Subject: Stuck Pedal Removal
From: Jobst Brandt
Date: March 12, 1999
What's the trick to removing pedals? Of the three times that I have tried to remove my pedals (I have two bikes and am in the process of exchanging/switching pedals) I have only succeeded once. The main problem is the pedals have been put on very tightly and I can't even budge the damn thing.
Left and right pedals have left and right threads respectively, and are best removed with a long handled 15 mm pedal wrench. Rather than using any clever wrench orientation or other methods to determine which way to tighten or loosen pedals, use the rule that rotating "forward" (as the wheels of the bicycle do) tightens and rotating "backward" loosens.
Pedals are often made with tight fitting threads in an effort to improve the hold of this poorly designed mechanical interface. The intent is to prevent relative motion under load although they move anyway. If that were not the case, the threads would not be left and right handed. That they move is also apparent from damage where the pedal axle frets against the crank face, the main causes of crank failures at the pedal eye. Besides damaging the crank face, fretting motion depletes thread lubrication and causes galling (aka welding) so that pedals often cannot be removed forcefully without damaging pedal shafts, wrenches, or cranks so that forceful removal strips threads.
To remove "frozen" pedals from an aluminum crank, remove the crank and pedal from the BB spindle, heat the pedal end of the crank over gas flame cooking stove until it sizzles to the wet touch. Using a pedal wrench, the pedal usually unscrews relatively easily without damage. If a lubricated pedal with clean threads does not screw in easily, a thread tap should be run through the crank to prevent galling on insertion. This is best done on the bicycle, where the crank is held firmly by the BB and prevented from rotation by the chain. To keep chain tension to a minimum (so the rear wheel does not spin), keep the pedal wrench as parallel to the crank as possible rather than as an extension to the crank.
Another trick to make it easier to turn the wrench is to tie the opposite crank to the bicycle frame (usually, the chainstay) with an old toe strap or a piece of rope. -- John Allen
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