Jim’s Tech Talk
By Jim Langley
Longtime RoadBikeRider readers will remember cycling writer Scott Martin who wrote the Scott’s Spin humor column for RBR. I actually met Scott way back in 1989 when I joined the staff of Bicycling Magazine where he already worked. After that great gig we both ended up working together at a cycling dot com.
Since then we’ve both moved on but have kept in touch because we’re teammates on the Spokesman masters cycling team – for about 15 years now. Suffice to say we’ve had some fun adventures together writing about and riding bikes.
Scott puts on two weekly group training rides in town and I tag along when I can. At the last one he mentioned to me that he needed help with one of his bikes, a classic 1990s Burley Samba tandem (photo). FYI: Burley is still in business but it doesn’t appear that they make tandems anymore https://burley.com/ .
Scott told me that he was getting ready to sell the bike, tried to adjust the rear seat height and found that the seatpost was frozen in the frame. No matter what he tried, he couldn’t get it to budge, it was stuck in place. I said I’d be happy to fix it for him. Here’s how I got it unstuck in case you ever run into this issue.
Why seatposts can get stuck, become frozen in the frame
The most common reason for a seatpost to freeze in a frame is lack of lubrication. Maybe the seatpost wasn’t greased enough when it was installed. Or the grease could have dried up over time – the more time the more likely it will dry. Most seatposts (including the ones on Scott’s tandem) are made of aluminum.
When an aluminum seatpost is put in a steel frame (the Burley is a steel frame) with no lube or not enough lube in-between, it’s common for corrosion between the dissimilar materials to occur. And this is the thing that causes most frozen seatposts. The two metals bond to each other which can make it very difficult to break the seatpost free.
Materials to Free a Frozen Seatpost
- Penetrating lube such as Liquid Wrench
- Heat gun
- Ice packs or a freeze spray in a can
- Quality vise securely attached to a workbench or a pedestal vise bolted to the floor
- If the vise is attached to a workbench, the bench should be sturdy and attached to the wall so it cannot move
- Emery paper or sandpaper to remove any corrosion on the seatpost once it’s removed
- Grease or anti-seize to prevent the seatpost freezing again
The Right Tools Make The Job Relatively Easy
I took a video as I worked on Scott’s tandem so that you can see what I did.
The key thing is that I have a heavy-duty vise attached to a workbench. The workbench is bolted to the wall. This provides the perfect way to remove a stuck seatpost.
What was weird about this seatpost was that it wasn’t even inserted past the minimum insertion line of the post. This meant that only about 2.5 inches of tube was inside the frame. That’s so little that I thought the post would come out without much of a struggle. I was wrong. It refused to move.
Get Some Lube in There
To try to start freeing the post, I removed the saddle and the frame seat clamp and applied a penetrating lube to the top of the seat tube. Dripping the lube on the seatpost caused it to run down and in between the post and frame. I did this a few times daily over a couple of days. I also tapped on the top of the seatpost with a hard mallet to vibrate it to encourage the penetrant to travel into the frame. Do not strike the seatpost with anything hard enough to damage the seatpost!
If you keep at it with penetrating lubes like this you can usually get even the most frozen parts to break free. But, Scott already has a buyer for his tandem so I had to get it done quickly.
The Setup for Max Leverage
To do that I inverted the bike and put the top of the frozen seatpost in the bench vise. The Kalloy seatpost has a micro-adjust head, which means it’s flat on the sides and perfect for clamping securely in the vise. With the tandem in this position, you have the entire front half of the bike to use for leverage.
However, you want to be careful. You could break a seatpost if you were unlucky and yanked the wrong way or if the tandem became unbalanced, started to come out of the vise or fell over.
Expansion and Contraction
Before trying to move the frame to break the seatpost free, I did two more things that help free frozen parts. First, to expand the seat tube of the frame, I warmed the steel frame in that area with a heat gun. The frame is painted so I was careful not to heat too much or I could have burned the paint.
After that I put some ice packs around the seatpost and left them there to get the aluminum cold so that it would contract. All I had were the ice packs. There are freeze sprays available that would have gotten the post colder and faster too, such as Finish Line’s Chill Zone https://amzn.to/3WU2sdK
Easy Does It! Don’t Break the Seatpost!
With all this preparation complete, it was time to try to break the seatpost free. You want to do this carefully. The bike provides plenty of leverage to damage, even break the seatpost if it still refuses to budge. So instead of just yanking the frame to the side to put massive force on the seatpost, you just move the frame as far as the seatpost lets you move it. You go in one direction and then the other direction.
This puts a significant twisting force on the seatpost in both directions. I did this twice in both directions and was ready to heat the frame and cool the seatpost again before trying again. But, on the last push, the seatpost made the telltale loud “click” that frozen parts make when they break free. Once I heard that I sprayed some more penetrant onto the post through the gap in the seat tube and let it sit a bit to find its way inside.
Get More Lube in There
You don’t want to get too eager and start tugging on the seatpost right away. It’s free but it’s still stuck a little. If you push and pull on the frame too much you’ll heat the seatpost, which expands it and makes it want to bind again. You might break the post. So take it easy. Keep applying the lube and gently moving the frame until the seatpost is fully free and turning the way it should.
At that point, remove the bike from the vise and celebrate as you extract the seatpost from the frame. Clean everything up and lubricate the seatpost, clamp and frame before reinserting the post. If the post showed any signs of corrosion, clean it with fine sandpaper.
How To Prevent A Frozen Seatpost
All that’s needed to never have to deal with a seatpost freezing in the frame is remembering to check the seatpost regularly, at least every 6 months for bikes ridden regularly and especially if they’re ridden in the rain. To check the seatpost, loosen the clamp bolt and try to raise or lower the seat. It should move with a little resistance from the tight fit. If it’s very tight or resists moving, extract the seatpost, inspect it for any corrosion. If there is any, clean it off with sandpaper. Then relube the seat tube of the frame with grease and reinstall the seatpost. That simple procedure should prevent a seatpost from ever freezing in a bike on you.
Carbon Bikes and Seatposts
You could use this same vise technique with an aluminum seatpost in a carbon frame but only if it’s a round seatpost. Also you wouldn’t heat a carbon frame. You would just chill the aluminum seatpost.
For aluminum and carbon seatposts you would lube them to prevent them freezing again. The best thing for this is an assembly paste like Park Tool’s Assembly Compound https://amzn.to/3Xmh0Vf
Your Turn
If you’ve dealt with frozen seatposts before, please share what happened and how you fixed it. There are lots of different ways it can happen and various ways to fix it too, so your tips could help another roadie out. Thanks!
Jim Langley is RBR’s Technical Editor. A pro mechanic & cycling writer for more than 40 years, he’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Tune in to Jim’s popular YouTube channel for wheel building & bike repair how-to’s. Jim’s also known for his cycling streak that ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
I have had to use a car jack to extract a frozen post, flipped the seat around and put the jack on thin piece of
wood on the top tube and the jack between the top tube and seat. This is all after a giant dose of BIG SHOT blaster in the seat tube soaking for 24+ hours
Before my periodic seatpost loosening I use a marker to indicate my insertion spot on the post, to make it easier to reinsert to the right point.
I put “Never Seize” on my seatpost (the old lead based kind) had to clean it off with leaves alongside the road as the post would not stay in position.
My Easton carbon seat post was firmly stuck in my titanium Douglas frame.
After trying a multitude of techniques involving my bench vise, heating, cooling, and penetrating oil it remained firmly stuck.
Ultimately, I placed the bike upside down with the seat clamp in the vise, attached one end of a come-along around the bottom bracket and ran the other end up to an eyebolt I installed in my garage’s ceiling. After tightening down the come-along a fair amount and twisting the bike back and forth in the vise the seat post eventually broke free – “broke” being the key word here as about 1″” of the end of the seat post remained in the seat tube where it still resides. Fortunately, the new aluminum seat post I installed was short enough to not interfere.
I had used special carbon grease when assembling the bike but had not checked it every 6 months as the article advises. Lesson learned.
A good friend of mine was riding across the US with a supported group a few years ago. For comfort reasons he was riding his very heavy touring bike which he normally used with panniers, but he didn’t need them for this trip. After riding for over a week he realized he wasn’t able to keep up with the group as they were riding lighter and faster road bikes. Plus, he was working a lot harder than he expected, was exhausted and still had 2/3 of the trip to go. He called and asked if I’d ship him his road bike as soon as possible.
No problem! I have a great hardcase for shipping and would go get his bike, break it down and ship it out that same day. I rushed to his house (about 30 minutes away) brought his bike home and started breaking it down. The seat post wouldn’t come out!!! The bike was a Titanium frame with an Al seat post. I tried everything but no such luck. I called our local LBS and they gave me lots of great tips, but nothing helped. I could twist it around a little, but it would not budge. Plus, I was running out of time. I needed to get it shipped out that day so it would arrive at the destination he gave me when he got there. The penetrating oil needed to sit for a day or two, but I just didn’t have that much time.
His bike just wouldn’t fit in my case with the seat post in the frame. But I just happened to have an older cardboard bike box from a bike I’d bought a couple years before then. I had to take a lot more stuff off his bike, but it barely fit in the bike box. I bought some pool noodles and covered everything as best I could. Fortunately, the bike arrived on time where he needed it, all the parts were intact, and he was able to get everything reassembled without an issue. He went on a completed the ride with a lot more comfort. I need to ask him if he ever tried to remove the seat post and if not, give him your tips!!!
This happened to my tandem too. I don’t remember how I solved it, but hanging the heavy tandem by the saddle did nothing! But what I came to say is that I discovered that you can dissolve thread locker with Isopropyl alcohol. I was using it in a different context, but I thought bike mechanics would like to know. Brute force and heat is not a good idea if it can be avoided. But of course, don’t ever use threadlocker on a seatpost!
I received a carbon frame that had part of a frozen carbon seat post in it. This was lopped off near the top of the seat tube of the frame and an attempt with a hacksaw was started. I thought about this for some time and did cut a little more with a hacksaw. I took it to a machinist and asked if they could bore it, but they did not want to touch it. I found these adjustable hand reamers that I could fit inside the seat post tube and make small amounts of progress working out to the frame. Keep in mind they were cheap and probably dull from being made of cheap steel. I also at times used a power drill to make some progress while it was still thick.
https://www.amazon.com/dp/B081CCNX5C
A good reminder to pull some of my seat posts and lube them up!
Chemist here: petroleum based penetrants will not dissolve aluminum oxide! Invert the frame and use a small plastic polyethylene dropper bottle to drip some 10 percent ammonia (ammonium hydroxide) through a bottle cage mount into the seat tube. The ammonia is available at a janitor supply store – conventional ammonia is a few percent, too dilute. Add a few drops a day. I once took a month to loosen an Al post in a steel frame. Scrub the post with bronze wool. Steel wool will leave iron particles, leading to another stuck post. Clean the seat tube with a car brake cylinder hone. Lightly! Carefully! Grease post and frame and tell your friends what you did.
Thanks for the great frozen seatpost stories and removal tips everyone!!
Jim