I've a 1994 GT Vantara, with a steel frame. I'm not 100% sure on the exact steel type however; looking up the model and year, it could either be full cromo or just have a cromo main triangle. Regardless, this didn't prevent it from forming a crack at a welding seam, at the point where the top tube and seat tube meet. The top tube is oversized and so the seat tube was fitted through it and welded it place.
My question is: do I need to worry about it? It is only a localized crack, and doesn't seem to be growing. If I do infact need to worry about it, should it be taken in to a repair shop as soon as possible, or can I finish up the riding season and send the frame in for reapairs during winter? Thanks for any help.

Here are some picture of the bicycle and the crack




PS. sorry if the pictures are huge, no idea how to resize

The crack will only grow with further use. So, if you have been looking for an excuse to get a new bike, here it is. If not, get it repaired now. My welder friend could do that in about 15 minutes with a mig. Grind the paint off, wire brush it out and Zap it. bk

It MAY just be the paint. Pick away at the paint and open up a small area so you can clearly see the metal below. If it's actually the metal that is cracked then you need to evaluate and monitor the crack to see if it continues to grow. But this does not make the frame unrideable. At least not at the moment. The crack, if it is actually into the metal, is on a part of the frame that is pretty much 100% cosmetic. I'd be inclined to drill 1/16 or 3/32 holes through the ends and in line with the lay of the crack and from there monitor to ensure that the crack does not spread from the present size. If it does then deal with the issue. If it stays politely idle then you're in no danger of a sudden frame dissassembly while riding.

Ok, thanks for the help you guys... looks like no immediate danger, but I will eventually get it fixed. I found out how the crack started. The stantard seat post that came with the bike was undersized (25.4) when it really needed a 27.4 post. The result was that the quick release seat was over tightened and caused the crack. Huh. I've switched the post, so I'll see how that works.

Hmmmm...

Good grief, that was a huge mis-match when it comes to seatposts. I'm amazed the seatpost clamp could be tightened enough to keep the undesized post from slipping without breaking off the "ears".

Drill holes at end and have it brazed rather than welded to avoid distortion which may give more problems with seat post fit

I go with the drilled holes. In the metal trades they are called policemen and help to keep the crack from growing.
It should be repairable by welding if you can find someone qualified.

Are you the origional owner, and does it have a lifetime frame guarantee?

I am the original owner, and it does have some sort of guarentee, but - 1) I'm not positive if the frame is lifetime warrenty'd, but I assume any good steel frame would be, and 2) this bike was bought pre-bancruptcy, so Gt is under new ownership, and I'm not certain they will honour past warantees. I contacted GT > 2 weeks ago about this issue, but no response as yet. Poor customer service.....