crack in the paint or crack in the steel?

[Paul Schlumberger]

Hi everyone,

I just received my Sam Hillborne frame bought second-hand and noticed a crack just under the back of the seat post lug.

Though I hate to admit it, it looks like a crack in the steel. There are two thin dark lines visible from the outside, and a sort of 'dent' inside on the opposite. I am attaching pictures.

Can anyone from the group second my guess? Did any of you have a similar case on one of your Riv frames?

And what would you do in my situation? The person I bought it from hadn't noticed it and was riding the bike fine despite the crack. Should I just put a long seat post (which reinforces the area anyway, unlike a cracked head tube or bb shell) and ride the bike like this?

I can't yet imagine bringing it for repair at a frame builder because buying the frame in the first place was quite a stretch in budget for me.

I'd love to hear your thoughts and advice!

Cheers,

Paul

[Doug Van Cleve]

Hey Paul.

From the pics, it looks a bit buckled to me but I’d be surprised if the steel is actually cracked.  I don’t think I’ve ever seen such a thing before… The only scenario I can think of, or something like that could happen is if the seat post was only inserted into the lug, down about to where it looks tweaked?  Weird.

I agree that renting a seat post that extends well below that area should be perfectly “safe” and should ensure nothing else happens.  I guess the question is, are you OK with it?

Doug

Chandler, AZ

[Paul Schlumberger]

Hey Doug!

Thanks for your answer. I'm definitely fine riding the bike like this. Indeed with a seat post in the tube the area is reinforced and for sure there won't be any surprise accident because of the crack.

I want to make sure to even identify it as a crack in the steel instead of just the paint because I don't want rust to start eating in further. What did you mean by buckled? And by that 'nothing else happens' do you mean, safety wise or in terms of the crack developing?

To me it looks like there was a hit on the nose of the saddle once, and the back of the seat lug received the pressure.

Paul

[Steve]

Paul, I don't know....as I zoom in on your picture showing the rear of the seat tube it starts to look suspicious. The tube is definitely rippled below the lug with two visible cracks in the paint and possibly some distortion along the length of the tube (?).  Doug's thought that the bike may have been ridden with a seat post inserted to a shallow depth would seem to fit. 

I'd probably mount a seat post inserted just to the bottom of the lug and then inspect the cracks closely while manually levering it fore and aft, looking and feeling for any sign that they might be opening up under the pressure.  Regardless, using a long seat post sounds like a good idea. 

Steve 

[Kainalu V. -Brooklyn NY]

Remove that paint as it’s the only thing that’s definitely cracked. That way you’ll get a clear view of what’s underneath and there’s not a place for water to get trapped. Probably get it most of the way gone with a toothpick.

Be the bike dentist 🦷 

-Kai

[Jim M.]

I'd ask for a partial refund. That's a flaw that should have been disclosed, though apparently they didn't know about it.

jim

walnut creek

[Ben Miller]

Agree with Jim, but I'd ask for a full refund and return. If no, then I'd ask for  partial refund.

I do think it's ridable like that, but it does look cracked to my eye. Replacing the seattube might be prohibitive expensive, but if you have a local framebuilder who does repairs, I'd still take it to them. Maybe there is something they can do to at least relieve the stresses. Cracks by there nature are stress risers and without some sort of relief they are likely to keep growing.

Ben

[Jason Fuller]

That's a bummer situation for you and the seller both. I would ride it without concern unless quite a heavy rider, but agree that is more than just paint. It's certainly fair to ask for a partial refund to help cover the cost of repair if it ends up needing it - I am imagining you would rather build up and ride this bike than return it since you're probably very excited to have gotten it!  I'm not an expert on this but it doesn't look super likely to propagate to me - looks like maybe the previous owner came down hard on the saddle over a bump and the downward force exerted through the seatpost clamp buckled the tube a bit.  

[Corwin Zechar]

I would send good pics to Grant. The second photo (from behind the bike) is an example of a good photo. First photo is out of focus.

If Grant says the frame is OK, I would not worry. If he says it is compromised, I would get the frame fixed.

Dickering about refunds, accommodation, etc. comes after determination of the damage.

Regards,

Corwin

[Doug Van Cleve]

It’s a bummer, for sure.  IMHO, the seller not knowing/noticing doesn’t mean much (if anything).  I assume this was not cheap, and I highly doubt any repair would be less than $500.  I’m not sure a seat tube can be replaced and not require a full repaint, and nobody does cheap paint (that you would want) any more…  I don’t think it is unsafe, assuming a correct fitting seatpost that extends well below the sketchy looking area, but will you be okay with that on your dream bike?

Regards, Doug

Chandler, AZ USA

P.S.  By buckled, I meant the tubing appears to be distorted in addition to any paint cracking…

[Mike Rossi]

I agree with Kai. If you don’t get rid of the paint, you’ll just be guessing. I’ve been an automotive painter for over twenty years, and I’ve seen paint cracking like that with nothing wrong with the metal underneath, besides some surface rust (or some seriously pitted rusty metal. Just depends on how long it’s been getting moisture in there). I know what I’d do, but I’ve got experience with body work, welding, painting, etc. 

Best wishes.

[Garth]

If you do want a frame builder opinion after removing the paint and better photos to looksey, I'd contact Jack of Franklin frames in Ohio. He's done countless repairs on frames and builds custom himself. 740-763-3838 

[Paul]

Hi there,

Thank you all for your concern!

@Steve, Kai, Corwin and mwillrossi, Garth

I pick out from your answers that until I remove the paint around the crack, damage on the frame is just speculation. I agree, that's what I'll do and I'll send pictures to a local frame builder here in the Netherlands. In the meantime, I will still build and ride the bike like this. 

@Jim, Ben, Doug,

I am super bummed for sure but would rather accept to the situation than ask for a refund. It is what it is, as they say. I bought the frame blind and the seller was both honest and available when we planned a scheme to have it brought back to Europe. It was packed perfectly well and he told me he had never noticed the crack while it was his.

I also went looking at pictures from the previous previous owner and it looks (though it's hard to see) like the crack was there already then. It seems the bicycle has been ridden 'damaged' for more than a few years. I hope this indicates that things are better than the worst I imagine. Picture attached.

@Corwin, the first photo was to show the dent, which appears as a white strip, inside the tube! I'm not sure what it indicates but it's there, going slightly inwards, on the opposite side of the tube wall from the mark.

Anyways, I will keep this thread updated if anything new is revealed when I removed the paint. I still look forward to posting a picture with the bike built!

Best wishes,

Paul

[Mackenzy Albright]

Thinking about any sort of buckling there melts my brain a bit. The front of the lug is supported by the top tube. The lower top tube, I'd assume, would make the seat tube incredibly rigid. Seat tubes themselves are usually one of the thickest tubes, no? Not to mention the seat stays would triangulate the lug even further. In the instance of an improperly inserted seat post I can't fathom enough force to damage it at that position in the lug. Not saying it's not possible but it seems odd. 

Given the complexity of the lug junction - maybe the paint has pooled slightly making it thicker and appear warped. The shine makes likely exaggerates the effect? I am itching to see what the area looks like sanded back. My orange Clementine had atrocious paint and cracks everywhere. So many bald patches just to double check. 

I really hope for a follow up :) 

[Edwin W]

Paul,

Sorry to hear, as we all love Rivendells and all hate to see an imperfection in such perfect bikes!

That said, I would:

Sand down the area so that the metal is exposed and you can really see what is going on as others have said. 

If a seat post can be inserted past the imperfection, I do think that will increase the safety greatly.

If I owned a bike company, and someone bought a bike my company made second hand, and asked me if they could still ride it with that imperfection, I would not want to issue an opinion! So, I don't think I would put that pressure on Rivendell - their involvement is too far removed, I think... but I will be interested to hear what others think.

Please send us updated pictures and tell us what you do.

Edwin

[Ben Miller]

Mackenzy wrote: " Seat tubes themselves are usually one of the thickest tubes, no?"

Seat tubes are tend to be thick at the bottom, close to the BB. They tend to be thin at the top, near the seatpost. See Reed Kennedy's compilation of tube measurements for some Riv and other examples (No, Sam H though, unfortunately). Hope that helps.

[Nick Payne]

On Thursday, 27 March 2025 at 3:47:00 am UTC+11 Mackenzy Albright wrote:

Seat tubes themselves are usually one of the thickest tubes, no?

Not at the seat lug end. Seat tubes are frequently only single-butted, with the thicker butt only at the bottom of the tube where it meets the bottom bracket shell. The inserted seatpost provides extra reinforcement at the top. With a normal 28.6mm OD seat tube, you can easily figure out the approximate seat tube thickness at the seat lug by subtracting the seatpost diameter from 28.6 and halving the the result. So a frame that takes a 27.2 post has a wall thickness there of ~0.7mm, with a 26.8 post it's ~0.9mm, etc.

Here's a selection of seat tubes from the Columbus catalogue. All the 28.6 OD tubes they show there have a 0.6mm wall thickness at the upper end.

Nick Payne

[Jason Hartman]

You need to account for brazing/welding distortion, and also a little wiggle room. High end 28.6 seat tubes such as Columbus sl were .6mm at the top. The inside diameter is 27.4, but you leave a 0.1mm gap all around so the 27.2 seatpost slides in easily. 

Jay Hartman

--
You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bun...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/0e827113-3775-4a11-bc57-0d6b115f2eefn%40googlegroups.com.