Ev0lutionz

Am I doing this right? Using GT85 on the seat clamp to de-rust, cleaning the old grease on the seat post and frame and then re-applying teflon grease to the post and frame.

My frame and post are aluminium.

Crankycrank

Yes, perfectly fine. You also don't need any special grease as it's not for lubrication, just corrosion protection. I like to remove and re-grease every 2 years or so just to make sure it doesn't corrode which is probably overkill but 15 mins of time every 2 years is better than a fused post.

Sy Reene

I'm guessing the seatpost is still slipping? Or are you asking if what you're proposing to do should work?
What torque value are you tightening the clamp to?
Instead of grease, consider using assembly compound (eg. Park SAC-2) to help with slip prevention. Just put some inside the seat tube as far as your finger can reach. Be a bit careful as this stuff can induce scratches -- you'll want to ideally pre-mark (eg. with tape or something) where you'll want to insert the seatpost to, so you're not going up and down with the assembly with the assembly compound smeared on it while you figure out the correct height.

freeranger

Carbon "paste" will help keep it from slipping. I've also used anti-seize, made for auto spark plugs, since I had some on hand.

grizzly59

If you can get a bit of rock polishing grit that feels fairly fine to the touch, you can mix with grease for DIY assembly paste. Or use grease + ground up grill charcoal.

Iride01 

I'm wondering too like Sy Reene . Is your seat post actually slipping or are you just worrying about something that might be nothing?

Things to look for are if the gap in the clamp closes up completely or even the gap on the seat tube closes up completely. That might indicate you have the wrong size seat post or clamp.

Grease? Anti-sieze? Nothing? I have done them all, and I've never had a stuck seat post in 50 years. Never had one slip that wasn't the clamp gap closing completely. Or the clamp bolt fractured from over tightening but not completely broken.

Carbon seat post and seat tube? I don't know. Just got one a little over a year ago. They say to put carbon assembly paste on them to help keep them from slipping. Sounds reasonable to me, I'll do that when it's needed.

Don't be ham handed tightening them whether carbon, steel or aluminum. Too much is worse than too little. Too much will either break your clamp bolt or stretch and distort something. Too little will let your seat post slip. But at least you can tighten it a little more till it stops slipping.

3alarmer 

...the chances of an aluminum post getting seized due to corrosion an an aluminum alloy frame are somewhat reduced because there's little galvanic corrosion potential.


If it is slipping (you haven't said), and it's the original post that came with your frame (i.e. correctly sized), you can reduce chance of slipping by applying grease only down in the interior of the seat tube, down past the clamp. You do this by cleaning off the post and interior clamping surface with mineral spirits or acetone, then applying some grease or anti-seize with your finger, down past the clamp. As the post slides in, it should spread it around down there.