I bought a used gravel bike. While looking at the parts to see if there's anything to be maintained etc. I noticed that there's a lot of wear on the seat tube. I didn't yet notice what actually causes the stripes seen in the picture when one would change the seat height (something sharp in the seat tube clamp causes the scratching when the height is changed?). But I'm honestly curious in general why would someone do this to the seat post? Looks like it's been but up and down times and times again. Maybe they needed to take of the seat because of transport in a car or something?
by justville
16 Comments
Seems like the saddle got moved up and down without loosing the saddle clamp enough.
It’s been in and out a lot. Time to bin that and get a new one.
seems like someone had the opportunity to choose grease but has chosen violence instead
You should always grease your pole before sticking it in the hole!
Check the seat tube for any protruding edges. If the frame is made from steel/aluminium, file the edge smooth, e. g. with sandpaper or a rounded file.
Is it carbon ?
Probably because of transport or maybe something else. Its most likely scratched by sharp edge on the slit of your seat tube, so you could take small file and pass over the inner edges with it few times. Not much just to take of the sharp edges, like one to three passes should be enough
Nah 99.9% it’s not the frame or something like that, dude just adjusted the seat up and down without completely loosening the clamp. I’ve seen a ton like that. It’s probably still safe but sure looks like shit, so maybe consider changing it.
Need to inspect the seat tube of the frame.
Inspect the area for any debris that could be causing it.
If that’s free, have a look for imperfections in the casting of the frame.
If you see any, and the frame is metal, feel free to take a rounded file and file it down.
It looks like there is some kind of burr on the inside of the seat tube that caused these gouges, and that someone worked the post in and out and side to side several times trying to free it up.
I’d get a new post but first, figure out where that sharp edge is and knock it down with a file or something.
That post has just be regularly twisted left and right to move it up and down, but without properly unclamping the post. It’s still been semi-clamped when moving it, hence the need to aggressively twist it left and right to get it up and down.
Some animal really needed a dropper post, but didn’t have one.
Probably fine, but a potential point of failure. For what a seat post costs, I’d probably get a new one.
Pretty common scratch to see. Even with the clamp fully loosened or removed sometimes the edges of the slit in the seat tube will scratch the post as it gets removed or inserted.
I’ve sanded a couple bare aluminum posts to smooth out the scratches enough for them to slide in fairly smoothly and not look horrendous. Hand sanded with 150grit to knock stuff down and then 400 to finish. You’re never going to get a scratched post perfect looking without removing so much material that the post would no longer be the correct size but removing the little bit of metal that got pushed up to the side of the scratch is possible.
In this case I’d say to just consider a new post since I imagine you’d want the seat post to be black as it probably matches the bike. Make sure to sand or file the inner edge of the seat post slot before you put a new post in (assuming Aluminum or steel frame)
There’s either a burr inside the seat tube from when the bike was manufactured or there’s a bit of grit lodged in it, or the seatpost is originally off a different bike with a similar problem. As to why it’s been done so frequently, could be many reasons. It could’ve been swapped between different bikes a lot, maybe, or one bike that’s used by different height riders a lot. Back in the day, before dropper posts, we’d use QR seatpost clamps to raise the post for climbs and drop them for descents, so it could be an old post that’s been used for that.
https://preview.redd.it/cakqvyzr8p2f1.png?width=1396&format=png&auto=webp&s=e405563c6cd2e4c21b2d535d36a0f963c84893fc
Seat tube probably needs a little TLC with one of these, probably a sharp edge where the split is.
Guy took it off every time he locked it up …. Expensive saddle I’m guessing
could be a case of parts bin part for the sale and keep the nice part for myself