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Your tyres in everyday use :

Michelin offers you advice and guidance so you can make the best use of your tyres, mile after mile...
               
  Your tyres in everyday use     Learn more about the tyre  
           
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Low tyre pressures - what happens

Low pressures affect the balance of the vehicle :


- A reduction in pressure on the front axle will tend to increase the chances of understeer.

- A reduction in pressure on the rear axle with tend to increase the chances of oversteer.

Understeer: The car turns less than expected Oversteer: The car turns more than expected

 

Low pressures and the effect on aquaplaning :


What effect does a reduction in pressure have on the amount of tyre in contact with the ground?
We conducted tests to see how much of the tyre is in contact with the ground when it was progressively deflated by driving a car through a flourescent die on a toughened glass window and photographed the results. As you can see below, the lower the pressure, the less tyre is in contact with the road.

If the tyre with correct pressures has a nominal surface contact area of 100%, then the progressive reduction in contact area can be seen.


VISUALISATION OF THE TYRE IN CONTACT WITH THE ROAD

Pressure = 2 bar
Surface contact= 100		 Pressure = 1,5 Bar
Surface contact = 50		 Pressure = 1 Bar 
Surface contact =  25

Low pressures and the effect on tyre life :


A tyre that is under inflated by 20% will have a reduction in life of just over 20% (depending on use)

Conversely, over-inflation will also increase the incidences of abnormal wear and these will be particularly accentuated in the middle of the tyre.
Low pressure and the effect on your fuel consumption:
 
A set of under inflated tyres will have the effect of causing the engine to work harder and this will increase your fuel consumption or decrease your fuel efficiency. A set of tyres that are 10psi under inflated will have the same effect as increasing the cost of fuel by 3p per litre. (based on £1.00 per litre)