mkemmer1

My bike is 19 years old, Reynolds 853, but hasnt gotten much use the last few years. Was going to put new parts on but shop says they noticed this crack - bottom of seat tube by BB

What do you think - is that a crack? Would you build it up and ride it?

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AnkleWork

You'll have to clean it to bare metal to know.

Homebrew01

What wore down the paint ?

Doesn't really look like a crack. Ride it, and keep an eye on it.

sch

Looks like a rust bubble popped off the paint. Suspect that a significant thickness of what was steel is now rust in a 10-12mm diameter area.
I would suggest at least pulling the BB and seat post and eyeballing the insides of the tubing so see what else might be going on. Frame is
safe to ride but its value just dropped a lot. 853 tubing was probably butted, so this will be a thicker part but one reason for 853 was
strength and hence thinness, so you might be dealing with an area where the tubing thickness was under 0.06" to start with.

A google on 853 Reynolds tubing pops up a wiki article, pretty impressive stuff. From the pix, your frame was butt welded, don't see
any evidence of lugs.

LifeCycles

+1. When a crack develops in this area the frame typically won't catastrophically fail it will just be really flexy and you might hear scraping noises as chain alignment and things like that get out of whack.

FBinNY 

This is a simple economics question and turns on what building it up will cost you. For the moment, assume it is a crack (I'm not convinced it is). So the frame may last another year or two or it might last two weeks. If building yourself I'd go ahead, because you have nothing to lose, but if paying for a build, you need to decide how much life you need to get value from the outlay. Unfortunately there's no answer anyone here can give you, better than my 2 weeks or two years.

As for safety, I agree with others that the main hazard is inconvenience, especially if you live in a hilly area. If it cracks completely, it will still be safe to ride, but will only tolerate very light pedal pressure. If you're creative you can make emergency repairs to get you home, so even the inconvenience can be mitigated.

As for know whether it'a crack or not, the only way is to sand the area to bright bare steel, and use a contrast die to bring up the crack, and make a judgment call. If you have a friend who does "magneflux" he can give you a definitive answer over a few beers, but a commercial price might be more than the whole deal is worth.

cale

Looks like a crack to me. Failure in the region of the bottom bracket is fairly common and can be fixed but it's going to mess up the paint.

unterhausen

it looks like a crack, and I really don't think it would be worth trying to fix. But you can sand down that area to make sure. It's a little strange that the crack looks so well formed, but isn't longer than that

kunsunoke 

The quickest way to get the rust and paint off of the area is media blasting. Not an option for most folks, I know. So you'll probably want to start with 600-grit sandpaper and clean it up as much as possible.

If there is a crack, the frame's going to have to be repaired professionally, since it's made from the Reynolds 853 heat-treated steel. Not every backyard mechanic with a TIG welder will know how to handle it - and rumor has it 853 is a ***** to work with.

Andrew R Stewart 

So having read this thread for a day but without time to compose a reply I now can. While the photos are not conclusive, even a first hand examine can be doubtful initially, I do see a line running through the paint and rust area. I'd be willing to call it a possible crack. But there's a way to know for sure without resorting to sand blasting of more paint removal. That's to see if any liquid can seep through or not.

here's what I would do. First strip out the BB, cranks, post and such to have unrestrained access. Then Clean the outside as well as I could with solvent. Position the frame so that the "crack' was at the lowest point of the ST. Now add a thin liquid to the ST so a puddle sits on the inside at the "crack". Wrap a piece of paper around the ST at the "crack" wait and see if any liquid stains the paper. I'd consider using a penetrating oil. If there's seepage then there's a crack.

Safe, simple, no special tools and can be done at home in the living room if needed. Best is that if there's no crack the further rust prevention step has already begun. Andy

mkemmer1

Thank you very much for all the replies – I'm going to bring it to a small frame building company in the next few days and hopefully we can figure out if there's a problem and what can be done about

mkemmer1

Well, I did exactly that this evening. There was a small hole at the bottom of the seat tube (purposeful - about 5 mm across) where it is welded to the bottom bracket tube, and holding the frame in place with a piece of filter paper from the coffee pot wrapped around the potentially cracked area I poured about a half a cup of WD-40 down the seat tube. I didn't have any other penetrating oil and I'm sure good ol' WD 40 was not ideal - but what the hell I really wanted to figure this out.

Using my finger I plugged the hole at the bottom of the seat tube and let the frame sit for about five minutes, angled towards the side of the crack with enough WD-40 to clearly fill up the tube above the level of the potential crack. After five minutes there was no seepage and the filter coffee filter paper was dry. Removing my finger the half a cup or so of WD-40 spelled out on the grass. So? Maybe no crack. I'm going to take it to a local friend builder and have him check it out because I'd like the frame repainted anyways at this point now that all the components are off it. Again, I'm sure WD-40 wasn't ideal but it was the best I had and I figured if it something was going to seep through that would do it. Thanks for the advice!!

mkemmer1

Here's a better look -

Andrew R Stewart 

Did you take the frame to your friend/builder yet? Andy.

FBinNY 

I see some etch, probably from rust, but no hint of a crack. Put some paint over the bare metal, then build it and ride it until it dies --- which may be a long time out.

habilis

If there's ever a next time, there's a much less invasive and easier way to check for structural weakness. Do what the dentist does when checking for a soft spot in a tooth: probe gently but firmly with a pick or similar tool. If the steel is rusted badly from within, it will cave. If it feels firm, forget about it and ride the bike.

sch

Well, good on ya... Rust was superficial and tubing looks good for another thirty years or so. Now prime and repaint that patch and any others.
I would suggest pulling at least the seat post and giving the inside a good exam with very bright light to see if there is any internal rust.
A google suggests you can replace the Reynolds 853 decals from several sites for nominal amounts.

mkemmer1

Thanks to all who responded! I've had this frame for 19 years and had many great memory riding it so I'm happy that it looks like il be able to keep riding it. I was not able to get it to a frame builder, though talking to some on the phone and having them look at the pictures I'm more confident it's not a crack.

I had the bike repainted after 10 years and that wasn't my original intention but I'm going to have it repainted now at the same place – they can also weld it or do something if they are a little worried about the crack if the are concerned. They do a good job of cleaning up the whole frame and I think that prolongs the life of it. Considering I was going to spend $2000 or so on a new frame probably 500 - 600 on a new paintjob should be OK. Heres the bike shortly after it was repainted 10 years ago -