Tech Check: Shims

no wobble

Using Shims

Most chassis have some play out of the box or get some after some hours of use. Especially on the suspension at the inner and outer hinge pins play might occur.

For best performance and the most precise setup it is best to try to reduce play as much as possible. It is an easy, cheap and often overlooked way to upgrade the performance of any chassis.

In a few easy steps you can make your chassis wobble-free:

Step 1: Locate the Wobble

Identify the part which has too much play. In this example the suspension arms can slide too much forwards and backwards on the inner hinge pins.

Step 2: Find the Cure

Get the diameter of the part you want to shim and find shims of the right size. Some shims are offered as sets which contain several thicknesses of the same diamter.
measure measure

Step 3: Use It

Once you found the matching size, guess or measure how many shims of which thickness you might need. Disassemble the parts and put the shims on it. When you assemble again for a test, take care that the part assembles without any tension or pressure. If this is the case, remove one or more shims until you can mount the part without any problem.
measure

Step 4: Check

Once assembled, check if the part can move easily. In this example the suspension arm should lift and fall without jam. A minimal play should be kept to provide this easy movement.
Don't forgt to sometimes check if the parts move easily. If you drive on a clean race track, dirt is no problem. If you drive on a parking lot or off-road, it might be better to not reduce the play to an absolute minimum, but to keep it a bit looser to avoid the part get stuck by dirt.

Step 5: Watch the Movie

Same as written above in a small movie:

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