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The P512 gearbox is one of Xtrac’s legacy products, which whilst not currently in production, spares and technical support are still available upon request.

By adopting the basic “Racecar” gearbox layout and applying it to a Motorcycle cluster, Xtrac are able to offer a gearbox which is simple to work on and offers the ultimate in tuning of ratio selection.

With many years of Championships in the AMA Supercross and Motocross series, Xtrac has a wealth of experience to which they have utilised to produce this outstanding Moto GP gearbox.


  • 6 Gears selected sequentially by Selector Forks and Gear Change Barrel
  • Gearchange includes ratchet pawls, comb, plunger and torsion springs
  • Gear’s are 4 dog, hobbed and full form finished ground with 3.375mm high dogs mounted on double ended hubs
  • Selector Forks mounted on a Selector Rail, which is retained in the cluster plate by o-rings
  • 1st Gear integral with Layshaft. All other gears are slide on. The Cluster is on 68mm centres
  • Primary Gear pair driving the Clutch Basket
  • The Output Sprocket is mounted on the left hand end of the mainshaft
  • Shafts and Barrel supported on a Cluster Plate to fit casing
  • Lubrication is a common engine/gearbox system
  • Potentiometer Mounting and drive is included


  • Mainshaft gears supported on needle roller bearings
  • Gears can be full form ground
  • Low Inertia
  • Cluster cassette allow for easy maintenance and quick ratio changes
  • Improved shaft stiffness
  • Gear widths optimised in respect of tooth width depending on position and duty cycle
  • Gear dogs finish machine after heat treatment for improved dimensional accuracy
  • F1 style selector fork for weight and inertia optimisation

Options Summary

  • Ratio and Primary gear options available
  • Ultra-Lightweight gearchange barrel

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