After a thorough ATV front end inspection I discovered I had a bent wheel and a bent left “A” arm. I replaced both front wheels and got the “A” arm bent back straight. Now its time to do an Utility ATV Front End Alignment in order to ensure my ATV goes in a straight line when I want it to.
The three factors that affect wheel alignment on an ATV are toe, camber and caster. The first two can easily be checked at home.
Toe is the fore-and-aft difference in tire distance. Some ATVs like my Polaris’s front tires are slightly bow-footed (toe-out), meaning the front of the wheels will angle away from the center of the ATV to intentionally place a very slight load on the wheel bearings. While other ATVs are slightly pigion-toed (toe-in). Typical toe-out and toe-in specs vary from 1/32” to 1/8”, depending on the ATV. Check your service manual for your ATV’s acceptable toe specifications.
Camber is the measurement of tire lean in degrees. If the top of the tire tilts inward, the vehicle has negative camber; outward lean is positive camber. Most ATVs will have a negative camber. The camber is not adjustable on a Polaris utility 4×4 ATV.
Caster is the angle of steering pivot in degrees. Just as water skiers lean backward for stability, most ATV’s are designed with a negative caster—the upper balljoint is to the rear of the lower balljoint (similar to the front wheels on a shopping cart). The caster is not adjustable on most ATVs
The process of a utility ATV front end alignment is not difficult but I do find it is necessary to have a second person to help. First off you will need to gather up some tools:
- Wrench Set (Specific to the ATV)
- 50” of String or Twine
- Push Pin
- 2 – Tie-Down Straps
- Tape Measure and marker
How I Preform A Utility ATV Front End Alignment:
Begin by positioning the ATV on a flat level surface and jack up the front end to a height just before the front tires leave the ground and set it on jack stands. (Setting the front end on jack stands is optional but provides a little more room to work).
- Using the tie-downs, strap the handlebars so they are held straight.
- Using the tape measure find the front center of the ATV and mark it with the marker.
- Tie the string around the push pin and on the left front tire push the push pin into a tire lug along the seam. True spec is measured midway up the tire even with the axle. See image to the right.
- Pull the string tight across the front of the ATV to the right front tire at the same height and with your thumb and fore finger mark the string where it intersects the tire seam on the right front tire. We will call this Measurement A.
- Keeping your thumb and fore finger marking the string at Measurement A, pull the push pin out of the left front tire and from the back of the right front tire slid the push pin with string under the ATV to the person helping you on the other side at the back of the left front tire.
- Have the other person push the push pin into a lug on the back of the left front tire along the seam midway up the tire or even with the bottom frame on the ATV.
- Pull the string tight underneath the ATV to the back of the right front tire at the same height referencing Measurement A on the string with your thumb and fore finger. Note where the string intersects the seam in the right tire, we call this Measurement B.
- On my Polaris Sportsman 700 X2 Measurement A should be 1/32” to 1/8” larger than Measurement B, but now Measurement A is 3/8” larger than Measurement B therefore the toe-out is too big by 1/4”.
- So I need to adjust one of the tie-rods. To determine which one, repeat step 4 and 5 but instead of pulling the string tight across the front of the ATV to the right front tire, pull the string tight to the center mark measured in step 3. Repeat this using the right front tire.
- Ideally these two measurements should be the same but now the measurement from the right front tire to center is larger than the measurement from the left front tire to center by about 1/4”. So the right tie-rod needs to be adjusted.
- The tie-rods link the steering stem to the hubs. The lengths of the tie-rods are adjustable via threaded ends into the balljoints.
- Using two wrenches (3/4” on the Polaris) I loosen the jam nuts on each end of the right tie-rod. One is standard and the other is reverse-threaded.
- There is a square edge about midpoint on the tie-rod allowing it to be turned with a wrench (3/8” wrench on the Polaris). I make small adjustments in the right tie-rod screwing it into the balljoints.
- I then repeat steps 4 – 9, readjusting the tie-rod if necessary until the correct toe-out is obtained. I recheck the measurements to the center mark on the ATV to verify they are the same. I tighten the jam nuts on the right tie-rod, again using two wrenches (3/4”).
Once you have done this procedure a couple of times you should be able to complete a utility ATV front end alignment in about 30 minutes at the most. When you ride fast and hard maintaining your ATV is a requirement that helps avoid mechanical failure and/or an accident.