Chevrolet Sonic Repair Manual: Scrub Radius Description
Ideally, the scrub radius is as small as possible. Normally, the SAI angle and the centerline of the tire and the wheel intersect below the road surface, causing a positive scrub radius. With struts, the SAI angle is much larger than the long arm/short arm type of suspension. This allows the SAI angle to intersect the camber angle above the road surface, forming a negative scrub radius. The smaller the scrub radius, the better the directional stability. Installing aftermarket wheels that have additional offset will dramatically increase the scrub radius. The newly installed wheels may cause the centerline of the tires to move further away from the spindle. This will increase the scrub radius.
A large amount of scrub radius can cause severe shimmy after hitting a bump. Four-wheel drive vehicles with large tires use a steering damper to compensate for an increased scrub radius. Scrub radius is not directly measurable by the conventional methods. Scrub radius is projected geometrically by engineers during the design phase of the suspension.
Replacement Wheels Description
Replace the wheel if any of the following conditions exist:
The wheel exhibits excessive runout.
The wheel is bent.
The wheel is cracked.
The wheel is severely rusted.
The wheel is severe ...
Spare Tire Kit Installation
Installation Instructions Part Number
95280943
Procedure
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Other materials:
Sunroof Window Height and Opening Fit Adjustment
Note: Correct adjustment cannot be achieved if the sunroof window
is closed from vent position.
Cycle the sunroof window from full open to closed position.
.,
Note: Do Not remove or lower headliner to access sunroof window
screws.
Loosen the adjusting screws on ...
Engine Coolant Thermostat Installation
Caution: Refer to Engine Coolant Thermostat Housing Caution.
Clean the engine coolant sealing surfaces.
Install the engine coolant seal (1).
Install the engine coolant thermostat assembly (2).
Caution: Refer to Fastener Caution.
Install the 4R ...
Spark Plug Inspection
Spark Plug Usage
Ensure that the correct spark plug is installed. An
incorrect spark plug causes driveability conditions.
Ensure that the spark plug has the correct heat range.
An incorrect heat range causes the following conditions:
Spark plug fouling?older plug
...
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