stuck seat post
 

Hey all. I just picked up a 15 year old 6 speed cruiser bike for $50. mechanically the bike is fine. My only problem is the seat post is stuck so I cannot adjust the saddle height.
Both the frame and seat post are made of steel. I have not tried penetrating oil yet to see if that will loosen it up but what other methods might work to fix this? I don't have a workshop or a lot of tools. Any advice would be appreciated. Thanks!

Also keep in mind you may not want to put that amount of time and labor into that bike. 6 speed stuff came out in the late 70s and early 80s so even in the mid 2000s it was quite outdated and the quality is going to be pretty low. 15 years after that with it having been abused to the point the seatpost is seized who knows what other issues there are going to be. It may be fine in some other places but a stuck seatpost isn't a good sign. You could end up putting a lot of time and money towards it without getting much in return for all that time and effort.

One trick is put a crappy old seat on the post, flip the bike onto its handlebar and seat, stand on the seat and twist the frame to try to loosen the post.

Other option is get a Sawzall, cut off the post about 1" above the frame, then very, very carefully Sawzall the inside of the seat post to cut it out, Careful to not saw thru the post and into the frame. I did this once.

Try some PB Blaster on it, let it soak in a day or two and try again.

A good alternative penetrant if you have the products at hand is a mix of acetone and ATF. I also like the sacrificial saddle--hit it on the nose with a mallet, too--not while you're sitting on it though. I have some good pipe wrenches so sometimes I use those. With the frame lying flat on the ground you can stand on the wrench handle. Then replace the seat post.

All good advice above and also whatever seatpost you end up using, the original or new, make sure to put some grease on the post when installing to prevent corrosion and this from happening again.

I suggest removing the bottom bracket and dripping some of whatever you are using (PB Blaster is commonly recommended) into the seat tube through the hole in the BB, and a few drops around the clamping area at the top of the frame; roll the frame around in your hands to encourage your chemicals to find all parts of the seat post/tube interface.

If the bottom bracket is also seized, consider the bike trash... these things often happen together (along with the stem quill being seized into the fork), and any one of these can be a deal-breaker - unless you luck out and everything is properly adjusted for you and running smoothly, the amount of effort or $$ regularly required to un-stick these things can easily be more than the bike is worth.

On a used bike you might check if any bottle bosses or other mounts on the seat tube weren't added by a previous owner and it's not just a rivnut or screw going into the seat tube and seat post.

Failing any joy with penetrating oil, I'd probably take the saddle off, turn the bike upsidedown and tighten down on the seat post with a bench vise and twist the frame to see if that will loosen it up.

Yes at that point I'm assuming the seat post is trash. So tighten the heck out of the vice

If you don't have a bench vise then a long handled pipe wrench will be my other choice.

Are you certain the seat post is steel? I'd think aluminum. But then again I am surprised a 15 year old bike only has six cogs on the rear. You probably paid 35 dollars too much.

Going back and seeing you did say cruiser bike I can imagine 6 on the rear. Personally I think from the turn of the century to just a few years ago manufacturers lost direction with cruiser style bikes. Seems like they have been getting better with them lately.

ATF? Alcohol Tobacco & Firearms? Not familiar with that abbreviation for a solvent. What is it?

ATF = Automatic Transmission Fluid. ;)

Thanks to all who have contributed advice! I basically got this bike as a winter "beater" for short trips of a mile or so for groceries. My only other bike is a Linus Roadster Classic single speed which is kept inside during winter. I ride that bike somewhere every day. I no longer bicycle commute daily so a single speed is fine for my needs during the summer. The bike in question is a Supercycle Newport Cruiser bike (Google it) and was sold by a chain store here called Canadian Tire. There was another one for sale here locally online for $150 but in a little better condition. Totally not worth it. No one will pay that. I may have overpaid at $50 but hey I just bought a footlong sub and a chocolate milk at Subway today and that cost me $13 :foo:

The frame on the Supercycle is (heavy) steel and I do know the difference between an aluminum seat post and a steel one. This one is chromed steel. The portion that is sticking out from the tube shows no rust or corrosion. The frame, wheels. brakes, derailleur are all in excellent condition. The one grip shifter works smoothly. I removed the heavy and ugly front and rear fenders and chain guard which are of no use to me. All I want to do is raise the seat up maybe an inch and I will be good. I am going to pick up some penetrating oil this week and apply that and let it sit for a few days and see if that may loosen it up a bit.

Steel into steel? Bench vise with an old saddle. Get it to rotate and it will come out. Don't grab onto the stays. Head tube and seat tube. Penetrating oil of your choice first. If it doesn't start turning quickly, stop, then soak it some more. I have bent frames with the brute force method, so don't overdo it and don't grab the stays.

Brute force method not recommended for aluminum into steel as you have other issues.

I'm assuming you have a straight round seat post, no integrated clamp. You could clamp onto the seat post into the vise, but you will tend to distort the seat post.

You can still find six speed bikes brand new at the box store of your choice. Those bikes have kept the continued production of 6 and 7 speed freewheels for those of us with older bikes. So myself, I am thankful they are still out there.


No workshop? Find a co op in your area if possible. Or a neighbor with a bench vise. Or a friend at work?

Aluminum can corrode into steel, forming a somewhat permanent bond. Those can be a lot more work to free up. You are fortunate with steel into steel.

Yes, my local Walmart still sells a 7 speed cruiser. My neighbor also happens to repair and resell bicycles on the side and has a shop in his garage. He is on standby if I need more assistance.

Also, you should put the fenders back on - the added weight will be saved the first time you don't have the same weight of water soaked into your pants. Also, especially for a winter bike, nice full fenders prevent a lot of salty spray from hitting drivetrain and other bike parts that can rust. If they are too heavy, you can get plastic replacements, although the metal ones will be tougher and last longer int he winter when plastic might become brittle in the cold.

Of course, this is all assuming you can get the seatpost out - like I said before, if the seatpost, stem, or bottom bracket are seized the bike is basically trash.

The original heavy steel ones were very pitted with rust in the inside. I am considering replacing them with mew plastic ones but I don't really care so much about fenders since like I said the bike will be used for quick winter errands. Plus it's my bike and I will do what I please.

Also...I don't know why you people keep saying the bike is trash? It's not a bad machine and I find it rather rude and insulting to denigrate someone else's bicycle just because it doesn't conform to your opinion of what a "good" bike should be? It seems fine to me. I was only asking for help and certainly don't need your opinion on how horrible my bike is.

Thanks anyway.

While I think people are being a bit excessive here, we’ve also seen too many people end up buying enough new parts that their cost even before labor exceeds the cost of purchasing the same box store bike brand new. They don’t want you to be in that position, though fortunately it sounds like that’s not the case.

I would consider any corrosion inside the fenders as corrosion they prevented from ending up on the frame, but at what it’s cost you, I’m guessing you’ll get decent value out of it long before it’s rusted through.

As for the sawzall comment above, if you do go that route (or with a hacksaw blade), hold the blade in a pair of vise grips and slit out the center by hand, then you peel the seat post inwards. While I’d try the other methods first, it doesn’t take as long as you think. Just do run a power tool in there. It’s too easy to overshoot and trash the frame that way.

There is no reason to take it personally https://www.bikeforums.net/images/smilies/lol.gif
A stuck seatpost is often an irrecoverable problem, and if you can't get the seat adjusted to a reasonable height for yourself the bike is literally worthless to you. I don't care if it's a cheap bike or expensive bike or a cruiser or a lightweight racing machine, stuck seatpost = garbage.

I can sympathize. I often spend way too much time and sometimes money fixing something that many wouldn't fix. It's my own little way to counter the throw-away society. And I volunteer at a non-profit bike shop that has keeping old bikes out of the waste stream as a goal.

And I ride older, cheaper bikes that nobody comments on when they're looking at each others bikes at a rest stop. Welcome to the world of the retrogrouch.

Short winter errands are the exact situation where fenders make the most sense.. You don't have to worry about changing clothes or getting wet, plus speed is unimportant so a bit of extra weight is 0% an issue. Pitting and rust don't matter. Anyhoo, riding a bike in the winter is pretty much a death sentence for the bike. Don't believe me? Ride it for the winter then get back to me in the Spring to tell me how the bike is doing.

You got issues, my dude.

I used to volunteer at such a place, and bikes were evaluated and put into one of two streams - if the bottom bracket, seatpost and stem were all removable then the bike was slated for rehab and sent back out; if the seatpost, bottom bracket or stem was seized then the bike was stripped of all usable parts and the frame/fork/seapost was sent to the metal recycler.


If OP has his gotch in a wad over some comments about his old Supercycle cruiser with a seized seatpost, his skin is obviously too thin to be a successful retrogrouch.

I don't recall any saying your bike is trash. You seem to be imagining that. What most are saying is that you'll quickly have more into this bike than what it's worth.

Many of us don't sugar coat what we say. So don't read it as any judgement on you or your bike. What you find useful, use. Ignore the rest.

Or should we not have a frank discussion?

thanks for all the help...enjoy the snobbery

i dont need it

You seem to be very judgemental. RDWHAHB!

Wtaf?