H-Pattern Gear Sets: Synchro / Dog Box 

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Gear Tooth Profiles: Straight Cut / Helical Cut 

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H-Pattern gear sets is where it all began for PPG, faced with the need for performance gear sets to replace OEM gear sets for high performance cars,

Simon Pfitzner (MD) and his then business partner soon realised their was an opportunity to manufacture and supply this growing marketplace with high performance gears . 

 

Soon after PPG was born and as they say, "the rest is history".....

 

H-Pattern gearboxes in road cars come as Synchromesh helical tooth designs from the factory, this enables smooth changes and quiet operation in use and usually lasts the life time of the car.

 

However since cars have been raced back in the early 1940's their has been a requirement for gearboxes to shift faster than synchromesh could allow without damage being caused.  The product that evolved for racing was referred to as a "Dog Box". 

 

A "Dog Box" is usually a Dog Engagement type arrangement and thus eliminating the synchromesh system standard cars use for smooth gear changes. 

 

The dog engagement has its history in old agricultural type machinery and required a fair degree of mechanical sympathy to change smoothly.

 

The speed of operation is not limited unlike the synchromesh system they replace, making them ideal for motorsports application.