Tire pressure and mpg

[DaveS]

So I have been getting some pretty bad mileage lately - last tank was 17.8L/100km which is around 13mpg. The reading on the computer was around 15.5L/100km - usually level of error.

Saturday I go out and look at the tires - they look a bit low I think and check the pressure - 26PSI!! (on winter tires right now so no TPMS and so cold I have not been rushing to check by hand).

Pump them up to 32PSI, gas up and reset the computer - now its showing around 12.3L/100km. That will probably be around 14L/100km i e around 17mpg. Last time I leave it so long before checking....

 

[ToyotaDoodz]

Gas mileage is the least of your worries. Running at low PSI will cause heat to build up inside the tire which can cause belts to separate and premature tire failure. Tire pressure is very important and often over looked.

Do you know if they've been that way very long (many miles)?

 

[DaveS]

Not sure - they went on in November - my guess is they were installed in the nice warm service area then they went outside and the pressure dropped on them in the cold. Probably 1000 miles on them so far and nothing to speak of on the highway - I think the pressures have fallen on them fairly recently with the extreme cold we have had the past few weeks - I would have noticed them looking low before otherwise I think. Just wish these winters had the TPMS in them - steel rims..

 

[ToyotaDoodz]

Since it wasn't much highway you're probably OK.