A Short Lesson: Bike Pedal Threads (don’t underestimate them)

from Rookie’s Keyboard

Hello, friends

It’s time for the second post of this week. Lately, I’ve been on a row and would like to keep the rhythm going. As you know, in the past, I’ve had trouble maintaining my posting discipline but intend to change that in the future. 

What are we going to talk about today?

Bicycle pedal threads. I know. It’s not the most exciting topic out there, but yesterday, on my commute to the office, I saw a fellow cyclist (or a mechanic) in front of the LBS (local bike shop) inserting a ton of leverage in an attempt to remove a pedal. 

Why you may ask? I was already late and couldn’t stop to chat with him. Not that I would’ve done it anyway. I don’t want to annoy people who are already frustrated.

The three most logical sources of the described issue that I could think of are:

  • Corroded pedal axle threads
  • Mismatched pedal and crank threads (in other words, the pedals are not meant for the crank arms)
  • Cross-threaded pedals

The last two are a lot less common. If the bike pedal threads and those of the cranks aren’t meant for each other (a rare scenario on adult bikes), then the user would really have to force the pedals in. 

And since the pedal axles are made of steel whereas the crank arms are aluminum, the axle wins (steel is harder than aluminum) and “re-threads” the crank. As a result, it may become extremely difficult to remove the pedal. 

How do you avoid that issue? When the threads are healthy, you should be able to EASILY thread in the pedal with just your fingers almost 80% in. Only then use a pedal wrench (or some 15mm thin spanner) to finish the job.

I’d like to focus a bit more on the seized pedal axles scenario. 

The other day I talked about seized seat posts due to corrosion. In this case, the same could occur. 

As already mentioned, pedal axles are made of dense steel as they have to support a lot of weight and are capable of handling a lot of abuse. Meanwhile, the crank arms are usually aluminum.

Consequently, there’s a chance for galvanic corrosion to take place between the two. Galvanic corrosion represents a transfer of electrons between dissimilar materials (e.g., steel and aluminum). It’s catalyzed by a conductor like water.

In this case, the aluminum crank will be losing electrons. The final result is a seized pedal axle that requires a ton of effort to remove. 

How do you prevent that situation? 

Just grease the pedal axle’s threads. Grease isolates the affected surfaces from the environment and thus eliminates the exchange of electrons even when there’s moisture. Do not use other lubricants such as oil. It’s better than nothing but liquid lubrication disappears a lot faster due to its low viscosity. 

Grease is the perfect solution as it forms a protective layer that stays on for a long time. Another benefit of using grease is that the pedal installation process is smoother. 

Don’t obsess over the type of grease. Any kind is better than nothing. I use the cheapest that I can find in the local hardware store and have zero complaints. The two most commonly used types are lithium and marine-bearing grease. The second is considered better for particularly wet environments. That said, I don’t care.

That little trick (or should I say maintenance tip) will practically eliminate the chances of stuck pedals due to galvanic corrosion. 

But if you are already experiencing this problem, consider the following guide for untightening the problematic pedal(s).

Cheater Bar

You can effectively lengthen the handle of the pedal wrench by sliding a pipe (cheater bar) onto it.

The longer lever will amplify the force that you are generating many times. 


You could also spray WD-40, or something similar. Cover the area generously, wait for a couple of minutes, and then reattempt the disassembly.

You could combine methods 1 and 2 for better results.

Hot Water

Another less-known method is boiling water. If you pour boiling water on the affected area, the crank arm will expand faster and to a greater degree because aluminum is softer. The movement will make it easier to untighten the pedal.

+ Bonus Tips

If you don’t have grease on hand, you can also try: 

  • Anti-seize compound
  • Oil (doesn’t work as well as grease, but it’s a good temporary solution)
  • Vaseline (not ideal and doesn’t last long, but better than nothing)
  • Plumber’s tape(A thin layer of Teflon plumber’s tape works too. Wrap it around the pedal threads carefully. Don’t go crazy. If you put too much, you increase the chances of cross-threading MASSIVELY)

To make the procedure smoother, consider the following:

  • Wear latex gloves to keep your hands clean. I always store a pair in my tool bottle for dirty operations. You can also use the free nylon gloves from department stores next to the pieces of bread.
  • Keep a small rag close to remove extra grease.
  • Consider a dedicated grease gun. It’s not mandatory, but it makes the job easier. (I don’t have one…yet).

And by the way, don’t bother with Loctite Threadlocker. This substance has a different purpose – namely to prevent unwanted unthreading. And if a pedal is fully threaded in, it keeps itself tight.

How? The threading on bike pedals stops them from losing tightness during cycling.

The right pedal has a right-hand thread. The left one uses left-hand a.k.a. reverse threading.

This choice of engineering is strategic and takes advantage of a process known as mechanical precession and stops the pedals from untightening on their own. 

Also, thread lockers have poor coverage and won’t fully stop corrosion. 

Ok. Friends. I hope this post told you something new and will prevent you from experiencing the issue that the mechanic from the intro was facing yesterday. 

Until next time,

– Rookie






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