Rix
100 TW
litespeed said:Rix said:Mammalian04 said:Well that's scary... It makes me want to think twice about the hard landings.
This is an excellent example of the great characteristics of cromo steel, when the steel lets go, it does so slowly and not all at once. This is one reason why Stealth uses cromolly steel sheets for their frames. Don't be alarmed guys. this kind of failure warns the rider. Gives plenty of time to correct.
Rix,
Sorry i respectfully disagree but cromoly steel usually breaks not slowly crack. I think your confused with mild steel. That is why most roll cages/tube frames use mild steel because they bend and don't break. Crome is harder, stronger so it can be used as lighter material but not ideal for all cases. Does really bad in high vibration areas, ask me how I know. Well at least mild steel does good until it work hardens and then anything can happen.
In my opinion I think the frames are OK for crome but think the seat mount should be mild steel sized accordingly and would
never have this issue.
Tom
Hey Tom, you are correct about mild steel and I agree with you. It bends and bends because its not brittle and generally doesn't have very much carbon content in it. I have confirmed with Stealth that the triangle seat sub frame made for their bikes is out of cromolly, sheet plate. I don't know what the chromo content % is though. The way the frame is cooled after welding allows it to not be brittle like it would be with a quick oil quench or with water. Anyway, my point was, I have seen multiple sub frame failures and none of them were quick, snap in half type failures. The were slow cracks that gradually grew longer and wider with continued use. Now don't get me wrong, if allowed to go on long enough, the frame will fatigue and break off completely.