Zipper’s manufactures the strongest transmission door for Big Twin 5 speed transmissions.  This double row ball bearing design provides more shaft support than any other product on the market!

This door is the ideal choice for any high performance or hard core racing application.

These doors will give you:

  • Improved shifting
  • Less frictional losses
  • Added Support for durability in large power output applications

Machined from 6061 billet – available in either aluminum or black powder coated finish, includes double row bearings, spacers and shaft nuts for assembly.

Manufactured, with pride, in the USA!

Weight 1 lbs

Country of Origin

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Transmission Type

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