Condensed answer: Greasing pedal threads is beneficial. Grease makes pedal installation smoother and prevents corrosion of the involved materials.
The Benefits of Greasing Pedal Threads
Grease stops water, dust, and dirt from getting between the pedal threads and the crank arms’ mating threads. This greatly lowers the chances of rust formation.
2. Prevention of Galvanic Corrosion
If the pedal threads and the crank arms are made of different metals e.g., steel (threads) and aluminum (cranks arms), galvanic corrosion could take place.
Galvanic corrosion is a deterioration process occurring when two dissimilar metals are in contact and in the presence of a conductor like water.
When those conditions are met, a transfer of electrons begins from one of the metals to the other.
In this case, aluminum is the metal giving up electrons even though by itself it’s more corrosion resistant than steel.
However, this is a custom scenario known as preferential corrosion.
Once corroded, the crank arm bonds to the pedal threads. As a result, it becomes very difficult to remove the pedal.
Greasing the threads of the pedals greatly reduces the chances of galvanic corrosion.
Note: Another option would be anti-seize compound/paste.
3. Smoother Installation
Grease lubricates the points of contact and makes it easier to tighten the pedals to the necessary torque settings.
If you want to see the difference between grease and no grease, you can do the following test.
1. Apply grease only to one of the pedals.
2. Tighten both pedals to the required specifications. (You would need a torque wrench for accurate measurement.)
More than likely, the greased pedal will tighten smoothly and without excessive noise, whereas the “dry” one would complain a bit and may even squeak.
What Type Of Grease Should I Use?
For this particular purpose, almost any grease will do – from the cheap tubes sold at hardware stores to the expensive bike-specific versions. The two most commonly used types are lithium and marine bearing grease.
FAQ: My pedals are already stuck. What should I do?
If you are dealing with a pedal fused with a crank arm, you can try the following methods to get it unstuck:
1. Extra Leverage
You can extend the handle of the pedal wrench by sliding a pipe (cheater bar) onto it.
The longer lever will increase your mechanical advantage and consequently the torque applied to the pedal.
You could also spray WD-40, or a product with similar properties, over the area and then reattempt the disassembly.
You could combine method 1 and 2 for better results.
3. Hot Water
The spindle/axle of most pedals is made of steel, usually Chromoly because the area is subjected to a lot of tension and stress.
Meanwhile, most cranks are aluminum for weight-saving purposes.
If you pour boiling water on the juncture where the cranks and pedals connect, the crank arms will expand faster and to a greater degree because aluminum is softer. The extra opening will make it easier to “free” the pedal.
Grease vs. Anti-Seize For Pedal Threads
Grease is a lubricant and can therefore be used on moving parts. Anti-seize compounds are not lubricants. Тheir main purpose is to prevent two parts from sticking to each other.
Dedicated anti-seize compounds can’t be applied to moving parts because they increase friction.
In consequence, grease is a more versatile product because it covers both functions – lubrication and anti-seizure.
When it comes to pedal threads, both substances get the job done because the parts aren’t moving. (The pedal is rotating around the spindle, but the spindle itself remains immobile.)
FAQ: I don’t have grease at the moment. Can I use something else?
If you don’t have grease at your disposable, you can try some of the following methods:
1. Anti-seize compound
A dedicated anti-seize compound will get the job done.
Oil doesn’t work as well as grease, but it’s a good temporary solution.
If you don’t have anything else, Vaseline will do the trick until you get the proper stuff.
4. Plumber’s tape
You could also use a thin layer of Teflon plumber’s tape. Wrap it around the pedal threads carefully. Don’t go overboard. If you put too much, you increase the chances of cross-threading.
FAQ: Can I put Loctite Threadlocker on pedal threads?
Technically, you could, but it’s not the most optimal choice because thread-lockers do not have the coverage and protective properties of grease.
Also, the threading on bike pedals prevents them from losing tightness during pedaling.
The right pedal has a right-hand thread. In different, the left one uses left-hand/reverse threading.
This choice of engineering isn’t random. It takes advantage of a process known as mechanical precession. As a result, pedaling tightens the spindles.
If the pedals are tightened well initially, it’s close to impossible for them to unscrew. This eliminates the need for a treadlocker.
FAQ: My pedal fell off. Is it because of too much grease on the threads?
No. Too much grease on the threads cannot result in a pedal falling off. The most likely culprits are:
1. Low Torque Settings
If the pedals aren’t sufficiently tightened, they may unscrew due to vibrations.
2. Damaged/Stripped Threads
The threads of aluminum crank arms can be cross-threaded and easily damaged. The result is an inability to tighten the pedals sufficiently. The only way to fix this problem would be to replace the damaged components.
3. Seized Bearings
If the bearings of the pedals block completely, it’s possible for the pedal to unscrew at some point. This is a very rare scenario, however.
The solution would be to take off the pedal and service it. (Cleaning and lubricating the bearings.)
FAQ: Applying grease seems tricky. Any tips to make it easier?
Yes. A few.
1. Use thick latex gloves to keep your hands clean. (Tip: Store a pair in your saddlebag for dirty repairs on the side of the road.)
2. Keep a cotton rag close to remove extra grease.
3. Purchase a grease gun. Many professional mechanics have this tool in their arsenal because it adds dexterity, precision, and “dose control” when applying grease.
FAQ: Why are so many cyclists using marine grease?
Marine grease is popular among cyclists because it’s highly water-resistant, affordable and long-lasting.
FAQ: Can I use WD-40 instead of grease?
Grease is the way. It’s thicker, thus more dust and water repellent, and has better lubrication properties than WD-40.
In this case, WD-40 is only good for cleaning the surfaces before applying grease.
- It’s necessary to grease pedal threads to prevent corrosion and facilitate installation.
- If the pedal threads aren’t greased, the pedals will fuse with the crank arms, making removal a difficult task.
- You can use anti-seize compounds too because the involved parts aren’t in dynamic motion.
- Pretty much any grease will do the job. (Dedicated white bike grease, lithium grease, marine grease…etc.)
- If you don’t have grease, you can temporarily use oil or Vaseline.