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Hostile Racing Products is proud to offer optional gearing ratios using lightweight and durable plastic spur gears.

All other current gearing options use heavy and expensive steel spur gears. By using our high quality and super strong material, we are able to offer spur gears at a fraction of the weight and cost of steel

These high quality injection molded gears are offered in the stock 17/57 gear set as well as higher speed sets such as 18/56, 19/55 and 20/54.

Hostile spurs offer:

1. Harder material for longer life and less wear.
2. Higher strength material to reduce gear failure
3. Handles higher temperatures
4. Lightweight and economical alternative to steel
5. Available in several sizes for a variety of gearing options
6. Made in the USA

The fixed gear mesh on the HPI system uses a total number of 74 teeth when using perfect tooth profiles. To change gearing and maintain perfect tooth profiles the pinion must be changed with the corresponding spur to total 74 teeth. For example: 17/57, 18/56, 19/55 and so on... For convenience, HPI chose to offer pinions of 16, 17 and 18 while still using the 57 tooth spur gear. The 17 being the proper gear to mate with the 57, meant that they would need to modify or deviate the tooth profile of the 16 and 18 tooth pinion to still create the same diameter and proper mesh. This deviation of 1 tooth either way is still within reasonable tolerances to be functional and convenient. It does however require the tooth profile deviate from the perfect shape and does have some drawbacks.

-Our 57 tooth spur is for use with:

HPI 16, 17 and 18 tooth pinion

Robinson, Turtle, Hostile, DDM, Vertigo 17 tooth pinion


-Our 56 tooth spur is for use with:

Robinson, Turtle, Hostile, DDM and Vertigo 18 tooth pinion


-Our 55 tooth spur is for use with:

Hostile, DDM, Vertigo and Turtle 19 tooth pinion (mesh is loose with Turtle 19)


-Our 54 tooth spur gear is for use with:

Turtle, DDM and Vertigo 20 tooth pinions