I'm scared ;_; does frame/component failure really happen?
Should I ditch my 20yo bike?
>>965379
>does frame/component failure really happen?
yes
will it happen to you? probably not.
>>965379
aluminum has a limit. eventually, all aluminum bikes will break. probably not in your lifetime
steel and carbon theoretically have no fatigue life. you can flex them over and over, and so long as it is within a certain range of safety, it will never break. you could set up a machine to lightly flex one for centuries and it shouldn't break.
aluminum, eventually it will snap
I ride aluminum frames anyways, so you can see how much I care about this fact
>>965409
>steel and carbon theoretically have no fatigue life. you can flex them over and over, and so long as it is within a certain range of safety, it will never break. you could set up a machine to lightly flex one for centuries and it shouldn't break.
Maybe if you're putting out 50 watts on glass smooth pavement.
http://www.sheldonbrown.com/rinard/frame_fatigue_test.htm
>>965434
>http://www.sheldonbrown.com/rinard/frame_fatigue_test.htm
mind blown
I need to stop believing shit I read on bikeforums
>carbon theoretically have no fatigue life
>it will never break.
>you could set up a machine to lightly flex one for centuries and it shouldn't break.
Maybe
Too bad the reality is full of failed garbon
1990's chromoly rigid mtb master race reporting in
>>965441
>http://www.sheldonbrown.com/rinard/frame_fatigue_test.htm
CANNONDALE
A
NN
O
N
DALE
>>965379
Yes, but most often it's due to severe neglect or abuse. E.g. letting bike sit outside during winter - water gets in frame, freezes and cracks it. Or using what obviously is a city/touring bike do big jumps and land on a hump with each wheel on opposite side of said hill.
>>965478
The problem isn't the carbon itself, it's the binder. Also, the modulus of flex and the young's modulus are much closer for carbon than it is for most metals.
>Daily rider: steel.
>Race: alloy or carbon.
If you're not racing don't play pretend, you will be much happier.
>>967090
>Also, the modulus of flex and the young's modulus are much closer for carbon than it is for most metals.
What are you smoking?
>>965434
>>965441
Yep. There's so much hobby science in the bike world, it's so stupid.
"Hurr durr, steel has a fatigue limit below which you can cycle it indefinitely without failure, but aluminum has no fatigue limit and will always eventually fail due to fatigue, therefor, steel is way more durable" and no one ever questions what those fatigue curves look like for various materials, or whether a lightweight steel frame is *actually* loaded below the fatigue limit or not...
(Hint: All but the most overbuilt gaspipe steel frames are DEFINITELY loaded above the fatigue limit...)
Carbon's only real problem is impact resistance and the fact that it generally fails catastrophically. A well made carbon frame that isn't smashed into stuff should outlive the usefulness of all the components it came with.
On the other hand, a good steel frame should last a hell of a long time as well - and when it does crack, it's generally fairly easy to repair. Aluminum is trickier because you really need to heat treat the welds after repair to get back to the correct temper.
if youre a 120 lb woman riding on well paved streets youre not going to fatigue/overload a bike frame ever, if youre 220 lb and ride rough ground you are only going to last on steel
>>965379
Happened to me once on the front bit of the downtube (old steel kid/city bike).
I still managed to get home (a couple of km) and drive a few km to the mechanic the next day without a problem.
