How Your Vehicle Works

Rack & Pinion









Rack-and-pinion steering is quickly becoming the most common type of steering on cars, small trucks and SUVs. It is actually a pretty simple mechanism. A rack-and-pinion gearset is enclosed in a metal tube, with each end of the rack protruding from the tube. A rod, called a tie rod, connects to each end of the rack.

The pinion gear is attached to the steering shaft. When you turn the steering wheel, the gear spins, moving the rack. The tie rod at each end of the rack connects to the steering arm on the spindle.

The rack-and-pinion gearset does two things:

  • It converts the rotational motion of the steering wheel into the linear motion needed to turn the wheels.
  • It provides a gear reduction, making it easier to turn the wheels.
  • On most cars, it takes three to four complete revolutions of the steering wheel to make the wheels turn from lock to lock (from far left to far right).

    The steering ratio is the ratio of how far you turn the steering wheel to how far the wheels turn. For instance, if one complete revolution (360 degrees) of the steering wheel results in the wheels of the car turning 20 degrees, then the steering ratio is 360 divided by 20, or 18:1. A higher ratio means that you have to turn the steering wheel more to get the wheels to turn a given distance. However, less effort is required because of the higher gear ratio.

    Generally, lighter, sportier cars have lower steering ratios than larger cars and trucks. The lower ratio gives the steering a quicker response -- you don't have to turn the steering wheel as much to get the wheels to turn a given distance -- which is a desirable trait in sports cars. These smaller cars are light enough that even with the lower ratio, the effort required to turn the steering wheel is not excessive.

    Some cars have variable-ratio steering, which uses a rack-and-pinion gearset that has a different tooth pitch (number of teeth per inch) in the center than it has on the outside. This makes the car respond quickly when starting a turn (the rack is near the center), and also reduces effort near the wheel's turning limits.

    For expert car care and repair, "Don’t Worry… Call Auto Kruser's!"

    That's… Kruser with a 'K', Cool guys with a 'C'


    [Lots more information about vehicle steering]
    [Lots more information about gears]

    Complete
    Auto
    Service








    Under Hood: Air Conditioning Systems | Alternators & Starters | Automotive Batteries | Belts & Hoses
    Complete Engine Repair | Computerized Engine Diagnostics | Cooling System Repair & Service
    Electrical Systems | Emission Repair | Fuel System Injector Cleaning | Fuel Pumps & Lines
    Oil Change, Filters & Lube | Radiator Repair & Service | Scheduled Maintenance | Timing Belts & Chains
    Transmission Service & Repair | Tune Ups | Water Pumps

    Under Car: ABS Repair | Axle Repair | Brake Repair & Service | Catalytic Converters | CV Joints & Shafts
    Driveline Repair | Exhaust System Repair | Four-Wheel Drive Repair | Rack & Pinion
    Shock Absorbers & Struts | Springs | Steering & Chassis | Universal Joint | Wheel Bearings

    Exterior / Accessories: Electrical Accessories | Headlights | Power Window & Lock Repair
    Trailer Hitches | Windshield Wipers

    You Auto Know: Avoid Breakdowns |  Fuel Economy Tips |  Get the Most from Your Vehicle