Originally Posted by
Trakhak
About the rates of failure of different frame materials back then: there's a fascinating ongoing C&V thread where people are reporting their experience with frame failures. So far, the reports seem to be running about 5 or more failed steel frames to each aluminum frame---and the aluminum failures reported include Alan- and Vitus-built small-diameter-tube frames, known for being somewhat failure-prone.
Anecdotal, obviously, but I suspect that the ratio will continue to be roughly the same as the stories continue to roll in. I worked in a couple of the biggest bike stores in the area in the '80's and '90's, and that's about the proportion of damaged frames that I remember.
Cannondale's engineers were working to refine their designs throughout that period: hence the successive CAD---and, later, CAAD---series numbers, prominently labeled on each bike. They'd figured out early on that riding comfort did not decrease with increased structural rigidity and/but that the increased torsional and lateral rigidity did result in improved handling and wheel tracking. And the bikes kept getting lighter!
This is opposite of what was stated in one of the Cannondale articles. The increase in structural rigidity was necessary to increase durability and the tradeoff in riding comfort was a compromise that had to be made.
A survey of bikeforums in 2023 about frame failures 30 years prior isn't a very robust data set. For one point, most of the riders who were riding contemporaneously are not posting here. The other is that, there are less than 50 unique responses in that thread. I've broken 3 aluminum frames and 1 steel frame and didn't reply. We also don't know the population of what was/is in the market. If there are 5 times as many steel frames in the market as aluminum, than the ratio makes sense. But there's no robust data, it would be trivial to produce an estimate showing one or the other with a higher propensity to fail. What we can glen from contemporary articles is that aluminum was considered by many including manufacturers themselves, to be less durable than steel.
I worked at both REI and Performance Bicycle for the better part of a decade in the 2000s-2010s and the only steel frame failures I saw were very old lugged bikes and newer bikes damaged in curb impacts. We would warranty at least 2 newer aluminum frames a month, usually cracks in the bottom bracket/downtube/headtube HAZ or the dimples in chainstay. Of course, we also sold almost exclusively aluminum and carbon fiber bikes. It was rare to see an aluminum bike from the 80s or 90s, especially that had been ridden a lot. Whether this was due to market forces or an indicator of durability is unknown. Steel bikes from that time were very common.
Originally Posted by
Trakhak
One of the articles SpeedOfLite posted was the earliest I've seen where the writer said that a Cannondale racing bike had a particularly hard ride. He blamed the frame but then swapped the tires (23 mm to 25, I think) and said the ride was much improved. Somehow he didn't draw the all-but-obvious conclusion. (The bike under review was a Crit Series, too. See my previous post on that topic.)
There's another little time capsule here: the era when bike tire manufacturers lived and died according to what riders saw in bike magazines. Riders would look at ads, see that, e.g., a Specialized 23-mm tire weighed 50 grams less than another brand's tire of the same dimensions, and buy the Specialized tire. Unbeknownst to that rider, Specialized's tire was 2 or 3 mm narrower than the labeled size.
There's a good chance, in other words, that that Cannondale's 23-mm tires, so-called, were actually 21 mm, 20 mm, or even 19 mm in width.
The bike magazines eventually caught on and began including both the weight and the measured inflated width of tires in their reviews. (I could be wrong, but I seem to remember that Continental was one of the few companies that had labeled their tires accurately all along.)
These editors were riding the same tires on steel bikes and recording their observations as well. So if an aluminum bike felt harsh with 19mm tires but good with 25mm tires that framework applied to steel produces the result already mentioned. Steel at 19mm is more "comfortable" than aluminum at 19mm and continues with both at 25mm. Which is what the outcome most of the editorials reached.