Heel and toe
Heel and toe turns up in 2 fields: gears, automotive. Here is what it means to the people in each one.
Heel and toe in gears
The outer, wide end (heel) and inner, narrow end (toe) of a bevel or hypoid gear tooth.
On a bevel or hypoid gear, the heel is the end of the tooth farthest from the cone apex, at the outside diameter, and the toe is the end nearest the apex. Setup instructions describe the contact pattern by position along this length: a heel pattern or toe pattern means contact is concentrated toward that end. Under load the pattern moves toward the heel, so it is set slightly toward the toe when checked lightly loaded.
"Pattern's sitting on the heel on the drive side, bring backlash down a hair and it should walk toward the toe."
Heel-and-toe in automotive
A performance driving technique used to match engine speed while braking and downshifting.
A footwork method where a driver operates the brake and accelerator simultaneously with the right foot while clutching with the left. The driver rolls the side of their foot or pivots their heel to blip the throttle, matching engine revs to the lower gear. This prevents driveline shock and keeps the vehicle balanced during aggressive corner entry.
"You need to practice your heel-and-toe if you want to stop upsetting the chassis going into turn three."