Originally Posted by africanomad

Telling one from the other .. is that merely a matter of price, or are there brands to avoid? It's hard to say what brands are bad as I don't have any experience with bad frames. But I wouldn't trust a department store brand bike. If longevity is your concern, go for one of the bigger brands such as Trek, Giant, Cannondale or Specialized. They're more likely to be around when it comes time to test your warranty


Flexy? Aluminum is really not supposed to flex at all. The reason aluminum frames are stiffer than steel is because it fatigues and fails if flexed many times. Steel can flex repeatedly forever without fatigue. All frame materials flex. It's true that aluminum weakens as it flexes, but if your frame is good, it will take many many cycles to get it to the point that it is unusable. Regarding your comment "Steel can flex repeatedly forever without fatigue", that isn't true.