TORQUE and TORQUE WRENCHES

Threaded fasteners, like nuts and bolts, are held together by tension between the external and internal parts. Threads provide a continuously inclined plane, which creates a wedge for the bolt when torque is applied. This literally flexes the metal. The material attempts to returned to relaxed state, and this creates a tensile force (tension) that is the clamping force on the joint or fixture.

Torque, broadly stated, is simply a twisting or turning motion around the axis of the threaded fastener. Torque wrenches are basically tools for measuring resistance to rotation. This resistance can be correlated to, but is not a direct measurement of, fastener tension. Generally, the higher the resistance to rotation, the greater the tension in the threaded fastener.

Typically, lubrication is desired in the thread and at the bolt head. Without lubrication, a higher twisting resistance is felt by the torque wrench. The torque wrench reads only this resistance to rotation, it does not directly read the tension in the bolt. Consult the component/bicycle manufacturer for proper thread preparation if in doubt.

Cross threaded parts will cause more resistance than correctly aligned threads. A torque wrench is unable to distinguish this problem, it is the responsibility of the mechanic to note thread alignment.

It is important to comprehend torque unit specifications. For example, securing crank arms to 25 inch pounds is not the same as securing it to 25 foot pounds. Additionally, it is critical to understand when the torque wrench has achieved the dialed torque. "Click" type wrenches may not make an audible "click" when the torque is achieved. What occurs is a swivel in the head and a momentary change is the load. At low torques, the noise is nearly undetectable. In any case, a resonation is felt in the body of the wrench. Beam type wrenches are simply moved until the needle lines up with the correct reading.

The common cause for threaded fasteners loosening is simply that they were inadequately secured during initial assembly. Vibration, stress, or use/abuse can not typically overcome the amount of clamping force in a properly sized and secured threaded fastener.

Below is list of available bicycle specific torque specifications are given below. Some manufacturers do not specify torque for their product.

In the USA, the common unit used to measure torque is the inch-pound. In theory, this is a force of one pound acting at the end of a lever (wrench) only one inch long. Another unit is the foot-pound, 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. Park Tool torque wrenches are calibrated in inch-pounds.

Another unit of measure is the Newton-meter, which is a force of one Newton on a meter long lever. One side of the TW-3 and TW-4 shafts are graduated in Newton-meters.

All figures are inch-pound. Some companies do not specify torque for certain components or parts.

Component Shimano
in-lb.
Barnetts Manual Recommendation Other-
in-lb.
Hub cone locknut 87-217 120-180  
Axle nuts to frame 260-390 Front 180-240 Rear 240-300 Sachs 312
Control Tech 65 (steel)
Control Tech 85 (titanium)
Cassette lockring 260-434 265 Sachs 354
Campagnolo 442
Freehub body 305-434 310  
Headset locknut-threaded   300 Tange-Seiki 217
Chris King Gripnut type 130-150
Stem binder bolt- quill type 174-260 145-180 Control tech 144-168
MTB handle bar end extensions   120-145 Control Tech 144
Stem binder- threadless type   85-double bolt
100- single bolt
Control tech 120-144
Syncros cotter bolt type 90
"Grip Shift" mounting screw   20 Sachs 13-22
Handlebar binder 174-260 120-145 if 6mm thread
205-240 if greater than 6mm thread
Control Tech 120-144
STI type shift lever binder 53-69 50  
Shift lever- MTB "thumb type" 22-26 20-25  
Brake lever-MTB 53-69 35-60  
Brake lever-drop bar type 53-69 70-85 Sachs 88
Campagnolo 88
Pedal into crank 307 minimum 300-360 Ritchey 307
Campagnolo 354
XTR crankarm bolts 357-435    
Crankarm bolt 305-391 390 max. Sachs 336 max.
White Ind. 240-300
Syncros 240
Campagnolo 312-324
Chainring bolt- steel 70-95 50 Sachs 53
Campagnolo 84-120
Chainring bolt aluminum 44-88    
Bottom bracket
adjustable type
609-695 300- left lockring
360 fixed cup
 
Bottom bracket cartridge type 435-608 260-350 White Ind. 240
Real 432-612
Campagnolo 612
Front Derailleur clamp mount 44-60 40 Sachs 26-36
Campagnolo 61
Front derailleur cable pinch 44-60 35 Sachs 44-50
Campagnolo 44
Rear derailleur mounting bolt 70-86 70

Sachs 54-72

Campagnolo 133

Rear derailleur cable pinch bolt 35-52 35 Sachs 44-53
Campagnolo 53
Rear derailleur pulley wheel bolt 27-34 20- alloy Sachs 44-53
Brake mount to frame, side/dual/center pull 70-86 70-85 Cane Creek 72-84
Brake caliper mount to braze-on 44-60 25 Control Tech 100-120
Brake pad- threaded stud, cantilever or sidepull 53-69 50-60  
Brake pads smooth stud 70-78 70-80  
Brake cable pinch bolt- cantilever 53-69 50-70 Control Tech 40-60
Brake cable pinch bolt- sidepull/dual 53-69 50-70 Cane Creek 68-72
Brake arm pivot- dual pivot 70-86 50-70 Cane Creek 72-84
Sidepull/dual pivot brake pad bolt 44-60 50-70 Cane Creek 56-60
Cantilever straddle wire pinch 5x 0.8 thread 35-43 50-70 Control Tech 40-60
Brake caliper straddle wire pinch 6 x 1 thread 50-75 50-70  
Seat rail binder 174-347 120-145 single bolt
85-95 double bolt
Control Tech, 2 bolt type 144
Control Tech, single bolt 300
Syncros each 45
Seat post binder     Campagnolo 36-60
Spoke tension n/a n/a Spokes measured with tension, not torque at nipple. Contact rim manufacturer for specific tension recommendations
Quick release-closed cam type n/a n/a Measured torque not typically used. Common industry practice: resistance half way through swing

 

TORQUE EQUIVALENCIES

Inch pound
in-lb.

Approximate
Foot pound
ft-lbs

"Approximate Newton Meter Nm"

10"

.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"

 

Formulas for converting other torque designations into inch pounds (in-lb.).

in-lb. = ft-lb. 12
in-lb. = Nm 8.851
in-lb. = kgf-cm 1.15