Originally Posted by RandomTroll

The rim of my front wheel split today (I didn't hit a pothole or any other wheel-damaging obstacle: just normal street riding). Fortunately it held the tire's bead until I got home, 15 miles later. My last front rim split and stopped holding the bead in 1 fell swoop 6 years (37K miles) ago. I noticed a bulge (from the sound made while braking) 10 months ago. I squeezed it flat with vise-grips. When I started today's ride it braked normally. It's a Sun CR-18 rim.

Is there a rim-wall-thickness I should use to determine when to replace a rim? Or some other measure?

I ride to minimize braking: slowing down when approaching stops, looking ahead for problems. Is 37K too-few miles?