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I'm sure this question must have already been answered somewhere here, but it doesn't show up in any search results I make...

I'm changing the pedals on a 40 year old bike. Pretty sure the pedals are original. The left one came off fine. Unfortunately, I got the thread directions mixed up and tightened the right one by mistake!

Now the right pedal won't come off at all. When I apply force to the pedal wrench (in the correct, counter-clockwise direction), the crank just backs up, and the pedal doesn't budge.

I have two questions:

  • Short of making the trek to my LBS (which is a little out of the way) what are some ways I could try to get the pedal unstuck?

  • Is there some way to immobilise the crank? I don't think I have the tools necessary to take the arm off the bike.

Things already tried:

  • Penetrating oil in the screw.
  • Hammering the wrench.

Things I don't have the equipment for:

  • Heating the screw.
  • Lengthening the wrench.

EDIT: An additional note: It seems the reason the pedal wouldn't come out is that there's something wrong with the threads on the crank. I can't get the old or my new pedal to go in past the second turn. Going to have to take it to the LBS anyway...

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Thanks for the suggestions so far. I'll be trying them when I get home! –  John Doucette Mar 13 '12 at 19:05
Just a quick question for clarification. A similar issue happened to me a few years back. Thing is, I was using a somewhat crappy "home mechanic" pedal wrench. That problem led me to purchase a "shop grade" pedal wrench; and I've not had the stuck pedal problem since. The upshot is that the "shop grade" wrench vastly improved the leverage. So, do you have a decent pedal wrench? –  user313 Mar 13 '12 at 21:18
I'm not sure. It was $15 at my LBS. Perhaps 12 inches long, 15mm.Is that a good one? –  John Doucette Mar 13 '12 at 22:15
15mm is most likely the right size as it's typical. However went with, the extra long 14” handle that provides the leverage to remove even the tightest pedals. parktool.com/product/professional-pedal-wrench-pw-4 –  user313 Mar 13 '12 at 23:01
One problem often encountered is that what "logic" says is the right direction to unscrew is the wrong direction. The pedal isn't threaded to resist the forces of simple friction that would want to unscrew it, but rather to resist "precession". Hold a pencil loosely in your left hand and then move the eraser around in a circle with your right hand (holding the eraser loosely also) -- the pencil will tend to rotate in the opposite direction from the motion of the circle. –  Daniel R Hicks Mar 14 '12 at 12:10

4 Answers 4

up vote 10 down vote accepted

Lengthening the wrench is your best bet. You don't need anything fancy, find a bit of pipe at your local hardware shop that fits over the wrench.

Watch your fingers. While trying to remove a tricky pedal, it gave suddenly and my knuckles hit the teeth of the chain ring. It was a daft and bloody mistake.

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You can also fit the crank in a vice so it does not move on you.\ –  Chris Belsole Mar 13 '12 at 18:53
How about. Put the left pedal back in. Align the pedals so they are level with the left one forward. Tape the wrench in position on the right pedal so it sticks out backwards. Now lean the bike against something and climb onto it. Stand up with your left foot on the pedal, and your right foot on the end of the wrench. Bob your body up and down so you apply your whole body weight to the problem. Watch out for the moment it does free because you'll probably fall off. :) Good luck. –  Scott Langham Mar 13 '12 at 19:20
The whole body weight seemed to be key. I had wedge a steel hammer across the cranks and then stand on the end of the wrench. Added a small dent to my chain stay in the process, so others should perhaps just head to the LBS... –  John Doucette Mar 14 '12 at 2:59
I put the chain on the big ring and wear gloved to avoid the knuckles in the chainring teeth. –  Matt Adams Jul 30 '12 at 18:31

Your best bet is to use mechanical advantage to your benefit. What you want to do is line the wrench up with the opposite crank, so that your hands are as close together as possible, now straddle the frame and force the two apart. Here's an image from Park's description of how to remove a pedal that illustrates it well:

pedal removal

The worst position for the wrench is 180 degrees opposite, so that the crank and the pedal are still parallel, but opposite. It will be almost impossible to remove a pedal in this orientation.

You are correct that the drive side pedal will have a normal thread, and needs to be turned counterclockwise for removal.

It generally takes a lot of force to remove pedals, because they tighten themselves as you ride due to precession. If you find this method still isn't working, refer to Scott's answer about lengthening your tool to gain leverage.

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I wasn't able to get the pedal off this way. Thanks for the suggestion though, this seemed like a good starting place. –  John Doucette Mar 14 '12 at 2:49

I made a very rough drawing which already helped me to release a singlespeed cog, using three wrenches: one for the locknut, one chainlink-bar to lock the cog itself, and another bulky one BETWEEN both, in wich I applied the actual force. I had to hold everything very firmly in place, and wrapping things with rubber might be helpful to avoid getting hurt and to help apply the right force in the right place, the right way.

In this rough drawing, the extra wrench (actually might be any metal bar) goes inserted in the chainring/crank-arm recesses, and is used to leverage the 15mm spanner.

Of course you would get everything in the best initial position as possible. Don't forget to use WD-40 some time before.

Good luck, hope it helps!

enter image description here

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Just be sure to be careful with this method. It's not hard to bend a chainring. –  user973810 Mar 13 '12 at 20:32
@user973810 yeah, the method is supposed to be used with care. In fact with proper position, just a minimal amount of motion is needed to release the stuck pedal, and the forces should be applied in a very controlled way. Actually (not shown in the drawing) the ideal would be to use the very crank-arm or the crank-spider (if any) as a contact point, and not the outermost parts of the chainring. –  heltonbiker Mar 13 '12 at 21:05
I ended up mixing this with Scott's method above. I had a sturdy steel cover on the outside of the chain ring which could bear the load easily enough. Would advise being very careful doing this though, since I put a small dent in my chain stay where it meets the bottom bracket in the process! –  John Doucette Mar 14 '12 at 2:53

First off, I've tried several tricks to remember which way to turn the wrench on which side, and he only rule that I can consistently remember is use the rule that rotating "forward" as if it was a wheel of the bicycle tightens the pedals and rotating "backward" loosens them.

If your pedals are standard size you should be using a 15mm pedal wrench. This wrench will normally have a longer handle for leverage. My trick is to orient the crank so that it is a close to parallel to the ground as the angle of the "nut" will allow, put the wrench on with the handle toward the back of the bike and press down. If you have a partner who can apply pressure to the other crank arm that might help.

In cases of a particularly stuck pedal I have used a rubber mallet to whack the handle of the wrench.

I've heard that if you have an aluminum crank, you can remove the crank arm and heat the pedal end over an open flame. The aluminum will expand an you should be able to remove the pedal easily, but I have never had to go that far.

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