They all crack if you crack them. Some materials crack better than others. Walmart aluminum is probably the best crack for the buck.

It all depends, however, it's important that you don't get involved with crack.

I personally dig the spring.

My Stumpjumper hardtail is an AL frame & its nearly 10 years old, still looks like it almost new.
I'm was pretty hard on her, but I made sure to maintain her too.(retired)
My Opus is also AL, I hop curbs, & take jumps on concrete @ 15-25 KMs.
There's this one route I take when I go hard on climbing, & sprinting.
@ one point there's a small bridge where the drop is about 2.5-3", I just jump it cause I don't want to slow down so much to"roll" down it.
Is this good for my bike? Probably not but she takes a kicking, & keeps on ticking.
Is my bike meant to do this? Probably not, but its a Cyclocross so it should she able to take these bumps, & jump
Speed 20-25 KMs/ my weight fluctuates between 145-155 lbs/ 2.5-3" drop = ???
Glad my tires can handle the abuse.

Did you ride you BMX when it was all rusty? I know I did as a kid.
Did it even fail on me? Nope.

Yes.

Although your assumption may be correct, the comment is valid. The assumption is not.

I've cracked a few aluminum road frames - an older Cannondale, a Specialized M2, and a Giant TCR.

There's the concept of pushing the limits with materials. If you build something so that there are no failures then you've overbuilt it. At the same time you want to have no failures in certain parts, so, for example, I'd consider a fork, bars, stem, and steerer to be the "no failure" parts of a frame/fork.

All my frames failed in the chainstay, about the safest place for a frame to fail. None broke through. I rode all of them for a while before replacing them (a month or two). Other than some creaking, some tire rub under pressure, the frames were rideable (and raceable). In all three instances I didn't know the frame was cracked until I happened to find the crack (or a coworker did).

I've also seen some amazing steel frame failures, the most incredible a Pinarello whose top tube cracked in half. The ride noticed something wrong in the last lap of a race when his bike felt "bouncy". It should have - you could push the saddle down a good 2-3", until the bowing bike's cranks almost hit the ground.

I broke a ti axle BB (the right arm came off, reminiscent of Fignon's Campy SR ti axle failure). All materials have their limits and design limitations.

I happen to ride aluminum frames. I'd ride carbon (have in the past) but custom carbon is too expensive. Fit > Material.

They make bombs with aluminum. Also with CF. Aluminum AND CF therefore explode. Stay away from Aluminum. And don't spend much time above ground - those Al airplanes that fall apart in midair might land on yer head.

Wonder where this thread will go....:popcorn

We have to put the aluminium bike frames in travel cases and put them in the hold of an aluminium airplane to travel to the Century ride in Vermont. Yikes! Aluminium failure squared....:p

The most shocking part of this story is the number of Texans (tattooed and otherwise) using the term "aluminium".

Its because we watch Top Gear :lol:

Yes, Aluminum has a theoretical fatigue life, but you are very unlikely to reach it. I don't think it should even factor into the decision unless you are seriously looking for a bike you can ride 20+ years. How long do you plan on keeping the bike anyway? I find it funny that people talk about how steel or TI or CF lasts longer and how AL has a fatigue life limit, but then get a new bike every 2 yrs.

The key is to ride different bikes and pick the one that you can afford and rides how you like it. AL has a reputation for being "harsh", but honestly that depends on the bike, not the frame material.

I'm weary of tattooed crack head poseur sale pushers, I'm weary of the LBS owner who could give a $&@t about his/her staff. The two together are a disaster for the buyer.

How right you are svtmike...you are looking at one of the worlds worst spellers...something to do with my dyslexia I think...If you be my bodyguard you can call me Al

God talking to bicycle frame materials...

God to Steel

God: Steel, you are very blessed my child. For you have remained a faithful servant unto your master throughout all these years. It is due to your many years of relentless dedicated service, that I am granting you everlasting life
in paradise.

God To Carbon

God: Carbon, of the short time you've been here, you've shown signs that you may be quite capable of serving your master with the utmost of faith and dedication. Of course, there have been times when you have wavered, due to your useless sensitivities and your frivolous whimsical emotions. As your master, I will not have a fickled servant. You must learn to remain steadfast in your service. Therefore, I am forced to temporarily banish you! It's to purgatory you shall go!

God To Aluminum

God: Aluminum, you have done nothing, but stiff many innocent people all the days of your short life. You have been harsh to all those in need of comfort. When expected to uphold and abide by the demands of your master, you have failed, catastrophically.

....Aluminum! Your days are numbered!

Something that gets lost in the hysteria surrounding frame failures is that it ALL fails by cracking. Any failure from fatigue always manifests as a crack, whether the material is aluminum, steel or titanium.

"Catastrophic failure" is a classic shibboleth of aluminum. The reality is that failure from fatigue (which is the source of the vast majority of frame failures, not impacts) looks exactly the same in both aluminum and steel and is not immediate in either one. Once a stress riser develops in an aluminum frame, it WILL propagate faster than it will in steel, because the material is not as tough, but you don't typically go from zero to broken frame immediately even with aluminum. In any case, most frame failures happen either on a chainstay near the bottom bracket, or the bottom of the seattube, again very near the bottom bracket, and these usually go unnoticed until they reach the point where they fail completely. Whether you're riding steel or aluminum, this might as well be a catastrophic failure, if you don't notice until the tube actually breaks. But that doesn't particularly matter, because this kind of failure isn't particularly dangerous. The tube cracks and the frame suddenly goes all noodly, but it will hold its shape and not fall apart. A dangerous failure would be at the headtube or downtube, but these are comparatively very rare and usually caused by crashes, not fatigue. The fatigue failure to worry about would be the fork. But fortunately, these are rare as well.

If you're worried about catastrophic failure, I wouldn't be concerned about a frame, I would be concerned about handlebars and such (though, again, the failure probably isn't catastrophic so much as it a gradual failure from fatigue or corrosion that goes unnoticed until the part suddenly breaks). Most of us are riding aluminum bars, stems and seatposts, though, whether we are on steel, aluminum, Ti or carbon frames, and few people make much of this. I just don't think that there's much to be made out of how a given material is believed to break. Even if aluminum frames break more often, I don't think that necessarily makes them more dangerous.

OK, just so you know Jim grew up in the great state of California! We Texans take offense to slights against our spelling. Oh wait I did ask that misspelling Californian to marry me. I ride aluminum and recycle it too.
Kitt
Jim's wife of 27 years LOL

Yep, as I mentioned, this is where almost all fatigue failures occur, no matter what the material. And when it happens, the frame is usually at the very least safe enough to coast to a stop, often still rideable.

I have had a steel fork crack right below the crown lug, by the way. Scary stuff. I was okay because I had a front rack on the touring bike I was riding at the time, that was the only thing holding it together. I knew something was up when I noticed a lot of vibration while braking. Everything and anything can break. All of it.

Tell that to the people that had lugs pull apart or welds break

After a lot of stress, all frames can have problems. Aluminum does crack more frequently than carbon. Alu is actually safer because in the event of a crack, you'll notice it where on a carbon frame you will have a hell of a time looking for a crack.

Broken welds or lugs that pull apart are pretty much always consequences of manufacturing defects, which is a different subject from simple fatigue failures.

I forgot about the steel fork that came with my first aluminum frame. I was having some headset knocking, couldn't adjust it out, and figured I should let my teammates who worked at the shop look at it (I was 16? at the time). Of course I had a race the next morning so time was tight. One older teammate (and shop guru) said he would reface the frame - he suspected the cups weren't parallel. He started working on the bike by removing the front brake - and the fork blades fell onto the floor.

The steerer tube was not connected to the fork crown!

The only thing keeping the fork on the bike was the front brake bolt. Apparently the fork wasn't brazed properly (duh) and the (steel) crown separated from the (steel) fork legs. Of course I still had this race the next morning. The teammate happened to be a metal guy as well so he took the frame that evening and brazed the fork crown to the steerer. In order to make things look "less suspicious" (this was back in the day when they inspected bikes before a race), he spray painted the crown and the top of the legs in the morning (a similar red to the original color). I wrapped the seam with some tape that matched my kit to hide the seam and to try and distract any inspectors from noticing the mismatched paint. The paint was still sticky when I went for inspection but no one said anything. I raced that frame/fork for maybe another two years. I wrecked the frame but I believe the fork is still in service.

Here's my 1990 Trek 1400. ;)

http://farm8.staticflickr.com/7206/6...f1fab4f2_z.jpg

I know. I'm just giving youa hard time because you said "frame failures is that it ALL fails by cracking"

I have an aluminum CAAD10, and wouldn't trade it for the more expensive low end carbon frames.

Of people I know...I have seen cracked steel, cracked aluminum, and cracked titanium...and none of them were even in wrecks! The only frame that has not been destroyed by someone I actually know is carbon...and that's only because they treat carbon bikes like Faberge eggs. lol

Basically, any bike material will break. But it doesn't happen very often. So don't worry. Ride your bike! :)

carbon is just for show off
aliminium is for men

Don't have a carbon frame, eh?

This is not true.

That may be true as far as it goes, but it's unreasonable to limit the discussion to only failure by fatigue. On two occasions I have suffered non-fatigue related frame failure while riding steel bicycles. In both cases I was able to continue the ride/race. On aluminum, that would not have been true, and my injuries would have almost certainly been much more severe.



I don't think there's any way you could actually know that to be true.