How to use the toe gauge
Table of Contents
Toe-in and toe-out
In the wheel alignment, when the front wheel is viewed from above, the center of the tire is not completely facing straight ahead, but is slightly angled. The front side of the tire is closer than the rear side. As shown in the figure below, A (front side) is narrower than B (rear side). (A <B) Such a state is called toe-in, and conversely, a state where A side is wider than B (A> B) is called toe-out.
What is toin
A general vehicle is set in a toe-in state, and this value is said to be about 0 to 5 mm.
Role of toe-in
The role of the toe-in is, for example, when the vehicle is traveling straight, a force that always tries to move inward acts on one tire, and the two front wheel left and right tires try to move inward to each other. Is keeping. When the body tilts due to a crosswind or changes in road surface conditions, it naturally tries to move in the direction of the tilt, but if a toe-in is provided, it tilts due to the force that tries to maintain its straightness. A force that tries to counteract the force that tries to move in the right direction acts. As a result, the vehicle can travel straight ahead in a stable manner.
In this way, the toe-in plays an important role in the stable running of the automobile, and the toe-in gauge is a device that measures the difference in angle between the front side and the rear side of the front tires.
How to use the toe gauge
Toin gauge configuration
As shown in the figure above, the toe-in gauge has two pointers for measuring the tire width attached to a horizontally long bar, and consists of a fixing pointer on one side of the bar and an indicator (measurement reading) on the other side. There is. As shown in the figure below, the indicator section is equipped with a simple and sleeve mechanism similar to a micrometer.
How to read the scale of the indicator
Therefore, the bar has a structure that can be adjusted in length according to the width of the tread of the car body, one pointer is fixed with a wing nut along the center of the tire, and the other pointer is a thimble of the indicator part. It moves when turned, and the amount of movement is shown on the indicator.
The scale of the indicator part is designed so that the pointer moves 2 mm per rotation of the thimble. A scale is engraved on the sleeve in 1 mm increments, and a scale divided into 10 equal parts is engraved around the thimble. The minimum scale can be read up to 0.2 mm.
Toin gauge measurement method
The condition is that the place is flat and paved and the tire pressure is within the specified value.
- Put the front wheels straight
- Align the tip of the toe-in gauge pointer with the height of the center of the tire
How to align the pointer
- Mark the height of the center of the tire on the tread surface behind the left and right tires.
- Operate the micrometer on the indicator of the toe-in gauge to set the scale to zero. In that state, align the tip of the pointer with the mark.
- Gently advance the vehicle so that the measurement mark on the rear side of the tire is on the front side of the tire, and stop when the measurement mark (rotating the tire 180 degrees) reaches the center height on the front side of the tire.
Toe-in measurement procedure
- Align one pointer of the toe-in gauge with the measurement mark.
- For the other pointer, turn the thimble on the indicator to align it with the measurement mark. Read the scale of the micrometer section at that time. The value at that time is toe-in XX mm.
Toe-in measurement method
The toe-in adjustment is generally performed by rotating the tube at the tie rod end of the steering link gauge at the bottom of the suspension, although it varies slightly depending on the suspension type of the vehicle.
For independent suspension
Independent suspension type steering mechanism
Toe-in adjustment: Rack and pinion type
In the case of an independent suspension type rack and pinion type steering link, loosen the lock nut and turn the rack end as shown in the above figure.
In the case of ball nut type
Toe-in adjustment: ball nut type
For the ball nut type steering mechanism, loosen the clamp bolt and rotate the tie rod adjustment tube as shown in the figure.
In the case of rigid type
Toe-in adjustment: Rigid type
In the case of rigid axle type (axle type), loosen the clamp bolt and turn the tie rod.
In either case, the point is to rotate the left and right sides equally to distribute the adjustment dimensions, and if there is a difference between the left and right sides, the front wheel turning angle and the steering center position may be out of order.