RcTek : Information & Resources for the Model Car Racer

Setting the Pinion & Spur Gear Gap Tip

This article is part of our Tips section, which aims to provide information regarding tips, tricks and modifications to a particular car or part, ones that don’t really warrant a specific article. The Technical Information section contains information regarding a wide range of subjects.

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Setting the Pinion & Spur Gear Gap

Setting the gap between gears

The gap between the pinion and spur gears on a radio controlled model car needs to be set correctly to allow the gears to work efficiently.
Too tight a gap can result in overheating and reduction of the cars speed due to the increased friction and/or premature bearing failure due to the increased load.
A gap that is too wide will lead to premature gear failure as there will not be sufficient strength in the area of the teeth that are contacting each other.

Setting the gap is most easily achieved by loosening the engine/motor and then placing a strip of paper (shown in red) between the pinion and spur gears. The engine should be tightened up with the gear pressing lightly against the paper. Rotating the gears will free the paper.

Please Note: The gap between the gear in the image on the right has been deliberately emphasized for clarity.

Due to the inaccuracies and clearances of some gear arrangements, two thicknesses of paper may be required.

For further information, please check our article about How Gears Work.

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