It almost sounds like that may have been a defective rim, or something in its handling over the many years of storage before you had it built up caused a hairline crack, which then propagated when ridden. I would try rebuilding with the last NOS Ergal, then watch it like a hawk for any cracks.
IMHO, Ergals usually seem to die of fatigue at high life ( maybe 25-50K miles?). They are very light and made of 7000 series aluminum that is very strong (hit a pothole and they don't get flatspots), but they will eventually shatter if impacted hard enough. My Ergal failure experiences have always been ferrule blowouts about the size of a dime (not great if you have a 24- or 28-spoker; you're pretty much carrying the bike home at that point). They are right near the limit of the weight vs. durability tradeoff in my opinion, but they are oh-so-sweet until they break. By the way, they weigh about a true 280-290 grams w/ferrules, whereas a lot of other rims fudge their published weight significantly. Damon Rinard has a site where he weighed a bunch of production bike parts including many rims. His Ergals weighed in at 282 grams or thereabouts! Anyone have the address of that site (my computer that had it bookmarked lost its hard drive unfortunately).
Greg "love Ergals, but I only weigh 155" Parker in PC Ann Arbor MI
From: "Rick Verhoeven", INTERNET:email@example.com To: , INTERNET:firstname.lastname@example.org
Date: 2/11/01 12:49 AM
RE: [CR]Broken Ergal Rim
I kept meaning to bring this up during the "28 hole hub" tread that went along last month, but I missed it.
I experienced my first broken rim a couple of months ago. Having heard many raves about the ride quality, I acquired a set of 36 hole NOS Fiamme Ergal rims to use on my "new" '71 Masi. I had them built by a well known wheel builder who has much experience with vintage wheels including Ergals. After about 200 (easy but wonderful) miles, I noticed a very small crack along the top edge of the side of the rear wheel. Over the course of the next few days, I watched the wheel gradually pretzel itself. Even after I completely loosened the tension of all the spokes, the wheel continued down it's self-destructive path eventually popping a 1.5 inch piece of rim sidewall completely off the rim!
I was well aware of the liability riding the Ergals (especially at my winter weight of 185 lbs.) before I ever purchased them. I have been in touch with the builder, and he graciously offered to re-build the wheel for me if I supply the rim. I do have one more NOS Ergal, as well as, a cosmetically matching NOS Fiamme Red label. Should I even consider using the new Ergal or just be safe and use the Red?
In addition, though my weight stays in the 180's I've never had wheel problems at all including many, many hard miles on a set of Mavic GL 330's (36 hole). Also, I know that I didn't hit anything hard during the 200 miles I used the wheels. Any thoughts? Opinions?
Rick VerHoeven with drippy nose and a cold in a drippy and cold Twin Falls, Idaho.