This is the valve hole on a Hed rear wheel bought second-hand five years ago. I don’t remember this crack when I changed the tire then, or hitting any major potholes in races (the only time I ride this wheel). The scratches were there when I got it, not sure how they were inflicted either.
Apart from the puzzle of how it formed, is it a problem to ride this ? I’m going to I think, but dissuade me if it looks dangerous…
just not a happy looking rim in general.
rear or front wheel?
has your dog been chewing on that thing??
wtf is up with all of the gouges?
maybe teh crackwasn’t there in the past but that ding/gouge that it formed on might have been
Yow. That thing looks like somebody took a hammer to it. Looks like you hit something squarely with the valve that caused it to go out of verticle in a violent manner (looking at the opposite bend pattern in the metal)
Is that pitting corrosion around the edges? I’m not sure if that wheel is done for or not, but I’m not sure how many mountain passes I’d trust it on anymore. Is it a matching set? Might make a nice CX wheelset from now on.
Is it a matching set?
the only gear I have that matches is pairs of shoes 
the front is a zipp 440 which still seems OK. I don’t want to get another rear tubular and equally don’t feel like blowing a thousand or so on a clincher race wheel set…
hard to tell how safe it is from the pic, it looks like its been ridden flat a few times, judging my the basetape imprints in the edges. its possible the valve was moving around during a flat causing the denting, which caused the crack.
Its a tubular rim. I’d mount up a tire and ride the hell out of it…maybe check it again at the end of the season. My bet is that you won’t see anything worse.
If that were a clincher, I’d be looking for a new wheel. Totally different forces at work.
And someone should stop using screwdrivers or hex wrenches to pry the tires off.
bump for Monday…
Not really a mystery on why the crack developed: A scratch at the edge of the hole caused a stress concentration point and the crack developed from there.
I think you’re safe to ride that rim for maybe another season, just be sure to inspect the development of the crack after each use. And please use more glue when mounting your tires.
Maybe you were riding along and someone shot through your tire and rim with a .22!
I’m sticking with that.