Joined: May 2010
Posts: 591
Likes: 1
From: Bucharest, Romania, Europe
Bikes: 1989 Krapf (with Dura-ace) road bike, 1973 Sputnik (made by XB3) road bike , 1961 Peugeot fixed gear, 2010 Trek 4400
A shop use pedal wrench is about 300mm long (about a foot).
Also, never push the wrench, but pull it! When it gets loose you would encounter a sudden twist on great angle. If you push it, your fingers/hand might hit the chainstay, chain, the crank itself, etc. It almost always rip some skin away. Always pull on wrenches and never push.