RcTek : Information & Resources for the Model Car Racer

Model Car Differentials - The Adjustable Differential

This section of the RcTek site is devoted to differentials, what they are, what they do and the different types of that can be fitted to radio controlled model cars.

This brief article introduces one version of an adjustable differential that is fitted to some radio controlled model scale cars.

The Adjustable Differential

Adjustable Differential

As stated on the main section page, the term adjustable differential is somewhat of a misnomer as the majority of differentials have some degree of adjustability.

The adjustable differential we refer to in this article is a relatively simple derivative of the open differential. Although there are different designs and implementations they work by the same principle as the example used here.

The annexed illustration on the right shows a cross-sectional view of an adjustable differential that uses Belleville Washers to apply pressure to the sun gears to increase the resistance between the gears and therefore stiffen the action of the differential. Please note that this is not a real differential — it merely serves to demonstrate a principle.

As it is adjustable, the ‘diffing out’ associated with the open differential can be reduced or completely eradicated.

The adjustment is provided by a modified grub screw which allows quick and easy access for track side adjustments.

As far as the internal parts are concerned, they are the same ones that are fitted inside a normal open differential.

If not present on the non-adjustable type, steel thrust washers are fitted behind the the sun gears to stop the forces generated by the belleville washers wearing the casings.

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© 2001, 2009 by Darren Burnhill