Tech Tips

by Shawn Snyder

Copyright 2008-2009-2010 / ATVRE Media Group / www.atvre.com / All rights reserved

Caster & Camber

This month is about how to adjust your Caster, Camber. These are important adjustments to get  your ATV to handle properly.  You will need after market A-arms that are adjustable as most factory A-arms are not. There are also a lot of after market A-arms that will not allow you to adjust Caster, they have a fixed Caster.

Caster is the forward and rearward tilt of the top of the spindle over the bottom of the spindle. If the top of the spindle is tilted towards the rear of the ATV it is said to be positive Caster. If the top of the spindle is tilted towards the front of the ATV it is said to have negative Caster. You need positive caster to keep the wheels straight. When you have the caster and the tires axis inclination correct the wheel should run straight.

To adjust your caster you will need the following tools: First you have to start on a flat level surface. You will need a tape measure, steel  builders  square and an angle gauge. Put your ATV on level floor and make sure you check your tire pressure before you start with any adjustments make sure you set your ride height before you do any of these adjustments. I use weights to substitute the riders weight.

To start the adjustment of the ATV you make sure you seat the tires and suspension. The tires should push out and the shocks should be slightly compressed with rider’s weight on the ATV. You need to have the ATV consistent so your reading do not change. I also make sure the steering is fixed in the straight position, I use tie downs and fix them from the handle bars to the grab bar.

Next you can use an angle gauge or you can use a builder’s square, I use a 24” steel square and a tape measure. To use the angle gauge put it on the front straight part of the spindle or the sides of the ball joints. You may have to remove the brake caliper to do this as it makes it easier. The main objective is to find out the inclination of the ATVs spindle. We should have 5-7 degrees positive caster for motor cross. This setting can change for various tracks or conditions. I would use 5-7 degrees positive caster for cross country racing. I would use 3-5 degrees for sand dune riding. If you do not have a angle gauge, use can use builders square and tape measure.

Place the builders square against the lower ball joint.  Place the tape measure end on the side of the top ball joint and read to the edge of the square. You should have 5/8 “of positive caster. The top of the spindle will be tilted towards the rear of the ATV. To make this adjustment I loosen the inner hiems to adjust for caster. There are many different a arms but most

adjust with the inner hiems.

Camber is the tilt of the top of the spindle in or out over the bottom of the spindle. Positive camber is when the top of the spindle is tilted out away from the center of the ATV. You want to use 1-3 degrees negative camber for motocross and cross country. When measuring how much negative camber to use, the rider’s weight needs to be on the ATV. It also depends on how much wheel travel you have and the conditions and type of riding you will be doing. You want the most

contact of the tire tread on the ground. You also need to adjust camber before you adjust toe setting because it will change the toe.

To adjust your camber you can use an angle gauge or a builder’s square and tape measure. You can usually adjust your upper ball joint by moving the ball joint in or out.  Some a-arms have hiems ends on the end of the a-arms where they mount to the frame.  If you make an adjustment with the hiems ends move them evenly so you can not change your caster while adjusting your camber. I try not to adjust the camber at the hiems. If you have to much camber it makes it darty off the

jumps. To use the angle gauge I put a level flat against the rim and set the angle gauge on it and get a reading 1-3 degrees on the angle gauge. You also can use the steel square and tape measure. I place the square up against the tire, it should make contact at the bottom of the tire. You should have 1/2 - 5/8'' negative camber gap between the tire and the square. This is for cornering a lot like motor cross and cross country. I have had cross country guys ask for three

degrees camber often. You would usually run more negative camber on a hard packed track and less on a sand track or soft packed track.

Next month we will be discussing how to adjust the toe on your ATV. Thanks for reading my article, happy holidays and see you in the new year!

Thanks Shawn Snyder

Contact Shawn at email: snydermotorsports@earthlink.net