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 |
Approximate |
"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