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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. The Bicycle Specific Torque Values is available as an Adobe Acrobat PDF file.

Threaded fasteners (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 (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) as it holds the arm in place.

It is commonly believed that bolts and nuts often come loose 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.

 

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 USA, the common unit used to measure torque is the inch-pound (abbreviated in-lb.). This is a force of one pound acting at the end of a lever (wrench) only 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 the in-lb.

A more universally accepted torque measurement is the Newton-meter (abbreviated Nm). One Newton-meter is a force of one Newton on a meter long lever. Another option sometimes used 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.

in-lb = ft-lb. × 12   EXAMPLE: 5.5 ft-lb × 12 = 66 in-lb
in-lb = Nm × 8.851   EXAMPLE: 9 Nm × 8.851 = 79.7 in-lb
in-lb = kgf-cm × 0.87   EXAMPLE: 300 kgf-cm × 0.87 = 261 in-lb

 

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 doing to the component joint. It is also important to consider thread preparation, which is discussed in detail at the end of this article.

Torque wrenches available to general industrial work, including bicycle work, are typically accurate to plus or minus four percent. In other words, a torque wrench set for 100 in-lbs might tighten to 96 in-lbs, or 104 in-lbs. There are basically three types of torque wrenches, the beam type, the click type and the dial type. The click type and dial type wrenches have more moving parts than the beam, and are susceptible to wear and will require re-calibration. The bicycle has relatively light torque specifications (20-inch pound) to relatively heavy torque specifications (600 inch-pound). There is no single torque wrench accurate for this wide range. Consequently, Park Tool offers two different wrenches.

 

Beam Type

Park Tool TW-1, and TW-2 torque wrenches are beam-type. 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.

Take the reading at the end of the pointer   Hold handle to neither end touches tool

Beam Type Torque Wrench Calibration

It is possible for any torque wrench to come out of calibration. The beam type wrenches use a simple principle of deflection that allows the user to re-calibrate the wrench. Inspect the pointer when the wrench is at rest. If it is pointing to zero on the scale, the wrench is calibrated. If the pointer is off to either side, the pointer beam can be bent back so it again points at zero. It is easiest to use a lever between the two beams and pry small amounts, checking the scale and the pointer often.


Re-calibration of the beam type wrench.

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 HERE.

All figures in the table below are inch-pound. 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
Shimano®
in-lb.
Other-
in-lb.
Spoke tension Torque is typically not used in wheels. Spokes tension is measured by deflection. Contact rim manufacturer for specific tension recommendations. See TM-1
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.
Axle nuts to frame
(non-quick release type wheels)
260-390 Control Tech® 65 (steel)
Control Tech® 85 (titanium)
SRAM® 266-350
Cassette sprocket lockring 260-434 Campagnolo® 442
SRAM® 310-350
Hub cone locking nut 87-217 Bontrager® 150
Chris Kingreg; 100
Freehub body 305-434 Bontrager® 400
Headset, Handlebar,
Seat and Seat Post Area
Component
Shimano®
in-lb.
Other-
in-lb.
Threaded headset
locknut
  Chris King® Gripnut type 130-150
Tange-Seiki® 217
Stem binder bolt- quill type for threaded headsets 174-260 Control Tech® 144-168
Stem steering column binder bolts
Threadless headset types
  Control Tech® 120-144
Deda 71
FSA® carbon 78
Syncros® cotter bolt type 90
Thomson® 48
Time® Monolink 45
Stem handlebar binder
1 or 2 binder bolts
174-260 Control Tech® 120-144
Stem handlebar binder
4 binder bolts
  Control Tech® 120-144
Deda magnesium 71
Thomson® 48
FSA® OS-115 carbon 78
Time® Monolink 53
MTB handle bar end extensions   Cane Creek® 70
Control Tech® 144
Seat rail binder 174-347 Control Tech®, 2 bolt type 144
Control Tech®, single bolt 300
Syncros® each 45
Time® Monolink-44
Travativ® (M8 bolt) 195-212 / 53-63 ( M6 bolt)
Seat post binder
Note: Seat posts require only minimal tightening to not slip downward. Avoid over tightening.
  Campagnolo® 36-60
Crankset, Bottom Bracket and Pedal Area
Component
Shimano®
in-lb.
Other-
in-lb.
Pedal into crank 307 minimum Campagnolo® 354
Ritchey® 307
Truvativ® 276-300
Shimano® Octalink XTR crankarm bolts (M15 thread) (not Hollowtech II) 357-435  
Shimano® Hollowtech II bottom bracket bearing cup (2004 XTR, XT, Dura-Ace) 305-435  
Shimano® Hollowtech II crank bolt screws (2004 XTR, Dura-Ace, XT) 88-132  
Shimano® Hollowtech II
Left-hand fixing cap
4-6  
Crank bolt (including spline-type cranks and square-spindle cranks) 305-391 Bontrager® 310-380
Campagnolo®312-324
FRA® (M8 bolt) 304-347
FRA® (M14 steel) 434-521
Race Face® 480
Syncros®240
Truvativ® 384-420 ISIS Drive
Truvativ® 336-372 square type White Ind® 240-300
Crank bolt one-key release cap 44-60 Truvativ® 107-124
Chainring cassette to crankarm (lockring) 443-620  
Chainring bolt- steel 70-95 Campagnolo® 84-120
Race Face&erg; 100
Truvativ® 107-124
Chainring bolt aluminum 44-88 Truvativ® 72-80
Bottom bracket
adjustable type
609-695  
Bottom bracket cartridge type 435-608 White Ind.® 240
Real 432-612
Campagnolo® 612
FSA® 347-434
Race Face® 420
Truvativ® 300-360
Derailleur and Shift Lever Area
Component
Shimano®
in-lb.
Other-
in-lb.
STI type shift lever binder 53-69  
Shift lever- MTB "thumb type" 22-26  
Shift lever- "twist grip" type "Revo" shifter 53-70 SRAM® 17
Front Derailleur clamp mount 44-60 Campagnolo® 61
Mavic® 26-35
SRAM® 44-60
Front derailleur cable pinch 44-60 Campagnolo® 44
Mavic® 44-62
SRAM® 40
Rear derailleur mounting bolt 70-86 SRAM® 70-85
Campagnolo® 133

 

Rear derailleur cable inch bolt 35 Campagnolo® 53
SRAM® 35-45
Rear derailleur pulley wheel bolt 27-34 Sachs® 44-53
Brake Caliper and Lever Area
Component
Shimano®
in-lb.
Other-
in-lb.
Brake caliper mount to frame, side/dual/center pull 70-85 Campagnolo® 90
Cane Creek® 68-72
Brake caliper mount to braze-on
linear pull/cantilever
44-60 Avid® 43-61
Control Tech® 100-120
SRAM&erg; 45-60
Brake pad- threaded stud, dual pivot/cantilever/sidepull 44-60 Avid® 52-69
Cane Creek® 56-60
Campagnolo® 72
Mavic® 62-80
SRAM® 50-70
Brake pad- smooth stud, cantilever 70-78  
Brake cable pinch bolt- linear pull/cantilever 53-69 Control Tech® 40-60
SRAM® 50-70
Brake cable pinch bolt-sidepull/dual pivot/centerpull 53-69 Campagnolo® 45
Cane Creek® 68-72
Mavic® 62-80
Brake caliper arm pivot- dual pivot 70-86 Cane Creek® 72-84
Sidepull/dual pivot brake pad bolt 44-60 Cane Creek® 56-60
Cantilever straddle wire pinch 5 x 0.8 thread 35-43 Control Tech® 40-60
Brake caliper wire pinch
linear pull/cantilever
M6 x 1 thread
50-75 Avid® 52-69
Brake lever-MTB type 53-69 Avid® 40-60 (clamping built into body)
Avid® strap type 28-36
Cane Creek® 53-80
SRAM® 30
Brake lever-drop bar type
(including STI and Ero types)
53-69 Campagnolo® 88
Mavic® 62-80
Disc Brake Systems
Component Shimano®
in-lb.
Other-
in-lb.
Disc rotor to hub 18-35 (M5 bolts)
350 (M965 rotor locking)
Hayes® 50
Avid®-55
Magura®-34
Caliper mount 53-69 Avid® 80-90
Magura® 51
Hydraulic hose fittings 44-60 Hayes® 55

 

Formulas for converting other torque designations into Netwon 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 × 12

in-lb = Nm × 8.851

in-lb = kgf-cm x 0.87

 

Torque Equivalencies

Inch pound
in-lb.

Approximate
Foot pound
ft-lbs

Approximate Newton Meter
Nm

10

0.8

1.1

20

1.7

2.3

30

2.5

3.4

40

3.3

4.5

50

4.2

5.6

60

5.0

6.8

70

5.8

7.9

80

6.7

9.0

90

7.5

10.2

100

8.3

11.3

110

9.2

12.4

120

10.0

13.6

130

10.8

14.7

140

11.7

15.8

150

12.5

16.9

160

13.3

18.1

170

14.2

19.2

180

15.0

20.3

190

15.8

21.5

200

16.7

22.6

210

17.5

23.7

220

18.3

24.9

230

19.2

26.0

240

20.0

27.1

250

20.8

28.2

260

21.7

29.4

270

22.5

30.5

280

23.3

31.6

290

24.2

32.8

300

25.0

33.9

310

25.8

35.0

320

26.7

36.2

330

27.5

37.3

340

28.3

38.4

350

29.2

39.5

360

30.0

40.7

370

30.8

41.8

380

31.7

42.9

390

32.5

44.1

400

33.3

45.2

410

34.2

46.3

420

35.0

47.5

430

35.8

48.6

440

36.7

49.7

450

37.5

50.8