How to adjust your caster on your a-arms

 

Caster is angle of the top ball joint or heim joint in relation to the bottom one. It has to be between a 4 and 5 degree angle (for MX). Here is what I did step by step to find the angle.

Step 1

First I took a motorcycle jack and put it under the quad to the height it is when I am sitting on it. Then I removed the front shocks.

Step 2

After I had the front shocks removed, I could then measure the angle where the joints are at. I used an old straight tie rod as my straight edge, a small level and a angle finder (contractors protractor).



I took the tie rod and ran it along the inside of the top and bottom heim threads. Then I took the angle finder
and ran it along side the tie rod. After I had those steps done, I had my friend hold the level on top of the angle finder until it was level. All of that gave me my angle of 11 degrees.



Step 3

It was originally at an 11 degree angle which was way off from where it was supposed to be, so I knew I found the reason it was handling so bad.

So I took the top a-arm off on the side that it is mounted to the frame.



Once I had it off, I screwed both of the heim's all of the way in as far as they would go and still mount up to the frame.

Then I started turning the back heim out. Janssen's website said to start with three turns and go from there so that is what I did. I mounted it back up and measured the angle again (STEP 2 Pic 2). it was still too much of an angle so i turned it out 3 more times for a total of six full turns.



So I mounted it back to the frame once again and measured it and it came out to be exactly 4.5 degrees.



Once all of that is done, move on to the next side and repeat the steps. After both sides are set at the proper angle you will need to set the toe of the tires and the camber. the tires should be toed in between 1/8 and 1/4 inch.

To adjust the camber you use the same method for finding the angle of the tire as you do for finding the angle of the heims. set the tie rod on the out side of the tire, run the angle finder along it and then use the level to find the angle. You the adjust the top large heim in or out untill it gets the wheel to the angle that is desired. it needs to be a 4 degree angle as well (for MX).



Once all three things are set put the shocks back on, take it off of the stand and your ready to ride.



I hope this is easy to understand for everyone. I had no idea how much better the quad would handle with the caster set right. It was a night and day difference. So if you have never done this or did not do it right i would suggest doing it because it will make riding a lot more fun and it will be easier to ride. you wont have to make it turn anymore it will trun easily on its own, and turn on a dime.

Also here a link to Jannsens website. it gives you all of the angles for caster and camber for different styles of riding like Motocross, Cross Country, Sand Dunning, Desert Racing and Recreational Riding. It will also give you some other useful info for setting up the front end of your quad...

http://www.janssenmotorsports.com/tech_articles.php?act=getonearticle&artid=9