Bought a steel vintage trek from the early 80s and was installing a new bottle cage and noticed this line around the bottle cage, is this a crack in the down tube? Is this frame done? It was tightened to less than 3nm so was more than likely pre existing when I bought it.
by Pilkmentallodos
8 Comments
That is a crack but it’s a Steele frame. Get it welded for brazed by a frame builder not ideal but very repairable.
Edit you cannot do that damage with the bottle cage bolt as it’s most likely a rivet nut and not a part of the frame.
It’s a steel frame. It very well might be just the paint cracking as it is exposed around the rivnut.
I wouldn’t much weight on that nut, but you should be fine. You could get it fixed from a frame builder, but it might be more than the bike is worth. I’m assuming you aren’t bombing huge downhills or putting out 2000Watts?
Just chiming in to clarify some confusion, ain’t no rivnuts on an early 80s Trek, that’ll be brazed in. Most of that crazing is just in the paint, but that darker line is more suspect. Considering where it is, I think if you can verify it is a crack, you could still stabilize it by drilling out the end and have some [fancy reinforcement](https://ebay.us/m/ZyuruL) brazed on.
That’s not a rivnut, it’s a brazed in bottle boss. The crack actually goes out to that faint dark spot next to the reflection line (not the rusty paint chip lower in the pic). It’s a bit hard for me to believe that there isn’t a matching crack on the other side. But even if there isn’t, this crack is going to quickly grow. When the downtube gets too weak, the whole bike will break in half. The consequences could be dire.
I wonder if the cage was previously used to hold something heavy, like an ebike battery. It’s somewhat unusual to have paint cracks like that.
It’s something to watch. Not catastrophic. Finish installing the cage and go for a ride.
I would ride it and take weekly pics and compare it monthly, if it grows I would either repair it or ditch it.
It’s not a rivnut. If this is a steel frame and you don’t see any bend along the length of the tube, then it is not cracked. Probably rust under a paint crack. Remove the paint around that spot and check it. Clean and touch up the paint.