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Aluminum has a better fatigue life than steel and Ti? Read..(24 posts)

Aluminum has a better fatigue life than steel and Ti? Read..Jimbob
Apr 13, 2001 6:42 AM
Check this out. Very interesting. I always thought steel and Ti would be more durable than an aluminum bike. Of course, we have to remember, not all aluminum, steel, carbon, and ti frames will perform like the ones in the test. But very interesting nonetheless.

http://www.damonrinard.com/EFBe/frame_fatigue_test.htm
Design has a lot to do with it...TJeanloz
Apr 13, 2001 6:53 AM
Design of tubesets has a lot to do with fatigue life; but keep in mind, that test was done ~1996, and a lot of the failures, like the Merlin, have had the problems addressed in the 5 years since then.
Al. long lifeSLM
Apr 13, 2001 7:07 AM
There are those among us (you know who you are) that will never accept the "lowly" aluminum as an excellent frame material. Long live aluminum! (Figuratively and literally)
Al. short lifeET
Apr 13, 2001 7:29 AM
There are those among us (you know who you are) who are too easily swayed by one research result. This isn't a mathematical theorem proved to be true beyond a shadow of doubt, just an empirical study--valuable, but with its usual limitations. It is interesting that Trek OCLV (did they test just one?) also performed well and did not break. Perhaps their test, despite claims to the contrary, did not mimic enough real riding conditions. Anyway, this test covered breakage and fatigue, not rider comfort. Even if aluminum is more resistant to fatigue, there are those among us (we know who we are :-)) who would say it's at the price of being more beat up on a ride.
Touche!SLM
Apr 13, 2001 7:34 AM
No wonder why I have an all-carbon monocoque!
Come on ET, we've been thru this, even the RAAM riders cant tellJimbob
Apr 13, 2001 7:47 AM
a difference.
but Doug Sloan can :-)ET
Apr 13, 2001 8:07 AM
And what works for the pros may not be what's ideal for us. They may have built up their bodies to the point where they can barely feel it, and so the performance, especially for them, far outweighs the comfort. Not so for many of us. And this isn't the same debate as saying just lose a few more pounds. We may never get there.

Sure, the RAAM riders said they can't feel the difference. One more test. But numerous down-to-earth riders with whom some of us can identify more closely say they can. I just don't see why I have to accept the argument that even quality aluminum must equal other materials in comfort. After all, they're different materials. Of course, to logically refute your claim I'd have to do long test rides on (i.e. buy) numerous aluminum models, and it ain't gonna happen.
Not only that......Lazy
Apr 13, 2001 8:14 AM
But try riding 1000 miles in two or so days and see how much you feel. I think those guys could be hit in the head with a skillet and think "huh, I wonder when it started raining".
fine tuning the observationsDog
Apr 16, 2001 7:38 AM
There is a difference between a difference being noticeable, and a difference being important or significant, or relative more significant than another factor.

For example, I've stated consistently that tires and pressures make more of a difference than frame material. Based upon my experience and from what I've read of others, I still believe that. Sheldon Brown seems to agreee: http://www.sheldonbrown.com/frame-materials.html

Right now, I have three road bikes that are fairly different, a 1980 Columbus steel Bianchi, a 2000 Bianchi EV2, and a 2001 Colnago C40. Even among those bikes, to me tires and pressures make more difference than the frames in ride quality.

These are the clincher tires I've used in the past 3 years: Michelin Axial Pros, 20 and 23mm; Michelin Axial Pro Lights, 23mm; Continental Supersonics, 20 and 23mm; Vittoria Ultra Speeds, 23mm; Michelin Axial Selects, 23mm; Vittoria Open Corsas, 23mm. Additionally, I've used the following tubulars: Continental Sprinter 250's; Continental 225's; Vittoria Corsa's. That spread of tires can make a huge difference in feel.

Over all, the smoothest riding tires to me are the Axial Pro Lights, 23mm, at 120 psi. Higher pressure tires do ride worse to me, getting sort of jittery over even small bumps, and making steering very quick, almost too quick. The extremes are the Continental 225's at 180 psi. Pressure makes a huge difference, particularly on rougher roads.

I recently changed from Axial Pro Lights to Vittoria Open Corsas as my primarly training and long distance tire, as I was getting too many cuts in the AP's. I run the Vittorias at the recommended 130 psi, vs. 120 for the AP's. The tire is quite a bit stiffer to me, I'd say affecting the feel of the bike more than the frame.

Now to frames. I don't pretend to be qualified to generalize about the riding qualities of the various frame materials, as I've seriously ridden maybe a dozen road bikes in my life, of three frame materials. As I've noted recently, the primary difference I can discern between my three aluminum Bianchis and the C40 is less buzz; the carbon seems to dampen road vibration. This appears to be consistent with what one would expect and what I've read elsewhere. I can tell the difference on rough roads, using the exact same components, tires, and pressures. Keep in mind that this is on rough roads only; on smooth roads, I can't tell the difference among any bikes.

Yes, the difference to me is significant (significance in the scientific or mathematical sense - 'meaningful', not necessarily a 'large' difference); however, that difference is still less than tires. These are very subjective, esoteric differences, too.

I don't think it is true that RAAM riders, in general, say they cannot feel the difference. In fact, from what I've read, many of them use Softride beam bikes. Nonetheless, they place the most importance on the points of contact and positioning: http://www.ultracycling.com/equipment/setup.html , according to the Ultra Marathon Cycling Association website. They also have a section discussing beam bikes: http://www.ultracycling.com/equipment/beambikes.html .

I think it would be fair to generalize that the differences between any two rigid road bikes are not anywhere near as significant as the difference between a rigid road bike and a suspended bike. A rigid road bike can't signficantly absorb a big hit; I think we are talking only about dampening vibrations.

I've not ridden a titanium road bike, only a Ti mountain bike (Airborne Lucky Strike). While I really liked the ride of the Ti mtb, there are far too many variables with mountain bikes to tell if the frame is the difference, variables such as shocks, the shock pressure settings, oil temperature in the dampers, tires and pressures, etc. Nonetheless, Ti is reputed to dampen better than aluminum. But, I doubt anyone will be able to quantify this, as especially with mountain bikes the geometries
message cut off...Dog
Apr 16, 2001 7:42 AM
...geometries and components are so varied, it might be impossible to have a meaningful, objective comparison. I will say one thing, though, the Airborne, as I had it built, was extremely light (20.8 pounds). That alone made it a joy to ride.

So, to conclude, I do believe that many people can tell the difference between bike frame materials, but those differences will still be smaller than many other factors affecting the feel of the bike.

Doug
Me toopmf
Apr 13, 2001 8:14 AM
I've got two carbon bikes and one ti bike. I can definitely tell the difference between the ti bike and the carbon bikes. The distinction is much less between the two carbon bikes though.

Perhaps its just a personal thing that varies from person to person.

Still, all these folks raving about aluminium bikes always makes me wonder -- what are they comparing them too? What else are they riding? I suppose its come a long way since I bought that Cannondale 3.0 years ago. But that bike soured me towards aluminium ever since.
Loved Al.SLM
Apr 13, 2001 9:41 AM
I must say that before my carbon bike I rode an all aluminum (Al frame & Al fork) bike. I loved it (even with 700-20c tires at 120 psi).
If I my wife and kids didn't have to eat or wear clothes I would buy another Al bike, maybe with that new Columbus Al, I think it's called "Starship".
Aluminum is also a common choice for prosLuca
Apr 13, 2001 7:39 AM
Beyond its strength and stiffness.
Yeah, rightpmf
Apr 13, 2001 8:16 AM
Like the pros have much of a choice. They ride what they're paid to ride. You have a choice, they don't.
Yeah, right. Pros ride custom and usuallyBeavis
Apr 13, 2001 9:03 AM
have a few materials to choose from. With the exception of USPS of course.
umm guys, about "yeah, right"ET
Apr 13, 2001 9:13 AM
How can we tell whether "yeah, right" means

(1) "I agree with you wholeheartedly", or

(2) "My foot!"?

With some expressions, I sometimes have to re-read posts several times and I'm still not sure of the intent. Can one safely assume that the use of "yeah" always implies (2)?
re: Aluminum has a better fatigue life than steel and Ti? Read..PsyDoc
Apr 13, 2001 7:20 AM
I have seen this site before. I do know that Merlin moved it's shifter bosses to the headtube for precisely this reason. I may have read over this info, but were all the frames tested new?

According to the folks at the United Bicycle Institute, aluminum frames fatigue more than other materials, such as steel. Ti frames can last 20 years or more whereas Aluminum frames, as a whole, do have a shorter lifespan. How much shorter I do not know. But, the life of any frame depends on how many hours it is ridden and how it is ridden. Also, do not forget that the fatigue life of a bike is determined, in part, on the quality of the welds/adhesion. Which brings me to a related, but off-topic question. If you are riding your bike and the frame or other component breaks causing you to crash, then how do you show that the crash did not cause the damage? I started thinking about this when a doctor I know told me that many people believe that the fall an elderly person has is responsible for a hip breaking. However, he said that in many instances, the person may simply be walking and the hip breaks thereby causing the fall.

If Aluminum frames have a better fatigue life, why aren't they warrantied for life by many companies? Does anyone know? For example, Giant's warranty states: "Different materials have unique properties and perform differently in certain applications. While these differences can result in performance advantages, they can also affect the period of useful life of a product. In recognition of this fact, GIANT USA changed its limited warranty from Lifetime to Five Years on aluminum bicycles and framesets. As a material, aluminum has the advantage of being lighter and stiffer, but it will not perform as long as steel; it is more likely to fail sooner and more often from fatigue under repeated loading. In fact, after several years, particularly when ridden under aggressive conditions, cracks may develop and the frame may fail. Changing the length of the limited warranty on aluminum bicycles and frames is one way of communicating this to the purchaser."
re: Aluminum has a better fatigue life than steel and Ti? Read..Mel Erickson
Apr 13, 2001 7:38 AM
This test tells us nothing about the realtive fatigue life of the various materials. What it does tell us is that construction plays a very important role in determining durability. It's not the material but the way the material was put together that made the difference.
Aluminium will fatigue, Steel and Ti may or may not...Bruno S
Apr 13, 2001 10:00 AM
Aluminium will fail because of fatige when exposed to load and unload cycles. It doesn't matter how small the load, with enough cycles, aluminium will fail.

Steel and Ti will not experience fatigue if the load is below a certain level. Above that level they will behave like aluminium and eventually fatigue.

It is the frame design that determines its life. If the steel or Ti frames have been designed to never exceed loads that will fatigue them they could last forever but I believe this is not always the case.
Who among has had a frame fail due to fatigue?Gadfly
Apr 13, 2001 10:06 AM
I've failed many times due to fatigue, but I've yet to wear out a frame, no matter what material.
C'mon, kids, knock it off...Behave yourselves.boy nigel
Apr 13, 2001 10:15 AM
"Aluminum sucks, Ti rules, steel's next, and carbon's plastic."

We've all heard these to death on the board. To each his own or to each his reach. I can't afford high-end steel or ti (or carbon, for that matter), so I (like many of you out there) ride--and am VERY comfortable with--aluminum.

I've experienced a whole new riding sensation since I've switched from old steel to new aluminum; stands to reason. It's the best thing I'VE ridden so far. I don't know people with titanium bikes that I could test out. Even if I did, and found it to be so superior, I still couldn't afford a ti frame.

Let's just take the original post as a legitimate study of some sort. Not the be all and end all, doesn't make ti or steel or carbon out to be LESS of a frame material; just simple testing procedures. I'm not saying aluminum rules, since such a statement is ludicrous. I love my alu bike, and that's where it ends.

Enough silly quibbling and putting others' frame materials down, eh?
re: Aluminum has a better fatigue life than steel and Ti? Read..LC
Apr 13, 2001 11:03 AM
You can't argue with actual testing, and every steel frame came out at the bottom of the test. There is no question steel can't take a strong heavy rider. Every bike frame that I broke from fatige was steel. When I ride my steel bike I stay on the flats and ride like grandma around the park. The only reason pro's can ride steel is that they get a new bike every year. If you weigh over 150 and like to hammer up the hills then stay away from steel like the plague.
There's alot to it...DrD
Apr 13, 2001 12:59 PM
In terms of the materials, the Ti based alloys (and steels) used for bicycle frames have a superior fatigue life to aluminum alloys, all other things being equal - in other words, in terms of basic material properties.

However - frame design is key, here - that alone will dictate the local stresses which the frame material will be subjected to - tubing thickness, joint design, etc. - there are alot of factors (the material dictates how much stress it can take). So if you have a high fatigue strength material, but a poor joint design or a bad weld which results in a stress concentrator, you will have a very high local stress, and potentially be faced with fatigue failure of the frame...
re: Aluminum has a better fatigue life than steel and Ti? Read..Andrew
Apr 14, 2001 1:16 PM
I just read every reply to this thread and I must say that I could care less about the fatigue life of a frame. If I want to purchase something as expensive as a new bike, I have to have a good excuse. If I can convince my wife that the type of material on my current bike has a short fatigue life and I might suffer a catastrophic crash, I will be able to upgrade to a newer bike.:) If I have a bike that is 20 years old, weighs 10 pounds more than the newer bikes but is known to have an infinate fatigue life, I am going to have a hard time convincing the wife to let me upgrade. I figure if the fatigue life is short, I will be able to upgrade more often. Of course this is only valid if you have the financial means to upgrade at will.

Note:

This post is mostly sarcasm. Please don't flame me.:)

Andrew