How To Remove and Install Basic Bicycle Pedals 

Just so that it's clear for everyone, the drive side (right side) threads normally, Lefty Loosey Counter Clockwise, Righty Tidey Clockwise. The non-drive side (left side) is the opposite, to the left tighten C-Cl, and to the right loosens Cl.

Some pedals are actually 9/16".... Which is around 14.2mm. So a 14mm wrench won't fit, but a common 15mm pedal wrench will work somewhat okay, and most people don't even know it's a 9/16" and not 15mm. If you frequently remove pedals often, they'll start to round-off the pedal spindle using a 15mm pedal wrench. Even most bike shop mechanics are even clueless and don't realize a 5/16" pedal size exists, happily just using their 15mm wrench because it works on most all new pedals.