The go kart was driving fine or so it seemed until the steering wheel started to wobble heavily. “Man!” exclaimed the youth as he pulled into the pit stop, “ I just replaced the rod ends and it’s still shaking. I should have not bought this used go kart what a piece of junk!”
Is this go kart a piece of junk? Should I stop writing this article right now? Are all go karts just junk waiting to be thrown away anyway?
What would make me as such a dumb questions? Or are they reasonable?
Remember in our go kart builders mindset one of the points about a go kart builder is that he understands that things do go wrong and that everything is an opportunity when it does go wrong. So what went wrong and what can be learned from this?
When you encounter a problem one of the major elements in troubleshooting is identifying what the variables are in the system. In the steering system there are three major components:
– The guide to the the main steering shaft and associated bearings
– the tie rod ends
– the steering knuckles
– and on the wheel bearings/wheel adjustment
– and the steering wheel mounting/main steering shaft interface
(Hey, that’s more than three! Just hold your horses, read on…!)
For the most part the steering wheel and the main steering shaft support bearings are relatively tight until you can discount those as being the major problem areas: so the system is reduced down to the three: the rod ends, the steering knuckles and the wheel bearing/wheel adjustment.
In the article on rod ends we identifying that the rod ends can be a culprit in steering vibration. As the driver indicated the rod ends have been replaced and tightened up. So the driver had apparently thought that the rod ends were the only problem. But alas “grasshopper” there is another problem area and it could be one of the two: the wheel bearings will or the steering knuckles.
In this instance actually it was the steering knuckles.
Very often the steering knuckles system will include a plastic shim which is put in the pivot section to make up the slop. There are really three reasons for using the plastic pushing: first the plastic bushing is cheap, second the plastic bushing can be replaced and the third is that the tube is a standard off-the-shelf tube.
What occurs on older go kart is that the plastic bushings become wallowed out or destroyed. The steering system therefore becomes more sloppy and vibration can result into the steering system. The best way to keep vibration to a minimum in the steering system is to make sure everything is tight. Also it helps obviously, to have the wheels balanced, that is a secondary cause to vibration.
Sometimes the plastic bushings cannot be purchased so the go karters are left with either dealing with the vibration, or making a substitute bushing. A substitute bushing can be readily made using sheet-metal that is inserted like a collar into the pivot tube.
Typical sheet-metal used in the duct work is applicable. Sometimes however the clearance is not sufficient for the sheet-metal is too thick. An alternate material would be to use shim stock sold at local hardware stores. The shim stock is wrapped around the pivot bolt and then inserted into the pivot tube.
So the next time you run into sloppy steering systems or you are developing your own steering system but don’t want so much slop: consider the sheet-metal shim method.