buchro

I've read that greast helps prevent rust and keeps the post from "freezing" in place.
As a casual biker, will I really need to adjust the seat height? Is the point that the
seat may slip down and then freeze in a spot that's too low for my body?

GlennR

If you have a carbon fiber bike, it won't rust.

cb400bill

Over time, metals like an aluminum seatpost and a steel seat tube can fuse through oxidation or bind through friction. Simply applying a coat of grease between the two provides a barrier against corrosion.

https://www.missionbicycle.com/blog/...st%20corrosion.

ofajen

So it won’t make a mysterious creaking noise when you are pedaling out of the saddle.

Otto

Maelochs

I have heard it called "galvanic welding" or something .... but a seat post can bond electrically with the seat tube, and you will go through all kinds of backyard mechanical improvisations and uncivil vocabulary exercises before you get the sucker free ... and sometimes you will do irreparable harm in the process.

From what I hear .....

sdmc530

I too have only heard of this phenomime…..sound like a terrible situation....or so I have heard?

wolfchild

I have steel and aluminium bikes which have 13 Canadian winters on them and none of my frames are rusted or corroded yet. I did spray some rustproofing oil inside my steel frames and never had an issue with corrosion.

wipekitty

I've heard about this as well...in fact, a "friend" told me that they once had to take their bike to the LBS to get it unstuck, at which point the mechanic sold them a giant tub of grease

cubewheels

- To prevent/minimize "galvanic" corrosion if your seatpost and frame happens to be two different metals (like steel and aluminum).
- The chance you might bend the seatpost for any reason even if very slightly/unnoticeably bent, grease would prevent it from getting stuck in place.

Even for more serious cyclists, once the seatpost is adjusted to fit (and after much testing), it's not adjusted anymore (like never) but still, grease on the seatpost remains important.

IGH_Only

What if you have a carbon seat post with an aluminum or steel frame?

Koyote

Even if I don't have any other reason to pull a seatpost from the frame, I will do it every year or two in order to reapply a thin film of grease. It's cheap insurance.

veganbikes

Because every single mechanic on the planet will want to kill you for allowing parts to seize.

For aluminum or steel posts in aluminum or steel frames use grease
For titanium use anti-seize/copper paste
For carbon posts or posts in carbon frames use carbon paste

Don't let your seatpost or any other parts get seized on any of your bikes.

SurferRosa

If you ride it over a long period of time, yeah.

When you get over 50 years old, some days you might feel taller than other days. If you're riding over 30 miles, a half centimeter in height change becomes a big deal. Furthermore, as a 50 year-old, when the season begins, you might feel/ride shorter than at the end of the season when you're in your best shape. Years later, as your skeleton shrinks, seatpost height should as well.

An 8oz tube of white lithium grease at Lowes is like $5.

OldTryGuy

Personal experience required a total frame stripping, soaking with Blaster and then clamping seat post in a vice and twist.

Different frame materials requires different compounds, or not.

indyfabz

The real question is: Why not do it?

dedhed

https://www.bikeforums.net/classic-v...-seatpost.html

Moe Zhoost

Never have to adjust a seat post? This is dreaming. I have to drop my saddle to prevent interference when transporting 2 bikes on my platform rack. Even if you don't have to do this, a change of saddles, pedals, or shoes will have you making small adjustments. Stuck seatposts are not common, but so easy to prevent with a dab of grease. Just do it!

schind1324

A small amount of grease will help prevent the post from sticking in the frame. It actually helps keep it tighter also. I was a bike mechanic in my younger days and we greased the posts of every bike we assembled.

gecho

A guy I know bought a used steel fat bike. He needed to use lye to dissolve the old seat post to get it out.

coffeesnob

if it gets that bad a little kroil and a pipe wrench will unfreeze it

noglider 

You may think you have it set at the right height, but much later, you may need to change it. You may discover it's been too low or high for years. Or you may want to loan your bike to someone. You may want to sell it or give it away. You may want to take the seat post and seat out to jam it into a cramped car or other small space. Grease the seat post every year to prevent this problem.

Gresp15C

Amusing anecdote: I went to a bike auction a few years ago, to raise rent money for the bike co-op. I bought a couple bikes for parts. Two or three of the people, including me, had brought a small number of tools and were checking seatposts. A stuck seatpost meant the bike went back on the pile, no bid.

bg18947

Specifically lithium grease creates a barrier between aluminum and steel (iron alloy). Whenever the outside electrons of two elements adds up to 7, an ionic bond occurs (galvanization). Same reason why you put Never-Seize on spark plugs.

JohnDThompson 

Perhaps at some point you will replace the current saddle with one that has a slightly different rail-to-saddle-top distance. Or perhaps you will suffer an injury or age-related change that limits your knee range of motion, requiring a shorter crank arm and different saddle height. Perhaps you want to sell the frame to someone else who needs a different saddle height. And so on…

Reflector Guy

The same phenomenon happens with modern automobiles and their aluminum suspension parts too. Ever try to replace a wheel bearing hub in an aluminum steering knuckle, if you live in the salt belt? I've had to remove the steering knuckles from the car and chisel out the bearing from behind a few times. This was never a problem on older cars with steel (or is it iron?) components. The dissimilar metals we see now react with the moisture and salt almost as if they've been welded together.