Hot answers tagged seatpost
14
You might find a suspension seatpost to be comfortable, but a suspension seatpost is not a substitute for a full suspension bike. The purpose of a suspension seatpost is purely comfort (though as mikes mentions, not everyone agrees that they achieve this goal), where as the purpose of a full suspension bike is first and foremost control. Suspension on the ...
13
Before you take any more forceful measures, it may be a good idea to think a little about chemistry:
'Rust' is typically the name put on any type of corrosion, but technically & specifically, it is the corrosion of iron (or steel) to form iron-oxides.
Although your bicycle is most definitely steel, your seatpost is not -- it's aluminum-alloy, which ...
9
This is a tough one. It's not impossible but you really need mechanical advantage. If you can clamp the seatpost, you will get the best chance at freeing this. You will probably damage/lose the seatpost with this method.
Make sure the seatpost is free of
grease and oil on the outside.
Turn the frame upside down and clamp
the seatpost into a bench ...
9
As the person who made that claim, the reason is that allegedly some greases can attack the epoxies found in some carbon fiber applications, causing a breakdown of the CF structure, and causing expansion which will jam the post in place.
The epoxy will otherwise not corrode, so it's not necessary for that purpose. The manufacturers also recommend you do not ...
9
Phil Wood, the owner of the bicycle tool and components company of the same name, once commented that his number one requirement when he was buying barrels of grease for his company, was that it be the exact same green color shade as the previous batch, so that he didn't get too many phone calls asking what he'd changed.
Point is that the "bike specific" ...
9
On old steel bikes a good reason would be to prevent the seatpost from rusting onto the frame, thus preventing saddle height adjustment.
More recently I understand from my LBS that you do it to prevent water from seeping into the frame along the (imperfectly sealed) seatpost. Depending on your frame you could end up carrying one or more kilo's of water with ...
8
Carbon parts will cause aluminum to oxidize, as a chemical reaction which is why seat posts wind up stuck in frames. But that isn't why this is necessary.
"Carbon grease" is not actually grease. It's a friction compound which increases the friction between your fancy carbon seat post and your frame. Increasing the friction allows a lower torque on the ...
8
Greasing your seatpost will prevent problems like this: "Removing Seat Post rusted into downtube".
Don't use chain oil, grease is what you want. As whatsisname pointed out, all fasteners on your bike should be lightly greased. This is what keeps them from corroding and seizing over time, becoming a real pain to remove.
If you have trouble with a ...
7
You should absolutely grease your seatpost (unless it is carbon fiber). It won't slip around if your seatpost clamp is properly tightened.
Get a thing of grease from the bike shop, like the park tool grease. Better yet, get the big tub.
Then, generously apply it all over inside your seattube. When you think you have enough, add some more. Then put the ...
7
I present you with evidence that seatposts can, in fact, seize!
Alloy and steel seatposts are both perfectly capable of seizing to both alloy and steel frames.
IIRC, carbon seatpost/frame combinations may need carbon assembly paste for almost the opposite reason: to increase friction and reduce the torque required for a good grip.
6
In general, you've hit the high points yourself.
The benefits (and issues) will vary by post model, manufacturer, and design. Carbon fiber is a very versatile material engineering wise.
Storck makes 2 carbon posts, which are externally identical. But one is a comfort post, which focuses solely on smoothing out your ride, and the other focuses on being ...
6
The best grease is the grease with the least amount of contaminants. Everything else is secondary to that.
Naturally grease does not come with contaminants in it, but, in the workshop it attracts any dirt going, as if it were some huge magnet.
Therefore, packaging is important. The large tub that you have for the car/motorbike/boat/unicorn cage might not ...
6
Seat post suspension is not designed for efficiency.
It is designed to add comfort to a hard tail mountain bike frame. There are only a few really good suspension seat posts, and they are rarely used on hybrid bikes. Almost always, you will find that the suspension post on a basic hybrid is just a spring in a tube.
Occasionally, they add the ability to ...
5
While it's true that your hips rocking indicates that the seat is too high, there is a different rule of thumb for knee pain related to the fore and aft position of the saddle. It's easy to remember:
If your knee hurts in front, your seat is too far forward.
If your knee hurts in the back, your seat is to far backward.
The most important thing to ...
5
Untested and at-your-own-risk, but this is what I would try:
Soak the rusted join with WD-40 from above and below (ie. flip the frame and spray down the seat tube). Let it sit for a few hours or overnight.
Secure the frame against something solid, like a heavy workbench (not a repair stand!).
Put an old saddle you don't care much about on the seat post.
...
5
Heavy, water-proof grease is a good idea.
Slipperiness isn't the reason for the grease. The goal here is to keep out moisture and oxygen, thereby discouraging oxidation. Aluminum oxide is especially problematic, as its molecules are substantially larger than the aluminum molecules in your seat post. Oxidation will cause it to jam very tightly.
In general, ...
5
You can probably use a small wire brush to get the rust out of the frame and for the future use JP Weigle Frame Saver spray. It acts as a rust inhibitor so should slow down/stop any rust forming on the inside of the frame. You can get frame saver at JensenUSA (I'm sure there are lots of other spots too).
...
5
Unfortunately, this is a common issue with more basic seat posts.
There are 2 options:
Use sandpaper or a Dremel to remove the teeth which fix the angles of the seat post. If you make it completely smooth, then you can use grip tape like that designed for a skateboard deck to add friction without locking you in to specific angles. This approach has ...
5
It seems everyone I know has a love/hate relationship with them.In other words liked it or didn't.My main complaint was while trying to maintain a consistant cadence I could feel the seat height changing.It seemed to interfere with my pedal stroke.Mine was an inexpensive telescope type,with no adjustments.My reccomendation would be stay away from the lowend ...
5
That is unlikely. The inside of a frame is machined/molded to a specific size for the seat post. An integrated post is not finished internally. Also, it is unlikely that the internal and external diameters of the post/frame/clamp would match well enough to be ridden safely.
Seat post fitting is a zero tolerance game, and they are dimension-ed to the tenth ...
4
The problem is that there is only one bolt holding the seat at the angle you want. Put enough torque on the back of the saddle and can overcome the friction that's holding the seat in place.
A few options:
Tighten up that bolt as much as you dare (but you've already tried that).
Increase the friction between the seat post and the bottom of the seat clamp ...
4
It's likely that Sheldon's concern was for galvanic corrosion between carbon fiber and aluminum. This is an issue that's well-trod in both the bicycle and aeronautics fields. In essence, in the presence of an electrolyte (sea air, your sweat) and a cathode (carbon fiber-embedded resin) the anode (aluminum) will corrode. In the case of a seatpost/seattube ...
4
Never use a hammer.
In order to check the inside of the frame, visual inspection most times FAIL, because the problem is caused by tiny bumps or misalignments that are not easily seen with naked eye and even felt with fingertips.
I would recommend that you take another seatpost (an old one you can take/borrow on a local bike shop) and try to insert more ...
4
Note that, in theory, suspension of any sort saves energy on a rough surface, since you "burn" less energy moving your own body up and down as you go over bumps. The negative side occurs, however, if the suspension absorbs energy as the pressure changes as you pedal -- ie, it goes up and down with each pedal stroke.
Again, in theory, a seatpost is least ...
4
Both seatposts you mention use an air spring, with a hydraulic release. There is no maximum weight listed for either one.
They are designed to use your body weight to drop the saddle when the remote lever is pressed, and to use an air spring to return it to full height the next time it is pressed. You need to be off the seat when the lever is pressed to ...
4
In addition to the seizure problem that others have mentioned, greasing the seatpost also prevents another problem: creaks.
I once spent weeks chasing down a creak that I initially thought was coming from the crank or bottom bracket. After disassembling and reassembling all that stuff, then tightening almost every single bolt on the bike, someone suggested ...
3
For greasing a seatpost you wouldn't use the same grease as for a bearing. For the seatpost you want a "clean" grease, and one that will stick well, not a grease designed to stand the extremes of wheel bearings. "White grease" or silicone grease would be options, or even a heavy oil. A hardware store will have options, if you describe the application. ...
3
Try to push the seat down slightly.The carbon weave can act the way those finger cuff toys we had as children did (the more you pull the tighter they get).By pushing down you release the grabbing action.Make sure you use something similar to Park Tool Carbon/Alloy Assembly Lube before you reassemble it,check with your local bike shop for their ...
3
The closest thing I have seen is the WeeRide Kangaroo that places the child in front of you. the support bar attaches to the seatpost and to the head tube, so if you had a second seat post you could leave the bar attached to that end and just connect it at the head tube.
I don't know of anything that attaches just to the seat post, as the physics ...
3
Cut the top off of the tube then carefully use a hacksaw blade inside the seat post to cut toward the seat tube. A handle for a hacksaw blade works or just wrap the plain blade with a bit of tape to make a handle. You should then be able to free the old seat post.
Or does the seat post extend way down into the frame? Even then this should help as the ...
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