Torque is the rotational equivalent of linear force. It describes the turning effect of a force applied at a distance from a rotation axis.

Formula: τ = r × F, where r is the distance and F is the force perpendicular to the radius.

• SI base: newton-meter (N⋅m)
• Imperial: pound-force foot (lbf⋅ft)
• Direction matters: clockwise or counterclockwise

Engine torque determines acceleration feel. Higher torque at low RPM means better pulling power.

Fastener torque specs prevent overtightening (stripping threads) or undertightening (loosening).

• Engine output: 100-500 N⋅m typical
• Wheel lug nuts: 80-140 N⋅m
• Precision: ±2-5% accuracy needed

Both use N⋅m dimensions but are different quantities!

Torque is a vector (has direction). Energy is scalar (no direction).

• Torque: rotational force at distance
• Energy (joules): work done moving through distance
• Don't use 'joules' for torque specifications!

Engine specs, lug nuts, and fasteners use N⋅m or lbf⋅ft depending on region.

• Engine output: 150-500 N⋅m
• Lug nuts: 80-140 N⋅m
• Spark plugs: 20-30 N⋅m

Industrial motors, wind turbines, and heavy equipment use kN⋅m or MN⋅m.

• Electric motors: 1-100 kN⋅m
• Wind turbines: MN⋅m range
• Excavators: hundreds of kN⋅m

Small devices use N⋅mm, N⋅cm, or ozf⋅in for delicate assembly.

• PCB screws: 0.1-0.5 N⋅m
• Smartphones: 0.05-0.15 N⋅m
• Optical equipment: gf⋅cm or ozf⋅in

Both use N⋅m dimensions, but torque and energy are TOTALLY different! Torque is rotational force (vector), energy is work done (scalar). Using 'joules' for torque is like calling speed 'meters' — technically wrong!

Diesel engines have 50-100% more torque than gas engines of the same size! A 2.0L diesel might make 400 N⋅m while a 2.0L gas makes 200 N⋅m. That's why diesels pull trailers better despite lower horsepower.

Electric motors deliver peak torque at 0 RPM! Gas engines need 2,000-4,000 RPM for peak torque. That's why EVs feel so quick off the line — full 400+ N⋅m instantly!

A 5 MW wind turbine generates 2-5 million N⋅m (MN⋅m) of torque at the rotor. That's like 2,000 car engines all spinning together — enough force to twist a building!

Bolts stretch when tightened. Overtightening by just 20% can permanently deform threads or snap the bolt! That's why torque specs exist — it's a Goldilocks zone.

Conrad Bahr invented the torque wrench to prevent over-tightening water pipes in NYC. Before this, plumbers just 'felt' tightness, causing constant leaks and breaks!

An engine making 300 N⋅m at 6,000 RPM produces 188 kW (252 HP). Same 300 N⋅m at 3,000 RPM = only 94 kW! High RPM converts torque to power.

A strong cyclist generates 40-50 N⋅m per pedal stroke. Tour de France riders can sustain 60+ N⋅m for hours. That's like continuously opening 4 stubborn jam jars simultaneously!

Isaac Newton defines force and rotational motion in Principia Mathematica, laying groundwork for torque concept

The term 'torque' first used in English by James Thomson (brother of Lord Kelvin) from Latin 'torquere' (to twist)

Conrad Bahr invents the torque wrench to prevent overtightening water pipes in New York City

Automotive industry standardizes torque specifications for engine assembly and fasteners

Newton-meter officially adopted as SI unit for torque (replacing kg⋅m)

Click-type torque wrenches become standard in professional mechanics, improving accuracy to ±3%

Digital torque wrenches with electronic sensors provide real-time readings and data logging

Electric vehicles showcase instant max torque delivery, changing how consumers understand torque vs power

Key factors for daily use

• 1 lbf⋅ft = 1.356 N⋅m
• 1 kgf⋅m = 9.807 N⋅m
• 1 N⋅m = 0.7376 lbf⋅ft

Best practices

• Store at lowest setting to maintain spring
• Calibrate annually or after 5,000 uses
• Pull handle smoothly, don't jerk

Relate torque to power

• Power (kW) = Torque (N⋅m) × RPM ÷ 9,550
• HP = Torque (lbf⋅ft) × RPM ÷ 5,252
• More torque at low RPM = better acceleration

Torque is rotational force (N⋅m or lbf⋅ft). Power is the rate of doing work (watts or HP). Power = Torque × RPM. High torque at low RPM gives good acceleration; high power at high RPM gives top speed.

No! While both use N⋅m dimensions, torque and energy are different physical quantities. Torque is a vector (has direction: clockwise/counterclockwise), energy is scalar. Always use N⋅m or lbf⋅ft for torque.

Check your car's manual. Typical ranges: Small cars 80-100 N⋅m (60-75 lbf⋅ft), Mid-size 100-120 N⋅m (75-90 lbf⋅ft), Trucks/SUVs 120-200 N⋅m (90-150 lbf⋅ft). Use torque wrench and star pattern!

Springs lose tension over time. After 5,000 cycles or annually, accuracy drifts from ±3% to ±10%+. Critical fasteners (engine, brakes, wheels) need proper torque — recalibrate professionally.

No! Overtightening strips threads or breaks bolts. Undertightening causes loosening. Follow exact specs. Torque is about precision, not maximum force.

Electric motors deliver peak torque at 0 RPM! Gas engines need 2,000-4,000 RPM for peak torque. A Tesla has 400+ N⋅m instantly, while a gas car builds to it gradually.