This gauge works by measuring the distance between 2 lines scribed on the face of the tires. The difference between the front of the tires and the back of the tires is toe-in or toe-out. This should be done on a flat, level surface. Caster and camber should be set as should the chassis wheel weights.
- Connect the 2 longer tubes and tighten fasteners.
- Put 5/16” nuts included on threaded studs on the sliders and thread on pointers so they are pointing in the same direction and away from you as you read the scale. Tighten this nut. One slider has an oval opening with a groove in the center and must go at the end with the scale on the tube. The scale must be up.
Use gauge to measure toe-in
- You must first make a scribe line on the face of the tire. This must run true and indicates the plane of rotation. Anywhere on the face of the tire is OK. Lift each wheel to make this line. It can be done by 1 person but is easier with 2. To make the line hold a pointed object (a screw driver will work) against the tire and rotate the tire so as to leave a visible scribe line all around the tire. (See the Longacre catalog or online for our Billet Tire Scribe #79610. It has a spring loaded scribe tool that makes the job easy.)
- Once you have a scribe line on both tires roll the car back about 5’, then forward again. This simulates driving forward and takes the slack out of the suspension.
- On the slider/pointer with the slot move it until the groove in the middle of the opening lines up with the 0 on the scale. Tighten clamp (this may be a black knob or 2 hex bolts, depending on year model)
- Position the gauge under the car in front of the wheels with the pointers pointed up and back towards the tire. Move the entire tool so the tip of the pointer on the slider with the scale aligns with the scribe line of the tire.
- Go to the other end, loosen the clamp and move just the slider/pointer until it aligns with the scribe in the other tire. Tighten the clamp. Recheck the other end to be sure it is still aligned with the scribe line.
- Move the gauge to behind the wheels and position it the same for the front but with the pointers facing forward. Align the slider/pointer WITHOUT the scale with the scribe line. Go to the other end and see if the slider/pointer aligns with the scribe line. If it does you have 0 toe-in. If not loosen the clamp and move the slider/pointer until it aligns with the scribe line and tighten the clamp. Now read the toe-in or toe-out on the scale. If the reading is wider at the rear you have toe-in. If it is narrower you have toe-out.
- Adjust as needed. Each time you change the toe-in roll the car back, then forward again.