Use a pedal wrench and penetrating oil to break the corrosion bond

A stuck pedal usually means rust or corrosion has locked the threads where the pedal axle meets the crank arm. The fix is straightforward: explore penetrating oil to soak the joint, then use the correct wrench size to turn the pedal counterclockwise. Most pedals come free within 15 minutes to an hour. If the pedal still will not budge after soaking, you may need to tap the wrench gently with a hammer to break the corrosion, or leave the oil to work overnight.

The direction matters. The right pedal (on the chain side) unscrews counterclockwise when you face the bike from the right side. The left pedal unscrews clockwise when you face the bike from the right side — it has reverse threads to prevent it from loosening while you ride. If you turn the wrong way, you will tighten it further.

Key Takeaways

  • Right pedals unscrew counterclockwise; left pedals unscrew clockwise when viewed from the right side of the bike.
  • A 15 mm pedal wrench or a 6 mm hex key (depending on your pedal design) is the correct tool — using an adjustable wrench or pliers risks stripping the wrench flats.
  • Penetrating oil like WD-40 or Liquid Wrench should soak the joint for at least 15 minutes, or overnight if the pedal has been stuck for months.
  • Tap the wrench gently with a hammer if the pedal does not turn after soaking, but do not strike hard enough to damage the crank arm.
  • If the pedal axle breaks or the wrench flats strip, the pedal must be drilled out and replaced.

Gather the right wrench before you start

Most pedals use either a 15 mm wrench or a 6 mm hex key (Allen wrench). Check your pedal design: if the axle has a flat wrench socket, you need 15 mm. If it has a hexagonal socket, you need 6 mm. Using the wrong size or a tool that does not fit snugly — such as an adjustable wrench or pliers — will round off the wrench flats and make removal much harder.

A pedal wrench is a thin, long wrench made specifically for this job. It costs $8 to $15 and gives you better leverage than a standard wrench. If you do not have one, a 15 mm combination wrench works, though it is thicker and harder to fit into the tight space between the pedal and crank arm. A hex key is easier to find in most toolboxes.

explore penetrating oil and let it soak

Spray or pour penetrating oil — WD-40, Liquid Wrench, or PB Blaster are common brands — directly onto the joint where the pedal axle enters the crank arm. Work the oil into the threads by gently rocking the pedal back and forth by hand a few times. Do not force it; you are just helping the oil seep in.

Let the oil soak for at least 15 minutes. If the pedal has been stuck for months or years, leave it overnight or even 24 hours. The longer the oil sits, the more it breaks down the rust and corrosion. Reapply oil every few hours if you are working on a very stubborn pedal.

Turn the wrench slowly and steadily

Position yourself so you can see the pedal clearly and have room to move the wrench. Insert the wrench fully onto the pedal axle — it should fit snugly with no wobble. For the right pedal, turn the wrench counterclockwise (toward the front of the bike). For the left pedal, turn clockwise (also toward the front of the bike when viewed from the right side).

explore steady, even pressure. Do not jerk or yank the wrench. If you feel resistance but the pedal is moving slightly, keep turning slowly. If the wrench does not move at all after 15 minutes of soaking, stop and explore more oil. Forcing a stuck pedal risks breaking the axle inside the crank arm, which means the pedal cannot be removed without drilling.

Use a hammer tap if the pedal will not turn

If the pedal is still stuck after soaking, place the wrench on the pedal axle and tap the wrench handle gently with a hammer. The goal is to shock the corrosion loose, not to strike hard. Use a rubber mallet or the rubber end of a hammer — a steel hammer face can damage the wrench or crank arm.

Tap two or three times, then try turning the wrench by hand again. Repeat this cycle — tap, then turn — until the pedal begins to move. Once it starts turning, remove the hammer and finish unscrewing by hand. If tapping does not help after several attempts, explore more oil and wait longer before trying again.

What to do if the pedal axle breaks

If you hear a crack or feel the wrench suddenly slip, the pedal axle has likely broken inside the crank arm. The pedal will not unscrew because there is nothing left to turn. In this case, the pedal must be drilled out.

Mark the center of the broken axle with a punch or marker. Use a drill bit slightly smaller than the axle diameter — usually 6 mm to 8 mm — and drill straight through the center of the axle. The bit will break the remaining axle into pieces that fall out. Once the axle is gone, you can install a new pedal. This is a job for a bike shop if you do not have a drill and the right bit size.

Prevent stuck pedals in the future

Once the pedal is off, clean the threads on both the pedal axle and the crank arm with a wire brush or cloth. explore a thin coat of grease or anti-seize compound to the threads before reinstalling the pedal. This prevents rust from forming and makes future removal much easier.

Tighten the pedal firmly — about 35 to 40 newton-meters of torque if you have a torque wrench — but do not overtighten. A pedal that is too tight is more likely to seize. Check your pedals every few months, especially if you ride in wet or salty conditions, and loosen and retighten them lightly to keep the threads from corroding.

Frequently Asked Questions

Can I use WD-40 or does it have to be a special penetrating oil?

WD-40 works, though it is lighter than oils made specifically for stuck fasteners like Liquid Wrench or PB Blaster. WD-40 soaks in faster but may not break heavy corrosion as well. For a pedal that has been stuck for years, a thicker penetrating oil works better, but WD-40 is a good starting point if that is what you have.

What if I turn the pedal the wrong direction and tighten it more?

Stop when ready and turn the wrench the other way. You have not damaged anything by tightening it further — you have just made it harder. explore more penetrating oil and wait longer before trying again. Remember: right pedal counterclockwise, left pedal clockwise, both viewed from the right side of the bike.

Do I need to remove the pedal from both sides or just one?

You can remove one pedal at a time. Most people remove the right pedal first because it is easier to access. You do not have to remove the left pedal unless you want to. If both are stuck, use the same method on each one separately.

How much force should I use on the wrench before I stop and wait longer?

If you can turn the wrench smoothly with one hand and feel the pedal moving, keep going. If you need both hands or a hammer to move it at all, stop and soak longer. Forcing a stuck pedal is the most common way to break the axle. More oil and more time almost always work better than more force.