sweeks

On a folder, the seatpost goes up and down... a lot, if the bike is used for commuting. For example, my folder's seat is re-positioned 4 times a day, 5 days a week. Grease anywhere would soon be everywhere, and a risk for getting on my work clothes. Also, a lot of seatpost slippage problems on folders can be traced to inappropriate use of grease.

Ron Damon

This is what it looks like essentially ungreased. It had just been cleaned after a tour for the residual grease does attract dust and pollen.

You see that plastic grommet at the base of the seatpost? That is what one uses to keep the grease from coming up on the seatpost when raising it. It's a $0.50 part. You also use clear (looks yellowish in bulk), lithium grease. It's not rocket science or brain surgery. But it is metal on metal surfaces that slide against one another. ​​Of course, it is, it should and it can be greased.

You are of course free to leave it ungreased at the expense of increased wear on the micro ribs seatpost. The seatpost is only a $7 part so it's not a big deal to replace, say, every year. But make not mistake about it. The seat post can be greased without making a mess and show zero slippage at the same time.

Ron Damon

This is a straw man for we are not taking about seatpost slippage on greased seatposts. We are talking about creaking on ungreased seatposts, the OP.

Once again, seatpost slippage is not in the first instance a problem due to grease. If the seatpost slips while greased, you have a separate, distinct problem. If the seatpost, seatpost collar and seat tube are of the correct size, shape and proper working condition, a greased seatpost will not slip.

sweeks

I completely agree; no "strawman" intended. I was trying to explain why greasing a 6" seat tube on a frequently moved 2' seatpost is not a practical solution.

EDIT: I see the previous post. Feel free to grease your seatpost. I'll continue not to grease mine. The anodizing does eventually wear a bit, but there's no problem collecting dust or pollen, and I don't get grease on my hands or clothes. In 14,000 miles I replaced the seatpost once because it broke where I had scored it for location purposes and created a stress riser. In those miles, the post never slipped.
As my dad used to say, "One man's meat is another man's poison."
Cheers,
Steve

smd4

I don’t think so. That seat tube is 6” long. What are you going to do, raise the post 2 inches?

Amt0571

I finally greased it with carbon paste and today I'm going to check if it still creaks... I'm not going to put normal grease there. I've already done that twice on my life and in both tries it resulted on a slipping seatpost no matter what.

It's not a good idea to grease a folder seatpost. I'm talking from experience. My folder however, had an aluminium sleeve between the seatpost and the frame, and I greased the sleeve/frame contact area to remove a creak.

sweeks

Sorry for the confusion. We got a little off-topic onto folding bikes. The OP's bike has a much shorter seatpost.

When this bike is folded, the saddle is just above the frame tube.

sweeks

This is my point of view, also based on experience. I have addressed creaking from the seatpost in exactly the same way you describe.
I'm in the process of building up another folder with the same frame. However, this new frame has a seat tube liner of some sort of plastic in place of the aluminum sleeve.
I'll be interested to see how this performs, from noise and durability perspectives.


This seatpost is not greased.

Amt0571

I had a Dahon that had a plastic sleeve. It was crap. It got deformed with use, making it slightly thinner as the plastic got somewhat compressed, until finally the post slipped unless I applied a huge amount of force on the seatclamp. I eventually replaced it with an aluminium sleeve from Tern and there were no further slippage problems.

A few years later the bike developed a couple of cracks on the seat tube slit. I can't prove it, but I have the feeling that the crappy plastic insert had something to do with it.

Nice bike BTW. I don't have a folder anymore and are not up to date on them, but check the frame carefully because some years ago Terns were famous for breaking in half at the hinge.

Duragrouch

None at all. But if greased at the seapost collar or seat tube, when folded, the seatpost goes way down, contacting the grease, then up, then down, then up, etc. Very quickly I think, it will have a grease coating, not very thick, but there. I'm not condemning the practice of greasing, but I think there's no denying that most of the post will get grease on it, then on my hands (I don't lift by the seat since ripping one apart by lifting on the rear, it ripped the plastic base off the rails), and my clothes when carrying up stairs, the seatpost is against my right ribcage when lifting by the top seatstays.

smd4

I'll say it again: If your seat post slips when it's greased, then something is wrong.

Amt0571

Then I've had too many bikes that had something wrong. Probably all of them.

smd4

I really don't want to get into a discussion of folding bikes, which I consider nothing more than novelties anyway, like unicycles. The fact of the matter is, the OP's seat post is creaking more than likely because he didn't grease it.

smd4

I was trying to avoid saying it was operator error, but...

Amt0571

Well, I'm using a torque wrench and I have always torqued seat clamps to spec. In fact I have 2 torque wrenches, so I'll be really happy if you can tell me what I'm doing wrong. Unless I happen to have 2 bad torque wrenches...

smd4

I have no idea what you're doing wrong. I'm not telepathic. I can't see your bike; I can't measure your parts.

Along the same lines, maybe you can explain to me how 12 trillion bicycles in the world* with greased seat posts/tubes DON'T slip?

*Merely a guess.

Duragrouch

I'm just gonna step back and put on helmet, ballistic vest, athletic cup, and dive for the blast shelter on that one. You'll see.

Crankycrank

Why not just use a wax based lube for the post on folders? Doesn't get messy and provides the lubrication needed. Of course, would need to be reapplied every so often but pretty quick and easy to do.

sweeks

One man's Novelty is another man's Staple.
I've been commuting on folders for over 20 years (~25,000 miles), and have done two Centuries on them.
Hmph... "Novelty"... Hmph.

(H/T: Duragrouch!)

smd4

That's cool.

People do all kinds of weird things that most of us wouldn't:

Unicycle Century

sweeks

I had the same problem on both my Dahons and the Tern, all of which had the aluminum sleeve. My hypothesis is that the stress breaker holes at the bottom of the seat tube slots were too small (inadequate radius of curvature) for an aluminum alloy frame.
On my Dahon Mu XL the cracks completely circumnavigated the seat tube before I noticed them. I could lift the saddle and seatpost off the bike, including the top of the seat tube and the clamp. Luckily, this was a "Fail Safe" situation. I made a couple of stays out of aluminum to hold the clamp down; I got several thousand miles out of the bike after that.
When it started to happen on the Tern, I did what I should have done for the Dahon: I increased the diameter of the stress breaker hole considerably. No further crack propagation.


Here's the "winter" bike. The fully-separated top of the seat tube and the "stays" may be seen. The rough edges of the fracture kept the saddle from rotating. :-)



Dahon handlepost with the same problem. This is NOT a "Fail Safe" situation. Several years of service without further propagation of the cracks.


Modified stress breaker hole on the Tern. The marks to the left are from the Dremel tool slipping. The aluminum sleeve may be seen.

Thanks! It will be my "good weather" bike when it's finished. That frame problem is in the past, as far as I'm concerned. I *did* have the original frame replaced during one of the recalls, though it didn't show any sign of impending failure. Better safe than sorry!

sweeks

I saw a guy on a Century riding a mountain bike without a saddle. Standing the whole way.

smd4

Let me tell you, that was the worst ride of my life! Talk about death from below...

Duragrouch

Dahon crack at tube slit:
- Plastic bushing so clamping would deform tube more, adding stress. Redesigned with aluminum bushing which both doesn't compress, and reinforces joint. I'd like it even better if they made a stainless steel bushing, that would have 3X the elastic stiffness as the aluminum one, at very small weight penalty.
- Slit and lower radius on front of seat tube, loaded in tension under aft seatpost bending force, more susceptible to fatigue failure than compression. Redesigned with slit and radius on back of seat tube, loaded in compression.
- Aluminum frames have additional gusset at top front of seat tube and top tube, and slit at back, but still can fatigue crack at juncture of weld and seat tube; A well-dressed and radiused weld (like on a Cannondale) greatly reduces stress concentration there, much better fatigue life.
- Introducing residual compressive stress to edge of radius at bottom of slot, like burnishing with something round of hard steel, helps fatigue strength there (this is after removing any cracks there, if present).

Duragrouch

Regular bikes with seatposts clamped in place for years at a time and not moving up and down frequently, grease or anti-seize makes complete sense, to keep them from seizing in the seat tube.

But for a folder with a post that is frequently moved up and down, any lube is a solution in search of a problem. Plus, that movement is with the clamp open, an easy slip fit, so shouldn't wear seatpost.

I know, the issue is squeak, which can also occur on a folder, perhaps even more likely because the seatpost is so long. Still, squeak requires movement, my guess is tilting fore and aft under pedaling; Mine doesn't squeak, but if it did, my guess would be due to an order of magnitude higher seatpost moment for the same weight, compared to conventional bike. The clamp bushing is short in relation to the amount of seatpost inside the seat tube, which means the bottom of the seatpost probably moves, in fact I find evidence of that on the front of the seatpost there, where it's been rubbing on the seat tube inside front (although that could be a remnant of the previous frame with plastic bushing). So I would try glueing on several layers of soda-can-shim material there, or perhaps self-adhesive aluminum body repair tape, to build up close to the seat tube inside diameter, as that may greatly reduce seatpost movement, both reducing or eliminating squeak, and also better durability of everything there. I may do this for mine.