The Effect of Tire Pressure on Stopping Distance

By: Dominic Corbett

Chevy Celebrity

The car being used to test is a 1987 Chevy Celebrity

It has 2 disk brakes and 2 drum brakes

There is no antilock brake system

All the tires have good tread

My Chevy Celebrity

How Brakes Work

Car brakes work by applying pressure to the decelerator pedal

This forces brake fluid to close calipers around rotors

The calipers rubbing on the rotors creates friction and eventually stops the tires

Purpose

To find if tire pressure really does effect stopping distance in fair weather conditions

This will show how important it is to check the tire pressure on your own car

Hypothesis

I believe that when the tire pressure is at the lowest it will stop the slowest.

The recommended tire pressure will probably stop the car the fastest.

Also having too much pressure in the tires will be dangerous and cause stopping distance to decrease

Materials

1987 Chevy Celebrity Tape measure Chalk Tape Air compressor Tire pressure gauge

Procedure

First inflate all tires to the same pressure

Mark a line on the pavement Next in a safe, closed, and

dry road bring the car to 20 mph

Put the car in neutral Once passing the tape jam

on the brakes as hard as possible till stopping

Mark where the front end stopped and measure from the stopping line

The Procedure

Data

Results

0

50

100

150

200

250

300

35 psi 30 psi 25 psi

Psi

Sto

pp

ing

Dis

tan

ce (

in)

Trial 1

Trial 2

Trial 3

Data cont.

35 psi 30 psi 25 psi

Trial 1 174 154 174

Trial 2 199 207 201

Trial 3 181 256 257185

Average 185 205 211

Conclusion

Overall the stopping distances were fairly close

The results matched the hypothesis One thing I noticed when testing the lower

pressure was that the tires would lock up and skid considerably further

Wheels Locking Up

Benefits of Checking Tire Pressure

Reduced stopping distances, Better handling of the vehicle in a curve or in

a lane change maneuver less chance of hydroplaning on a wet

surface, which effects both stopping distance loss of control.

Application

This applies to the real world by showing the effect of tire pressure on stopping distance

The relation to agriculture is through the machinery the machines have tires and if they are not inflated properly they create inefficiencies

Hopefully this shows how important it is to routinely check tire pressure