We are excited to offer a 6 Speed AMC Sand Cast Aluminum Billet Gearbox for the Norton Commando racers and street bikes that produce more than 90 BHP. For the past 10 years, we have used the TTI gearbox in our Manx racers without a single failure!! All of the TTI gearboxes are manufactured in New Zealand and include the same expertise for the Norton Commando racers that we support. Bruce and the TTI team use a modern drum selector mechanism for a positive change with reduced pedal travel, stronger shafts & bigger bearings. We offer the "standard" AMC 5 Speed Gearbox that is built into sand cast aluminum alloy cases with numerous options as it is primarily used for racing. This gearbox can be offered with a kickstart shaft at an extra cost of $200 for the standard Norton kickstart lever. As a racer, you have a choice of “Manx or “Commando” length mainshafts based upon your application. (Note that the sprocket offset of the Commando configuration is 3mm further outboard) There is also an option for lever direction. Do understand that your actual pedal or linkage may be quite different from the drawing. Please take the time necessary to ensure your preference and specify it accurately. These gearboxes are built to your specifications.

TTI gearboxes use different final drive sprockets from other gearboxes and we do provide one sprocket with every gearbox. We offer the choice of 520 (1/4") or 530 (3/8") sprockets. The 530 sprockets are made to order and please advise when placing an order. Internal ratios are: 1st - 2.298:1, 2nd - 1.780, 3rd - 1.470, 4th - 1.260, 5th - 1.103 and 6th - 1.000. Additionally we recognize that some like options of a "taller" 1st gear to give a closer gearbox. However, in our experience, a taller 1st gear makes it more difficult to get off of the line and as a result, we recommend our 1st gear as it is closer to the standard Norton road 1st gear 2.556.

We do ship internationally and share our deep discounts with all of the major shipping services.