dnm_25

I am struggling to get a generic "alloy" seat post out of my 2006 Raleigh Rush hour steel frame. First I would like to ask if any one has an insight into what would be best to remove "alloy" from steel. Unfortunately Raleigh USA is not very specific about what kind of alloy the seat post is made of.
My real question though is, what kind of material should I go for when I buy a new seat post? I feel like steel on steel would be doom if it got rusted again, but I don't know which of the other materials I should get instead. I'm not very concerned with weight but more with durability. Anyone have any ideas?

tatfiend 

Virtually all Alloy seat posts are aluminum. In bicycles "Alloy" is commonly used for aluminum parts. Anything else will be called by the actual metal or material it is made of such as steel, Titanium or Carbon Fiber.

Aluminum seat posts should be well greased prior to installation to prevent what has happened to you. Sounds like poor dealer prep or that you changed seat posts after purchase for it to be frozen in a bike barely 2 years old, depending on the weather it has seen.

Here is an article from Sheldon Brown on removing stuck seatposts.

https://sheldonbrown.com/stuck-seatposts.html

z415

Use grease and you should be fine.

Panthers007

I'd just add that a teflon-based grease lasts a really long time. I've been taking components off a bike I greased with this back in 1983 - and the grease was still doing it's job. Thankfully!

fiataccompli

if it's stuck now & you've read the archives + Sheldon' Brown's stuff on stuck posts, I'd recommend leaving it out side in the cold (assuming it's cold where you are right now). I bought a mid-80s Fuji recently that had a stuck post that a bike shop had just given up on getting loose (after marring the heck out of it, no less). One morning recently when it was about 25 degrees outside, I took it outside & put it in the shade. A few hours later I walked outside and with about 2 twists the seat post came up. The aluminum shrinks I suppose more + faster than steel, so you get some force against the chemical bond that forms. The other, more harsh, approaches are well-documented all over the 'net.

JanMM

+1

wrk101

Did you buy the bike new? Is the post the right size (maybe its too big)?

Hard to believe a post on a two year old bike is stuck. I have picked up 30 year old bikes at thrift stores, that were highly abused, and the seat posts all came out.

tellyho

Yep. Doesn't matter what the post is made of. Grease makes the difference.

dnm_25

thank you all that replied! The bike is indeed 2 years old and I've drowned it in a full can of wd-40 and it still has not come out. I realized today though that there is a point in the seat tube where there is an inward bent, shaped like a ring. I then realized that that's where I had my Ulock holder when I first bought the bike. This would explain why the grease has had almost no effect. I had no idea the Ulock holder could have made so much pressure on the frame as to bend the seatube inwards and seize my seatpost. That Ulock thing was a piece of "it" too, I should have never put it on. I'll try letting my frame outside, although it is not that cold tonight.

nitropowered

Clamp the seatpost head in a vice and use the bike frame to twist out the post. Yes you will probably destroy the post but you are replacing it anyway right?

fiataccompli

ouch. how far down is that section that's indented?

LarDasse74

A few points:

I have never had good luck using WD40 to remove stuck parts. Rubbing alcohol, IMHO, works adequetly to dissolve the corrosion products that are bonding the post to the frame.

It is very unusual that a plastic U-Lock bracket could damage a stout steel frame like the ruch hour. Is it possible there is another cause? Maybe clamped too tight in a workstand? Do you have a picture of this damage?

If you are carrying a U-Lock, throw those terrible brackets away! Instead, get a rear rack that allows you to slide the lock down the side.

mcoomer

Yep, leave it in the cold and then give it a shot. Second, for your next seatpost I'd recommend a Thomson. Slap a very, very, very thin coat of bearing grease on the bottom half of the post and you're good to go.

Good luck.

Mike

dnm_25

"Is the post the right size (maybe its too big)?" by wrk101

Oh just to clear it up, the seatpost is the right size because it is stock and it came out once before (shortly after I bought the bike).
I will attach pictures and as you can see I have drilled a hole in the seatpost and used a rod to try and take it out, I have tried to have ice inside and use a blow drier on the outside, I have widened the slit at the top of the seat tube, I have used different chemicals, I have left the bike in the cold (about -11ºC or 12ºF, it didn't get any colder than that), and the seat post didn't move a millimeter. Trust me I have been using the same mark for about 3 months now to tell my progress, which has been none. And the clamp of the seatpost (where the saddle would be attached) actually came out in the process of pulling the seatpost out.
The seatpost is down to the point where my hand is in the picture. I'm sorry the quality of the pictures is bad, but that was on my cellphone.
Anyone has any other ideas?

dnm_25

oh and since the little head that clamps to the saddle came out I have had to use the seatpost clamp to pull it, also to no avail.

cman

Cut it off, then hacksaw out the rest. I did that once, hopefully not again

DannoXYZ 

Does the seatpost spin when you put a bar into that hole and try to rotate it? If so, the post isn't stuck, but the pinched part is keeping it in.

However, if it doesn't spin, you've got severe corrosion. PB-blaster is the best penetrating, corrosion-removing stuff out there. You can get it at most auto-parts stores. Works 10x better than WD40 and 3x better than Liquid-Wrench. Some people have also had good luck with dripping ammonia down the gap to dissolve the corrosion. A strong base, like NaOH would also dissolve the aluminium-oxide as well as the surface anodization and create additional clearance.

Force will also help. Try hanging the seat-post from the beams in your garage with chains from that hole you drilled. Then wrap some ropes around the bottom of the seat-tube above the BB to attach to a hanging platform of some sort. Then load up this platform with 50-lb barbell weights. I can't imagine it resisting 600-700lbs. Or if you have a block & tackle set-up, you can also use that to pull the frame away from the seat-post.