APE TRANSMISSIONS

Transmission Undercutting

Undercutting a transmission involves machining angles on the engagement dogs and slots to prevent the transmission from jumping out of gear under load. There are three types of undercuts available from APE

Racecut...
This cut is performed on the side of the dogs that are loaded on acceleration. Recommended for hot street bikes and drag racers, dwarf cars, etc.

Up and down cut....
Both sides of the dog are cut to also prevent jumping out of gear on down shifts. Recommended for road racing.

Under cutting notes... Some of the newer sportbikes are coming from the factory with undercut gears in the transmission. When you send us your trans, if it has factory undercut that is adequate, you will not be charged for undercutting that gear or gears.
If dogs are rounded off due to repeatedly slipping out of gear of missed shifts, they can not be undercut. You will be notified by APE tech staff if any of your trans parts are unusable.

There are times when small things like clips and spacers are unusable. These parts will be replaced at a nominal charge when servicing transmissions.

We also operate a complete aerospace-type CNC machining facility in which we manufacture our world-famous racing products. These facilities are all on-site at the APE race shop. Besides the services listed below, APE also offers:

Complete Machine Work Service
Crankshaft Service
Cylinder Head Service

Call APE to place a transmission work order. (661) 256-7309

Please read our shipping instructions carefully.

Include an APE work order form when sending parts for labor.

Ship parts to:
APE
7347 Rosamond Bl.
Rosamond, Ca. 93560

What exactly is undercutting?

The transmission gears lock together with a series of "dogs' or "dogs and slots" The photo below shows several of the dogs engaged together so that both gears turn together. Under hard use, the gears can began to separate until the dogs become disengaged, this causes the transmission to jump out of gear.

Now notice in the above photo the dogs that are in the circle. They both have angles cut on them where they meet. This causes them to lock together. They cannot separate without first backing up to unload the angles. This is an undercut. On APE transmissions, all of the dogs get these precise angle cuts.

Road race "up and down" cuts have angles machined on both sides of the dog so it works the same way under acceleration load and deceleration load.