Torque Specifications and Concepts

This article will discuss the basics of torque and torque wrench use. See also related article on Basic Thread Concepts. This article includes a table of various torque recommendations.

1

Introduction to Torque

Threaded fasteners, such as nuts and bolts, are used to hold many components to the bike. As a fastener is tightened, the fastener actually flexes and stretches, much like a rubber band. This stretching is not permanent, but it gives the joint force to hold together, called “preload,” or tension. Each fastener is designed for a certain range of tension. Too much tightening will deform the threads or the parts. Too little preload will mean the fastener will loosen with use. This can damage components, such as a crank ridden with a loose mounting bolt. Loose bolts and nuts are also generally the source of various creaking on the bike.

Tension in the fastener depends largely upon the amount of torque, the tightening, and the size of the thread. Generally, engineers will specify a thread size large enough to handle the anticipated stresses. For example, the M5 bolt of a water bottle cage bolt would not be a good choice for holding a crank. Even if the bolt were as tight as possible, it would not provide enough force to hold the arm secure to the spindle. The crank-to-spindle interface receives quite a lot of stress, making larger threads (M8, M12, M14) a better choice. The amount of pressure applied by a thread can be substantial in order to hold the joint secure. For example, a fully tightened crank bolt can provide over 14,000 Newton force (3,000 pounds force) as it holds the arm in place.

It is commonly believed that bolts and nuts often come loose “on their own”, for no apparent reason. However, the common cause for threaded fasteners loosening is simply lack of tension during initial assembly. Vibration, stress, use, or abuse cannot typically overcome the amount of clamping force in a properly sized and secured threaded fastener. As a simple rule of thumb, any fastener should be tightened as tight as possible without failure of the thread or the component parts. This means the weakest part of the joint determines the limits of tension, and hence, torque.

2

Torque Measurements

Torque for mechanics is simply a twisting or turning motion around the axis of the thread. This resistance can be correlated to, but is not a direct measurement of, fastener tension. Generally, the higher the rotational resistance, the greater tension in the threaded fastener. In other words, the more effort it takes to tighten a bolt, the tighter it is.

Torque is measured as a unit of force acting on a rotating lever of some set length. In the bike industry and elsewhere, the common unit used to measure torque is the Newton meter (abbreviated Nm). One Newton meter is a force of one Newton on a one meter long lever. Another unit sometimes seen is the Kilogram-centimeter (abbreviated kgf-cm), which is a kilogram of force acting on a lever one centimeter long. It is possible to convert between the various systems.

Also sometimes used in the United States is the inch-pound (abbreviated in-lb.).This is a force of one pound acting at the end of a lever (wrench) that is one inch long. Another torque unit used in the USA is the foot-pound (abbreviated ft-lb.), which is the force in pounds along a one-foot long lever. It is possible to convert between the two units by multiplying or dividing by twelve. Because it can become confusing, it is best to stick to one designation. The units given on the torque table here will be in inch-pounds.

It is possible to convert between the various systems:

  • Nm = in-lb x 0.113
  • Nm = ft-lb x 1.356
  • Nm = kg-cm x 0.0981
3

Torque Wrench Types

Torque wrenches are simply tools for measuring resistance to rotation. There is a correlation between the tension in the bolt and the effort it takes to turn it. Any tool, even a torque wrench, should be used with common sense. A cross-threaded bolt will not properly tighten even with a torque wrench. The mechanic must be aware of the purpose of torque, and what torque and fastener preload are doing to the component joint. It is also important to consider thread preparation, which is discussed in detail in this article.


Beam Type

Park Tool doesn’t currently offer beam type torque wrenches (although our TW-1 and TW-2 torque wrenches are still in use by thousands of mechanics), but they are a common design. The beam design is relatively simple, and is accurate for both left-hand and right-hand threading. The socket head holds two steel beams, a primary beam and an indicator or pointer beam. The primary beam deflects as the handle is pulled. The separate pointer beam remains un-deflected, and the primary beam below flexes and moves with the handle. The reading is taken at the end of the pointer, at the reading plate on the primary beam. The handle is moved until the desired reading is attained. These wrenches rarely require re-calibration. If the pointer needle is not pointing to zero when the tool is at rest, it is simply bent back until it does align. Fatigue in the steel is not an issue.

Park Tool TW-1 in use on bicycle stem faceplate bolt
Beam-type torque wrench

Click Type

Park Tool offers two styles of “click” style torque wrenches. Both wrenches use 3/8″ square drive to accept standard 3/8″ bits.

The TW-5.2 has a range of 2Nm to 14Nm (18–124 inch-pounds). The TW-6.2 has a range of 10Nm to 60Nm (88–530 Inch Pounds).

The term “click type” can be misleading. This design of torque wrenches uses a swiveling head. There is a spring that is compressed by turning the handle. At higher settings the spring is compressed more which will allow the head to swivel only at higher resistance of higher torque. At high setting there is an audible “click” noise. But at lower setting there may be little or no noise as the head moves over as it swivels. The head swiveling indicates the resistance or torque has been reached, not the “click” noise.

TW-5.2 in use on bicycle stem bolt
Click-type torque wrench
4

Bicycle Torque Specifications

Below is a table of torque equivalents and formulas for conversions follow the torque table. The table is also available as a PDF file.

All figures in the table below are in Newton meters and inch-pounds. Note that some companies do not specify torque for certain components or parts. Contact the manufacturer for the most up to date specifications.

Wheel, Hub, Rear Cog Area

Component Type/Brand Newton Meters Inch-Pounds
Spoke tension Torque is typically not used in wheels. Spoke tension is measured by deflection. Contact rim manufacturer for specific tension recommendations. See TM-1.
Axle Quick-release: closed cam type Measured torque not typically used. Common industry practice is resistance at lever half way through swing from open to fully closed. For more see Tire and Tube Removal and Installation.
Solid axle nuts
(non-quick-release type wheels)
29.4Nm-44Nm 266–390
Cassette sprocket lockring Shimano® 29.4–49 260–434
SRAM® 40 354
Campagnolo® 50 442
Hub cone locking nut Bontrager® 17 150

Chris King®

12.2 100
Shimano® 9.8–24.5 87–217
Freehub body Bontrager® 45 400

Shimano®

35–50 305–434
Shimano® XTR w/ 14mm Hex 45–50 392–434

Headset, Handlebar, Seat and Seat Post Area

Component Type/Brand Newton Meters Inch-Pounds
Threaded headset locknut Chris King® Gripnut type 14.6–17 130–150
Tange-Seiki® 24.5 217
Stem binder bolt: Quill type for threaded headsets Shimano® 19.6–29.4 174–260
Generic brand range 16-18 144–168
Threadless stem steering column binder bolts Deda® 8 71
FSA® carbon 8.8 78
Syncros® cotter bolt type 10.1 90
Thomson® 5.4 48
Time® Monolink 5 48
Race Face® 6.2 55
Stem handlebar binder: 1 or 2 binder bolts Shimano® 19.6–29.4 174–260
Control Tech® 13.6–16.3 120–144
Stem handlebar binder: 4-bolt faceplate Control Tech® 13.6–16.3 120–144
Deda® magnesium 8 71
FSA® OS-115 carbon 8.8 78
Race Face® 6.2 55
Thomson® 5.4 48
Time® Monolink 6 53
MTB handlebar end extensions Cane Creek® 7.9 70
Control Tech® 16.3 144
Seat rail binder Shimano® 20–30 174–260
Campagnolo® 22 194
Control Tech® two-bolt type 16.3 144
Control Tech® one-bolt type 33.9 300
Syncros® 5 each bolt 44.2 each bolt
Time® Monolink 5 44.2
Truvativ® M8 bolt: 22–24
M6 bolt: 6–7.1
M8 bolt: 195–212
M6 bolt: 53–63
Seat post binder* Campagnolo® 4–6.8 36–60

*NOTE: Seat posts require only minimal tightening to not slip downward. Avoid over tightening.

Crankset, Bottom Bracket and Pedal Area

Component Type/Brand Newton Meters Inch-Pounds
Pedal into crank Shimano® 35 minimum 309.7 minimum
Campagnolo® 40 354
Ritchey® 34.7 307
Truvativ® 31.2–33.9 276–300
Compression slotted crank pinch bolts Shimano® Hollowtech® II 9.9–14.9 88–132
FSA® MegaExo™ 9.8–11.3 87–100
Crank adjusting cap Shimano® Hollowtech® II 0.5–0.7 4–6
FSA® MegaExo™ 0.5–0.7 4–6
Crank bolt (including spline-type cranks and square-spindle cranks) Shimano® 34–44 305–391
Shimano® Octalink® XTR® (M15 thread) 40.3–49 357–435
Campagnolo® 32–38 282–336
Campagnolo® Ultra-Torque® 42 371
FSA® M8 bolt 34–39 304–347
FSA® M14 steel 49–59 434–521
Race Face® 54 480
Syncros® 27 240
Truvativ ® ISIS Drive 43–47 384–420
Truvativ® square spindle 38–42 336–372
White Industries™ 27–34 240–300
Crank bolt one-key release cap Shimano® 5–6.8 44–60
Truvativ® 12–14 107–124
Chainring cassette to crankarm (lockring) Shimano® 50–70 443–620
Chainring bolt: steel Shimano® 7.9–10.7 70–95
Campagnolo® 8 71
Race Face® 11.3 100
Truvativ® 12.1–14 107–124
Chainring bolt: aluminum Shimano® 5–10 44–88.5
Campagnolo® 8 70.8
Truvativ® 8–9 70.8–79.6
Bottom bracket: cartridge type Shimano® 49.1–68.7 435–608
Shimano® Hollowtech® II 34.5–49.1 305–435
Campagnolo® (three-piece type) 70 612
Campagnolo® Ultra-Torque® cups 35 310
FSA® 39.2–49 347–434
Race Face® 47.5 420
Truvativ® 33.9–40.7 300–360
White Industries™ 27 240

Derailleur and Shift Lever Area

Component Type/Brand Newton Meters Inch-Pounds
Drop bar dual control brake/shift lever clamp bolt Shimano® STI™ 6–8 53–70
Campagnolo® 10 89
SRAM® 6–8 53–70
Shift lever: upright/flat bar type Shimano® STI™ 5–7.4 44–69
Shift lever: twist grip Shimano® Revoshift® 6–8 53–70
SRAM® 17 150
Shift lever: MTB “thumb type” Shimano® STI™ 2.4–3 22–26
Front derailleur clamp mount Campagnolo® 5 44
Campagnolo® 7 62
Shimano® 5–7 44–62
SRAM® 4.5 39.8
SRAM® 5–7 44–62
Front derailleur cable pinch bolt Shimano® 5-6.8 44–60
Campagnolo®5 44
Mavic® 5–7 44–62
SRAM® 4.5 40
Rear derailleur mounting bolt Shimano®

8–10

70–86
SRAM® 8–10 70–86
Campagnolo® 15 133
Rear derailleur cable pinch bolt Shimano® 5–7 44–60
SRAM® 4–5 35.4–44.2
Campagnolo® 6 53
Rear derailleur pulley wheel bolt Shimano® 2.9–3.9 27–34

Brake Caliper and Lever Area

Component Type/Brand Newton Meters Inch-Pounds
Upright bar brake levers Shimano® 6–8 53–69
Avid® 5–7 44–62
Campagnolo® 10 89
Brake caliper mount to frame:
side-pull, dual-pivot, center-pull
Shimano® 7.8–9.8 70–86
Campagnolo® 10 89
Cane Creek® 7.7–8.1 68–72
Tektro® 8–10 69–89
Brake caliper mount to frame:
linear-pull or cantilever
Shimano® 8–10 69–89
SRAM® 5–6.8 45–60
Avid® 4.9–6.9 43–61
Control Tech® 11.3–13.6 100–120
Tektro® 6–8 53–69
Brake pad:
threaded stud
Avid® 5.9–7.8 53–69
Campagnolo® 8 71
Cane Creek® 6.3–6.7 56–60
Tektro® 5–7 43–61
Shimano® 5–7 43–61
SRAM® 5.7–7.9 50–70
Brake pad:
smooth stud
Shimano® 7.9–8.8 70–78
Brake pad:
side-pull and dual-pivot bolts
Campagnolo® 8 72
Cane Creek® 6.3–6.7 56–60
Shimano® 6–8 53–69
Tektro® 5–7 43–61
Brake cable pinch bolt:
linear pull & cantilever
Control Tech® 4.5–6.8 40–60
Shimano® 6–7.8 53–69
SRAM® 5.6–7.9 50–70
Tektro® 6–8 53–69
Brake cable pinch bolt:
side pull/dual pivot/center pull
Campagnolo® 5 44
Cane Creek® 7.7–8.1 68–72
Mavic® 7–9 62–80
Shimano® 6–8 53–69
Tektro® 6–8 53–69

Disc Brake Systems

Component Type/Brand Newton Meters Inch-Pounds
Disc rotor to hub: lockring Avid® 40 350
Shimano® 40 350
Disc rotor to hub: M5 bolts Avid® 6.2 55
Hayes® 5.6 50
Magura® 3.8 34
Shimano® 2–4 18–35
Caliper body mount Avid® 9–10.2 80–90
Hayes® 12.4
9 with Manitou forks
110
80 with Manitou forks
Magura® 5.7 51
Shimano® 6–8 53–69
Tektro® 6–8 53–69
Hydraulic hose fittings Hayes® 6.2 55

Formulas for converting other torque designations into Newton meter (Nm) and inch pounds (in-lb.):

  • Nm = in-lb x 0.113
  • Nm = ft-lb x 1.356
  • Nm = kg-cm x 0.0981
  • in-lb = ft-lb x 12
  • in-lb = Nm x 8.851
  • in-lb = kgf-cm x 0.87

Torque Equivalencies

Newton meter (Nm)Approximate Inch-pound (in-lb.)Approximate foot-pound (ft-lbs)
1 8.9 0.7
2 17.7 1.5
3 26.6 2.2
4 35.4 3.0
5 44.3 3.7
6 53.1 4.4
7 62.0 5.2
8 70.8 5.9
9 79.7 6.6
10 88.5 7.4
11 97.4 8.1
12 106.2 8.9
13 115.1 9.6
14 123.9 10.3
15 132.8 11.1
16 141.6 11.8
17 150.5 12.5
18 159.3 13.3
19 168.2 14.0
20 177.0 14.8
21 185.9 15.5
22 194.7 16.2
23 203.6 17.0
24 212.4 17.7
25 221.3 18.4
26 230.1 19.2
27 239.0 19.9
28 247.8 20.7
29 256.7 21.4
30 265.5 22.1
31 274.4 22.9
32 283.2 23.6
33 292.1 24.3
34 300.9 25.1
35 309.8 25.8
36 318.6 26.6
37 327.5 27.3
38 336.3 28.0
39 345.2 28.8
40 354.0 29.5
41 362.9 30.2
42 371.7 31.0
43 380.6 31.7
44 389.4 32.5
45 398.3 33.2
46 407.1 33.9
47 416.0 34.7
48 424.8 35.4
49 433.7 36.1
50 442.6 36.9