Cracked rim - adequate for trainer use? I'd just bought a used wheel, but didn't actually notice its quite serious crack on the sidewall of the rim (silly me, quite foolish to not inspect it).



In this case, what are the odds of it failing, when used exclusively on a trainer?
If it where a tiny crack and your trainer was the type that holds the weight by the skewer then maybe, but the damage shown may be too risky even to mount and inflate the tire onto it.

I think the outward pressure from the tire might further break the rim walls and expand them, causing contact with the bike. If that happens while your'e spinning the tire it may cause serious damage to the frame. It could also send debris in any direction that may damage your floor, furniture or cause injury to you or someone nearby.

EDIT: Indeed the damage is in the area of the seam, but there are also two hit marks, on each side of the rim, on each side of the seam, and there is also what looks like a longitudinal crack (between the painted section and the brake track). To me it seems this rim was bashed hardly right on the seam.

I think you better throw it away or make a lamp or other decorative object out of it...

Inspect the hub to see if it's worth keeping as a spare. Maybe the spokes too.