Freeing a Stuck Bicycle Seatpost in a Vintage, Steel Bicycle

One of the most frustrating things is when an old seat post becomes stuck. The New World project had just such a seat post. The usual pulling and methods did not work, so I resorted to my old standby: heat and Kano Kroil.

First, I removed the external great seat post clamp and bolt, exposing the top of the seat tube. The seat tube has a cut in it which supposedly allows for the seat to be easily extracted once the over-clamp is loosened. That did not hold true this evening.

So I set to work with a Bernzomatic small butane torch and Kano Kroil. I realize that some people absolutely will not use the heat on their seat tube. It depends on the bike though. A particularly rare or valuable bicycle probably should not be subjected to heat. However, this bike is of only moderate value, and the portion of the seat tube I'm heating will be invisible anyway because it is concealed by the great over-clamp once reassembled.


1. Heat the mouth of the tube with the torch. It does not need to be red hot, but should still be quite hot (too hot to touch).
2. Apply Kano Kroil at the spot where the tube and the seat post touch
3. Wait for it to cool

Now you can begin to try to coax the post out. I like to use an old saddle and clamp it on the post nice and tight, then use the saddle as a handle to pull up the post. I first try to pull straight up, but if that doesn't work, I resort to turning the seat post while pulling. Again, this may scratch the post to some degree, so use caution if you have a rare or valuable bicycle. Since I ride my bikes, I need to free this seat post to properly set up the riding position. I prefer doing full turns to twisting back and forth.

Repeat the heat and Kroil as needed.




Sure enough, after quite awhile of pulling and oiling, the seat post came out without any cracks or bends. There are a few scratches, but nothing bad. Letting the Kroil do the work for you really makes a difference. The Kroil did not harm the Schwinn paint, but I also would not want to make a mess with it either.

REMEMBER: wipe off any excess oil that drips onto the finish, even if you think it's paint safe.


Appendix:


Machinist's Workshop Magazine discussed solvents used for freeing frozen parts. They found in freeing a frozen part:

       Product / Average load / Price for each fluid ounce


  • None / Required 516 pounds of force to free / (no cost)
  • WD-40 / 238 pounds / $0.25
  • PB Blaster / 214 pounds / $0.35
  • Liquid Wrench / 127 pounds / $0.21
  • Kano Kroil / 106 pounds / $0.75
  • Auto Transmission Fluid (ATF)-Acetone mix / 53 pounds / $0.10

NOTE: do NOT attempt to use the ATF-Acetone mix on anything with paint or near paint. The Acetone will compromise the paint it touches. Go with Kroil or Liquid Wrench instead.


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