Bicycle Mechanics - Rim damaged in curb scrape, keep using or replace?

A rider in my Tuesday evening group impacted a curb with a glancing blow, fell down (with no injury), but discovered his rim had been gouged out in the area in the rim brake contact zone, as though a chip about an inch long and maybe a 1 mm deep had been scraped out.

I thought it to be a significant stress riser in the rim and would lead to a speedy cracking failure, and told the guy he should replace it after that ride, which had another 7 miles to go. I also suggested he slow down in case the rim did crack he wouldn't go over the handlebars - as hard. He made it back following the A pack going pretty fast, as much as 25 mph in a few places, and thinks probably it will be ok and he can continue riding.

Am I right - he's risking his life, or is he right - he can keep running with little chance of a disaster?

It's a 26" mtb rim x about 27mm wide, aluminum, probably the same 25 years old the bike is. Is being super cheap with equipment expenditures a good excuse to take risks like that, or am I just paranoid? :eek:

If it were me, I'd replace it. But maybe your description is a bit alarmist? Anyway, a wheel that old, it seems like just ignoring it would be imprudent.

Without seeing a photo, and knowing exactly where the scratch is and how deep it's impossible to render a meaningful opinion, but I think you may be a bit alarmist in your assessment. Rims have been known to last for years after stones caught in brake shoes carved out long and deep concentric gouges.

One consideration would be whether it was in the unsupported tire flange, or within the box section area. Other factors include the thickness, and alloy involved. Interestingly low end rims are probably more forgiving than top quality ones. I'd also be more likely to continue using a damaged rim on the rear wheel than on the front.