Amt0571

Hello,

I have a recurring problem with my gravel bike. It creaks loudly. I've located the creak on the seatpost insertion.

If I remove the seatpost and clean everything, the creaking stops. The problem is that, as I ride the bike and the rear wheel inevitably throws dust and dirt towards the seatpost, it manages to find its way between the post and frame through the seat tube slit again (I assume that happens when it flexes while riding), and the creaking comes back in a few rides. I have never had this happen on any of my bikes... I assume that this bike having low seat stays has more flex facilitating dirt ingress.

I'm thinking of placing some tape that covers the slit under the clamp, but it seems really ugly. Is there a better solution?

hidetaka

Have you considered buying a proper frame with horizontal top tube and no dropped seat stays?
On a more serious note, there are 'seat tube dust covers' available from many online retailers.

Duragrouch

A piece of bike inner tube of the correct size should fit over both the seat post and top of seat tube. Experiment with sizes. I never toss old tubes, great for tons of things. Better than tape sticky residue on there. I think I've seen these on many bike fridays at the juncture of the telescoping seat tube.

Also though, aluminum on aluminum often produces "aluminum spooge". Aluminum anti-seize might prevent that, but also cause your seatpost to slip.

But I like the horizontal top tube suggestion, I'm a retro-grouch on that for road bikes.

Ron Damon

Grease has solved my creaky seatpost problems in the past.

Mackers

The squeaky seat post gets the grease.

masi61

I doubt that dirt infiltration is the main reason for the creaking. If the post you are using is even slightly undersized or the bore of the seat tube slightly oversized the recurring creak problem will continue to recur. I suppose since it is a gravel bike the height of the post if there is a lot exposed will expose the issue sooner. Amt0571 would you mind sharing info about your frame, what seatpost and what seat collar you are using? A picture or two would help as would some metric caliper measurements dof seat tube bore and seatpost diameter.

Amt0571

Unfortunately, I don't want a gravel bike with a dropper post.

The bike is a Triban RC520 GRVL. The seatpost and collar are the stock unbranded ones sold under the Decatholon brand, I'm not sure who manufactures them. Nothing seems out of tolerance but I'll measure it just in case. It's a cheap bike, so probably quality is not the best... I also have dirt ingress issues with the derailleur cable housing because the outer end caps are low quality, but that's easy to solve. In any case, it rides good and is more that decent for its price.

It's this bike:


I don't like dropped stays nor do I like the tight tire clearances, but I bought the bike for 600€ in like new condition while normal price was 1100€ (it even had the original brake pads and tires with no measurable wear) and it was simply too hard to pass.

Iride01 

Curious as to what you notice that makes you not like the dropped stays.

If the tire clearance isn't enough, put narrower tires on it.

Bike was used or NOS? If used, are you certain it has the original seat post. If a seat post with a narrower diameter was put in, then even with the clamp being able to hold it at the top of the tube, the end of the seat post might be rocking back and forth in the seat tube making your noise.

Though realize there is always the chance the noise might be something else that just solves itself incidentally to your actions taken each time. It could even be sweaty bike shorts rubbing on the nose of the saddle when any dressings or stuff you might use to clean the saddle wear off.

force10

[QUOTE=Amt0571;23246391]Unfortunately, I don't want a gravel bike with a dropper post.

Are you saying that your seatpost isn't greased? If so, that is almost certainly the problem.

masi61

Greasing a seatpost with thick high quality grease should help it stay put and be quiet. You could also use carbon fiber grip paste to allay your objection to grease. You didn’t mention if you are tightening the seat collar bolt with a torque wrench and to what torque setting. A low quality seat collar could be tuned up a bit - make sure the orifice for the Allen head cap screw gets lightly greased as well as greasing the bolt threads and the threaded hole in the seat clamp body. If these were dry previously, you may not have detected that the seat clamp was not sufficiently torqued to prevent a recurrence of the creaking noise. Is the seatpost a 27.2?

Amt0571

It's identical to the seatpost new bikes had on the store. Bike was apparently very lightly used and returned with few miles after less than 15 days. The original buyer bought it when there were no bikes in stock and, considering he replaced the stem with a really long one, it seems the problem was that it was not his size.

[QUOTE=force10;23246482]No. It isn't greased. I only use carbon paste on carbon posts, which is not the case. I've never had a seatpost creak. I've had greased seatposts slide like mad though.

I'm currently not sure about the seatpost size. I'll try carbon paste. It's torqued to 6nm using a torque wrench.

smd4

Agreed--you need to grease your seatpost.

If it slides--there's a bigger problem.

Duragrouch

Yeah I don't know about greasing a seatpost. If I needed to, I would use (aluminum) anti-seize, it has what feels like a grease base, but the very fine metal powder is supposed to put back some of the friction, while still having the other benefits of grease, such as eliminating squeaks, corrosion, and seizing. However, either one would be a huge mess on my folding bike where the seatpost slides up and down like about a half meter. But a bit of anti-seize on the sliding surface of the external-cam seatpost clamp, made a big difference in lever force versus clamp force. I do also put anti-seize between the steel frame and (fixed) seatpost bushing/sleeve, but not between the bushing and (moving) seatpost.

And like I said, a piece of inner tube will keep that clamp joint a lot cleaner. In fact, though I haven't had problems like you have, this has motivated me to cut a piece of tube to fit my bike, I don't need to fold it often, and that'll keep both grit and water out of the bottom bracket shell. My guess is there are commercially made covers out of wetsuit material (neoprene foam sheet?) that velcro in place, easy on and off.

smd4

You realize greasing the seatpost is standard shop practice when building a bike, right?

Koyote

Seems like the OP doesn’t know this, either.

Duragrouch

I did not. I can see the reasons. I think old smooth chromed DOM steel posts might slip with grease, but evidently not modern aluminum ones.

As I said, grease or antiseize on a long seatpost on a folder would be a nightmare of a mess. Fortunately I have no corrosion, galling, or squeaking issues there. If grease was needed there, I guarantee you that someone would rapidly invent and produce, an accordian-bellows-style shield to contain the mess, those are used commonly on many products these days and there may even be off-the-shelf material available, needing only to cut to length and band clamp at top of seat tube and top of seatpost.

smd4

They didn’t.

I know nothing about folders and how messy their seatposts get.

Duragrouch

Well, my folder at my seat height, there is 17" of exposed seatpost and about 6" inside the seat tube, with almost the entire seatpost descending when folded, about 10" of that then sticking out below the frame. So all that up and down would put grease everywhere on hands and anything else the seatpost touched. A bellows on top and bottom of the post could solve that, but fortunately, currently a solution in search of a problem, the post moves fine without grease. However, a carbon post that required friction paste to not overtorque, that might be needed. I avoid carbon, but there are tons of folding bikers who install every carbon bike part known to humankind, in search of lighter carry weight, a totally valid consideration, and seatpost is the biggest weight saver among them.

Ron Damon

That's right. A greased seatpost that slides points to a separate, different problem. If the seatpost collar, seatpost and seat tube are all in good shape and in the correct size, there is no reason why a greased seatpost should slide.

Ron Damon

I told you so. The greasing the seatpost bit.

And no, grease on a long seatpost on a folder need not be a mess.

Ron Damon

Trust me, they need not get messy when greased.

bboy314

As others have mentioned, metal seatposts should absolutely be greased. Since you say the creak is definitely coming from the post, I’m willing to bet that’s your problem.

sweeks

That seatpost does not look greased; if it is, it's a very thin layer and very recently done.

veganbikes

Grease, anti-seize or fiber paste along with proper installation and torque is crucial to a non-creaky seatpost (assuming seatpost is correct size)

smd4

That seat tube is 6” tall; how much do you think the exposed seat post should be greased??