FAQ

Questions on the technical specs of all Peugeots

Torque measured from a car engine, what does it tell me?

Torque is the twisting force the engine applies to the crankshaft. In SI units, the power of the engine is measured as the torque times the rotational speed. A horsepower equals 550 foot-pounds per second. Two engines with very different torque characteristics can have exactly the same horsepower since one horsepower can be generated by moving one pound 550 feet or moving 550 pounds one foot, as long as it is accomplished in one second. The high torque engine would be rotating proportionally more slowly than the low torque engine at the same power output, but twisting the crankshaft harder.

How much drag is on your car?

When you are driving along at a constant speed, the power produced in the engine is converted to force at the tires. The drag force acts in the opposite direction and is equal to the force that the engine creates at the tires. Since these forces are equal and opposite, the net force on the car is zero, so the car maintains its constant speed. If you take away the force produced by the engine (by putting the car in neutral, for instance) then the only force on the car is the drag. Since there is a net force on the car, the car will begin to decelerate.

What does ESP stands for and why should you have it on your vehicle?

The electronic stability program (ESP) is a further enhancement to the anti-lock braking system (ABS) and traction control system (TCS). The ESP is designed to detect a difference between the driver's control inputs and the actual response of the vehicle. When differences are detected, the system intervenes by providing braking forces to the appropriate wheels to correct the path of the vehicle. This automatic reaction is engineered for improved vehicle stability, particularly during severe cornering and on low-friction road surfaces, by helping to reduce over-steering and under-steering.To implement ESP functionality, additional sensors must be added to the ABS system. A steering wheel angle sensor is used to detect driver input with a yaw rate sensor and a low-G sensor that measure the vehicle response. Some ESP systems include a connection to the powertrain controller of the vehicle to enable reductions in engine torque when required.

What do your tyre sizes mean? If your car is fitted with a set of 185-65HR13’s, what does it mean?

185 65 H R 13
This is the width in mm of the tyre from sidewall to sidewall when it's unstressed and you're looking at it head on (or top-down). This is known as the section width. This is the ratio of the height of the tyre sidewall, ( section height), expressed as a percentage of the width. It is known as the aspect ratio. In this case, 65% of 185mm is 120.25mm - the section height. This is the Speed Rating of the tyre. This tells you that the tyre is a radial construction. This is the diameter in inches of the rim of the wheel that the tyre has been designed to fit on. Don't ask me why tyre sizes mix imperial and metric measurements. They just do.

What does Lies and Speed ratings mean?

All tyres are rated with a speed letter. This will indicate the maximum speed that the tyre can sustain for a ten minute endurance without coming to pieces and destroying itself, your car, the car next to you and anyone else within a suitable radius at the time.

Speed Symbol Max Car Speed Capability Speed Symbol Max Car Speed Capability
Km/h MPH Km/h MPH
L 120 75 S 180 113
M 130 81 T 190 118
N 140 87 U 200 125
P 150 95 H 210 130
Q 160 100 V 240 150
R 170 105 W 270 168
  Z 240+ 150+

'H' rated tyres are becoming the most commonplace and widely used tyres, replacing 'S' and 'T' ratings.

Percentage-wise, the current split is something like this: S/T=67%, H=23%, V=8%.

Certain performance cars come with 'V' or 'Z' rated tyres as standard.

This is good because it matches the performance capability of the car, but bad because you need to remortgage your house to buy a new set of tyres.