So the carbon rules are stricter than the numbers alone suggest:

• The carbon part's own figure is the ceiling, whatever the clamp says. Most carbon bars, posts and steerers are rated 5–6 N·m; some aero bars are lower.
• Use friction paste, not grease, at every carbon-to-clamp interface. It lets the part hold at the low end of the range.
• Tighten in steps, in a cross pattern on four-bolt faceplates: bring all four to 2, then 4, then the target, so the plate stays parallel and no single bolt carries the load.
• No overtightening to cure slipping. A carbon post that slips at 5 N·m needs paste or a better collar, not 8.
• Inspect the clamped zone at every service: a white stress mark or a crackle under thumb pressure retires the part.

Which torque wrench do you need?

No single wrench does the whole bike accurately — a click wrench is reliable in roughly the middle 80% of its range and vague at both ends. Counted against the 31 torqued rows in the chart above:

A row counts as covered when its whole range sits inside the wrench's. The preset 5 N·m key covers the bolts that most often break carbon; the small click wrench is the one to buy first; the large one is only needed the day you change a cassette or crank.

The bolts that aren't torque specs

A few fasteners have a number in the chart but shouldn't be tightened to it. They're adjusters: their job is to remove play, and the real clamping is done by a different bolt afterward.

Overtightening the headset top cap is the classic error: the steering goes stiff and the bearings wear, because the cap was never meant to hold anything. Set preload until the fork stops knocking under a front-brake rock test, then torque the stem's steerer bolts — those are the ones doing the work.

What happens if a bolt is too tight — or too loose?

Notice the asymmetry. On the big steel fasteners, too loose is the dangerous failure and too tight is nearly impossible by hand. On the small bolts into carbon and thin alloy, too tight is the dangerous failure and the damage is often silent. The chart's shape follows: hit the number on the big ones, never exceed it on the small ones.

How to use a torque wrench properly

1. Clean and prepare the threads the way the manufacturer expects — a light grease or thread-locker on steel-into-alloy, friction paste on carbon interfaces, nothing on rotor bolts with a locking patch.
2. Set the wrench, then pull smoothly at the end of the handle until it clicks once. Stop. A second click adds torque.
3. Multi-bolt clamps go in steps, cross pattern — faceplates, two-bolt saddle clamps, crank pinch bolts, rotor bolts.
4. Never use it to loosen, and never as a breaker bar; both throw the calibration.
5. Wind a click wrench back to its lowest setting for storage, and have it checked (or check it against a known weight on a known lever) every year or two.
6. Recheck new installs after the first ride — stems, cleats, saddle clamps and square-taper cranks all settle.

Where these numbers come from

Shimano's and SRAM's dealer manuals for their own parts (cranks, derailleurs, brakes, rotors, cassettes, pedals), Campagnolo's and Look's for theirs, and Park Tool's compilation of stem, seatpost and bottom bracket figures across brands — each row on the chart says which. Where two makers publish different numbers for what looks like the same bolt, the chart keeps both: Shimano's 6-bolt rotor bolts are 2–4 N·m, SRAM's 6.2, and averaging them would be wrong for both. Where your frame, fork or component maker publishes a figure — printed on the part or in its manual — it replaces the chart. If you think a row is wrong, the corrections address goes to a person.