I am conducting a science experiment...?

Question

With my 2001 AWD Subaru Forester. The recommended tire pressure for the tires are 29 psi-Front, 28 psi-Rear.

What over or under inflation in psi should I have to experiment the effect of of inflating and deflating an automobile’s tires above and below the recommended levels on the increase/decrease of gasoline consumption in 20 miles per trial?

*I know the hazards, but I am still going to proceed. Thank you for your concerns though!

My question again: What psi should I have below and above the recommended levels for my experiment?

RECOMMENDED:

FRONT: 29 PSI

REAR: 28 PSI

Answer 1

I dont no what type of experiment you are trying but I would not suggest it, failure to maintain the correct air pressure can result in poor gas mileage, loss of tire life, bad handling, possible loss of control, and potential vehicle overloading.

Answer 2

i wouldn't go anymore than 5-10 over/under because the dangers would be more if you go higher than that.

7 would be a good number.  not low enough to blow out your tire or damage your rim.