GreasyChris
Well-Known Member
No I didn't. Everytime I find one of those bikes they always sell quick
Broken frame
- Thread starter GreasyChris
- Start date
Chainlube
Well-Known Member
I have a Schwinn 5Star that I could sell you. I haven't been trying to sell it because it's an 80s bike in prime shape. Hopefully you'll find another real close.
bike4life
Well-Known Member
"Ferrous alloys and titanium alloys[2] have a distinct limit. Other structural metals, such as aluminium and copper, do not have a distinct limit and will eventually fail even from small stress amplitudes. In these cases, the term endurance strength is used. Endurance strength is defined as the maximum value of completely reversed bending stress that a material can withstand for a finite number of cycles without a fatigue failure. "
-from wikipedia
-from wikipedia
GreasyChris
Well-Known Member
Thanks but I'm not in a huge rush. I'm still building my red bike with the minarelli engine. So I'm thinking I'll just rebuild it over the winter.
Vikingimike01
Well-Known Member
Thats really weird. And it doesn't look like the frame is weak or thin at that area... I guess saving money on quality materials?? Hmmmm....
bike4life
Well-Known Member
look at what I said from wikipedia above....
Aluminum has no fatigue limit / endurance limit
if you put a 1 gram load on it and cycled it 1,0000000000000000 times it would fail... I am probably exaggerating a little bit here but you get the point.
Steel has a fatigue limit where if you put a certain specific load that you calculated in the formula, it would not fail.....
See that endurance limit, if you put a 30,000psi load on it for infinity cycles it would never fail, as it has a limit.... See how the blue line, it flat lines and never gets lower. You can do that till the universe dies and it wont break. lim x ---> infinity = 30kg in this chart
Aluminum steadily declines after each cycle... Each cycle it handles less and less until it approaches 0. Mind you that would occur on 10^9 cycles, but still. With aluminum, if you put a gram on it and cycled it for 1 billion years, it would probably break, as it eventually approaches 0, that red line... Hyperbole here but you get the point. lim x---> infinty = 0
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Vikingimike01
Well-Known Member
Ok we got it you don't like aluminium frames!! Don't need to post 5 times about it in one page....
Street Ryderz
Well-Known Member
Sorry to hear this brother!
Street Ryderz
Well-Known Member
I don't think you understand what the endurance limit testing entail's! Reverse bending is how that's done and not just putting weight on it,when aluminum frames are made properly the wall thickness of the tubes is generally twice as thick compared to steel and still remains lighter.Weak points like the dropout above need to be thicker and gusseted then will last forever! I've never seen a Felt or even a faker frame fail at that point because if you look at the geometry and thickness there they did it right,guy's with very heavy 4 strokes use that frame with 200+ lb riders.
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