Worn Shifting Dogs

[Stu Bloom]

Originally Posted by IrisLab

... Any engineering drawings available? Sketches? More importantly, equations!

Dave,

The TechnoKats/Andy Baker white paper (referenced above) is probably the best thing you will find to help explain this. If you still need any help with visualization please email me. I can try to put together some additional 3-d CAD views and/or animation of how this shifting arrangement works.

Good Luck!

[Andy Brockway]

We have not seen any wear after the three off-season competitions we ran with the square dogs. In fact the shifting seemed to get easier the more we ran the gearboxes. The square 'dog' is a nominal size, ie 1.25" square, while its mating hole is .004" larger, ie 1.254" square. This gives the needed clearance for the dog to fall into the hole. The corners do not mesh exactly, mostly clearance; the force is applied at a point similiar to a box wrench on a nut.

BTW we do not have any speed matching when we shift. The drivers pull a trigger to shift up and let go to shift down. Shifting down while running at high speed is not good for the gearbox just as it is not good for your father's car