Any idea what could have happened to my rim?

[CaptainJones]

So today I got a flat tire (unrelated, it was a nail, extracted, repaired. All good) and when I pulled over to try to find what caused it, I noticed that my rim was rubbing the brakes the way it does when it's out of true because of a broken spoke.
The spoke is fine. It's the RIM that's been damaged, and that has damaged my calm some. I took it to my usual bike shop, guys are pros, figured they'd have an answer, no such luck. They gave me vague language about how it "looked like it had been hit pretty hard," and that they "see it all the time," but were unable to tell me WHY damage like that could occur, how I could prevent it from happening again, or whether it was something wrong with the rim. They even took pictures of the rim before they handed it back, one was clearly puzzled by it.
Worth noting is that I typically replace my own broken spokes, and true my own wheels; I've been doing it for decades and my proficiency is fair. I don't over-tighten my spokes, if anything my hand is gentle. But the spoke pictured is original to the wheel, so it's not like I over-torqued it with a spoke tool or anything. The spoke on the opposite end, as well as the ones on either side, are also original to the wheel.
Wheel is a Forté Terramax 26", brakes are rim brakes, rim was appx. 2 years old, many miles covered but all on street, all very cautious.
Just looking for answers here, anybody have any idea what could have caused this?

[Joe_W]

Wow. I have seen pictures of cracks forming at the spoke holes, but never seen one rip out completely. It is a weak spot in the rim. After two years (you might still have luck with the warranty? At least contact the manufacturer, you might be lucky.

As to the why, that is really hard to say. I know that some rims have limits for the spoke tension - but more importantly, for the maximum tyre pressure. Other than that: no idea. I tried to find out some specs, but no luck (only a quick google-ing, so...)

[CaptainJones]

Thanks for the response! Nice to know that others are baffled too, will do my best to contact the manufacturer. Specs can be found Here.

[DaveM]

That's a pretty bad failure. But I've seen rims fail like this quite a few times. There was likely some underlying weakness in the rim at that point. But there was probably some minor triggering shock. I've seen rims fail from hitting a good pothole, overtightening spokes, even from a tube blowing out. Hard to say exactly what "caused" the failure.

Certainly worth talking to the bike/rim manufacturer to see if they'll do anything for you. But I wouldn't assume it means anything more than 'you had a bad rim that failed'.