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Do Steel Frames Wear Out?

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Do Steel Frames Wear Out?

Old 11-19-17, 09:06 AM
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Colnago Mixte
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Do Steel Frames Wear Out?

I think the general consensus here, and in the vintage bike community is “No they do not”. As Jobst Brandt puts it:

The reason this was not in the FAQ may be that the whole subject is so preposterous to engineers, metallurgists, and physicists that they, the people who might explain it, are generally not inclined to bother discussing whether "the moon is made of green cheese" or not.
Frames "going soft" by Jobst Brandt

However, while browsing a physics forum, I saw some interesting counter-arguments, with regard to whether springs wear out or not:

It's been decades since I've studied such things, but my best guess would be "work hardening". Similar to bending a paperclip over and over again, until it breaks. Each time a spring is compressed or stretched, atoms realign themselves into a slightly more crystalline structure. Crystal's make very poor springs from what I've heard. That's the way I remember it anyways.
And

Ever sleep on a spring mattress? Which parts become less "springy" over time when force is applied? Seems like the same elements would apply if you stretched it... in both cases you're taking its natural/original state and changing it with unnatural force, which it adapts to on a structural level which changes it fundamentally from it's original and optimal form.
And:

Valve springs do fail. If you take a spring with 1,000,000 miles on it and compare it to a new spring, the new spring will require significantly more pressure to compress. The only reason valve spring failure is not more common is that the rest of the car wears out first.

A previous post mentioned gradual hardening of a spring over many cycles but this cannot be the cause of valve spring failure because they get softer with time. The same thing applies to suspension springs. They oscillate every few inches while driving, but seldom break except due to rust. However, if a large person drives a small car, after several years the drivers side of the car will sit lower due to greater spring fatigue on that side.
Read more here:

https://www.physicsforums.com/thread...ar-out.519055/

I am inclined to think that steel frames do wear out from normal use. No, hundreds of thousands or millions of flex cycles won’t magically change the chemical properties of the steel, like Superman squeezing a lump of coal and turning it into a diamond. But I do think there are changes at work that affect the ride of old frames, I just have not quite nailed down the exact mechanism.

In the interests of clarity, I should mention that when I refer to a steel frame “wearing out” after many years of use, I’m talking about a frame that just doesn’t “snap back” quite as forcefully when flexed as it did when it was new. Yes, it still flexes, but the “liveliness” seems no longer there.

And when I refer to a “frame”, I’m talking about not just the steel tubing used, I’m also including the stiffness of the welds, and the lugs. Nobody ever talks about the welds or lugs weakening over time, so I am specifically pointing out this factor as a possible cause.

Many frames have rider weight limits. What happens if a 300 pound rider races the entire Tour De France route on a frame with a 150 lb weight limit, and manages to do so without snapping the frame? Will such a frame ever be the same again?

According to naysayers, the properties of the steel tubing used to construct the frame remain unchanged, and the bike ought to, in theory, ride exactly the same as it did the day it rolled off the assembly line. And any thinking anything to the contrary is like “discussing whether the moon is made of green cheese or not.”

I have my doubts. And racing teams also had their doubts, and used to routinely replace steel frames every season (when people still raced on steel frames). BF members, you people presumably ride those old bikes occasionally, what say you?
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Old 11-19-17, 09:15 AM
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AFAICT they ride the same until a fatigue crack starts to form somewhere. Then the ride quality changes rapidly until the frame fails.
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Old 11-19-17, 09:23 AM
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Originally Posted by Colnago Mixte View Post
BF members, you people presumably ride those old bikes occasionally, what say you?
With only 43 and 40 years of continual service on a couple of mine including being road raced and ridden as fixed gears, so far so good.

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Old 11-19-17, 09:27 AM
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The only thing that wears out over time, is the rider.
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Old 11-19-17, 09:32 AM
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Crystal's make very poor springs from what I've heard. That's the way I remember it anyways.
His command of solid-state physics is no better than his grasp of punctuation, or grammar.
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Old 11-19-17, 09:51 AM
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I'm on the "No, they do not" side, but acknowledge the difficulty of knowing for certain due to the very few frames encountered that had continuous use through out their lifetime.

Some vintage frames spend decades, unridden, in storage . If conditions are dry, the frame is fine. But if left out in the elements for a few seasons, they degrade quickly. Rust is our enemy. Don
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Old 11-19-17, 10:15 AM
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Making comparisons between bicycle frames, valves springs, etc. is foolish and naive.
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Old 11-19-17, 10:17 AM
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Originally Posted by 16Victor View Post
Making comparisons between bicycle frames, valves springs, etc. is foolish and naive.
You might as well throw a bridge into the mix for good measure. The alloys, condition (crystal structure and arrangement), joining methods, service conditions, and repetitive stresses are wildly different.

Because I don't remember a lot of the details of my engineering education so long ago, let me be anecdotal: if we were anywhere near the point of changing the dynamic response of the frame in normal (within specified limits of frame material and joining method, assuming no latent defects) service over time, we'd be seeing see a hell of a lot more failures.

I would love to be proven wrong on the above but it would have to be supported with some solid discussion on materials and physics. It would be a great learning experience.
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Old 11-19-17, 10:23 AM
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It's a pretty basic point of materials science and metallurgy that if you bend an elastic material "a little bit," you are doing no significant damage to the metal and its springiness will not be degraded perceptibly, even with instrumentation in a proper laboratory. The trick in frame design and frame tube design is to make sure that the expected flexings of a frame in touring, racing, or whatever use with riders of anticipated weight (or sometimes maximum anticipated weight) can't bend the frame beyond the "a little bit."

If you bend a metal part such as a frame tube far beyond this small level of flex, the inherent metal characteristics will be changed. It will become less springy, it may take on a permanent change of shape (aka cold-setting), and it may even fracture (the paper clip situation).

Again, if the frame is designed correctly and used as expected, it's not going to degrade in the frame tubes, over a long lifetime.

At the ends of the frame tubes, we have butts, lugs, and miters, and the materials and changes of cross-section cause "stress risers," where the stresses of such little flexings are concentrated. There are a lot of little tricks in frame building to manage stress at these locations, which will reduce the flexing stresses and increase lifetime.

Also at the joints, there's just the possibility for poor workmanship, which can make a poorly filled joint, or can overheat the steel and change its inherent characteristics for the worse. Its more likely that fatigue will cause a failure of a frame at a lug, the end of a butt, a braze-on, or in a joint, that in the middle of a well-made frame tube.

Go to Wiki and look up Fatigue (material). There are other articles which may be more basic, and some which have the math.

Also look at "Young's Modulus" or "Modulus of Elasticity."
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Old 11-19-17, 10:24 AM
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Originally Posted by 16Victor View Post
Making comparisons between bicycle frames, valves springs, etc. is foolish and naive.
Actually it's not - the physics is the same.
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Old 11-19-17, 10:37 AM
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Originally Posted by Road Fan View Post
Actually it's not - the physics is the same.
You are quite correct. It was badly stated on my part, I really meant to convey that drawing conclusions from comparisons using wildly different sets of input parameters is invalid.
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Old 11-19-17, 10:53 AM
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As long as they're used within the design limits, they will last something short of forever. The design limits are generous, so thatg's true for most users.

However, heavier riders or those hauling cargo on a regular basis will see shorter life. Not in terms of them going "soft" or otherwise changing ride properties, but in premature failures, usually at joints. Fortunately, whether by design or happenstance, the first failures tend to be at the least critical joints, or preceded by a long period of visible crack formation so injury due to steel frame failure is relatively rare.
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Old 11-19-17, 11:25 AM
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Yeah, they can wear out. In reality, most will last the life of a rider.

Others have commented on the technical aspects of why.

In my experience, steel frames break from inadequacies in the manufacturing process.
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Old 11-19-17, 11:43 AM
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The question asked here simplifies things too much. Let's compare two different road bikes, same size, miles and road conditions. My standard 531 (I believe; in those days Peter did not sticker his bikes unless you requested it and paid extra - he wanted the freedom to select the best tubes for the application) and a same era Peugoet PX-10. The two bikes have similar Nervex lugs. Let's say the PX-10 has been ridden by a strong, not especially smooth 225# rider. My Mooney by me, a 155, long, skinny climber with good pedaling style from many years of fix gear as well as coaches who preached "suplesse".

Bikes are now 38 years old with 46,000 miles on them. They have climbed many mountains, done some lightish touring, ridden gravel including a recent near epic 30 miler. Some very hard rains.

Now let's look at the one signifant difference between these bikes. The tubes. Same alloy and drawing process. 531 double butted. Tubes Reynolds had been making for 40 years. But, the Mooney is English standard road. The PX-10 French standard pursuit. Peugeot had an agreement with Reynolds to that tubing for years. Reynolds would not sell that tubing to anyone else for anything but track use. That rumor that PX-10s were lighter and more flexible than other 531 bikes? They were.

Back to our comparison. My Mooney has been ridden, on the big scale of thing, lightly because it has only been ridden by skinny, slow twitch, no sprint me. Barring a couple of hard crashes, it has not seen stresses that come anywhere near the fatigue limit of 531 steel. (Peter's meticulous workmanship and me not selecting or having the means to pay for any exotic lug cutouts or filing helps in this regard. His work on my bike is business-like and very well done. Plenty of lug left. Now that PX-10, a production bike with nowhere near the level of attention has been ridden far harder. Given its considerably lighter tubing, it isn't hard to imagine that the steel has seen well over the fatigue limit many times just being ridden, especially in the heat affected zone around the lugs. (I'm guessing the PX-10s were brass soldered, my Mooney is silver soldered.)

And this comparison doesn't address shoddy workmanship, solder voids, poor tubing and lug fits or poor design. All of these can push the steel to above fatigue limit stresses in local areas, perhaps initiating some very small cracks and a little "softness" to the ride.

Conclusion: with the proper design and build for the intended use and rider, a steel bike can be made that keeps the working stresses below the fatigue limit. That bike is very likely to go a long, long ways with no detectable difference in "feel". (Don't know the rider or future use but want that feel to never change? Build the bike strong, stiff (and heavy).

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Old 11-19-17, 12:28 PM
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My grandfather rode the same Oscar Wastyn built frame for nearly 60 years, and put (conservatively) a quarter of a million miles on it. It outlasted him.
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Old 11-19-17, 01:13 PM
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Originally Posted by prathmann View Post
AFAICT they ride the same until a fatigue crack starts to form somewhere. Then the ride quality changes rapidly until the frame fails.
Steel can take flexes indefinitely without cracking as long as they remain below the fatigue limit:

"Ferrous alloys and titanium alloys have a distinct limit, an amplitude below which there appears to be no number of cycles that will cause failure. Other structural metals such as aluminium and copper do not have a distinct limit and will eventually fail even from small stress amplitudes."

I suspect the apparent "softening" of a steel frame over time is more likely a manifestation of the "N+1" syndrome than anything else.
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Old 11-19-17, 03:14 PM
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Originally Posted by 79pmooney View Post
The question asked here simplifies things too much. Let's compare two different road bikes, same size, miles and road conditions. My standard 531 (I believe; in those days Peter did not sticker his bikes unless you requested it and paid extra - he wanted the freedom to select the best tubes for the application) and a same era Peugoet PX-10. ...
Now let's look at the one signifant difference between these bikes. The tubes. Same alloy and drawing process. 531 double butted. Tubes Reynolds had been making for 40 years. But, the Mooney is English standard road. The PX-10 French standard pursuit. Peugeot had an agreement with Reynolds to that tubing for years. Reynolds would not sell that tubing to anyone else for anything but track use. That rumor that PX-10s were lighter and more flexible than other 531 bikes? They were.

Ben
Was the PX-10 lighter simply because it had hard metric 28.0mm diameter main tubes instead of the more common 28.6? OK, that's only about a 2 percent difference, or about an ounce in a road frame, so maybe there was more to it.

All I know is that I have broken two road frames, evidently merely by riding them. I have done a lot of hill work, including out-of-saddle climbs, but I am not a big guy, having consistently weighed between 140 and 150 lbs. for the past 50 years.

1. double-butted CrMo late 1970 Kawamura frame used by Nishiki in my 1971 Semi-Pro -- the seat tube lug broke away from the bottom bracket shell at the 20 year / 40K mile mark.

2. ca. 1973 Peugeot UO-8 -- the chainstay cracked between the tire and chainring clearance dimples at the 20 year / 20K (??) mile mark.
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Old 11-19-17, 03:15 PM
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Originally Posted by JohnDThompson View Post
Steel can take flexes indefinitely without cracking as long as they remain below the fatigue limit:

"Ferrous alloys and titanium alloys have a distinct limit, an amplitude below which there appears to be no number of cycles that will cause failure. Other structural metals such as aluminium and copper do not have a distinct limit and will eventually fail even from small stress amplitudes."

I suspect the apparent "softening" of a steel frame over time is more likely a manifestation of the "N+1" syndrome than anything else.
That's the kind of statement I was hoping to find quickly by looking at Wikipedia!
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Old 11-19-17, 03:42 PM
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If I had a frame made of 531 that was well designed, well made and carefully maintained - though constantly ridden within its intended limits - that was made in 1517 (the year), I would ride it cautiously. I'd be more concerned about how the joinery was holding up than the tubing - unless I saw some damage.

Note that I am not a chemist, nor am I a physicist (that quantum gibberish spoiled it all), nor do I enjoy engaging in protracted philosophical arguments merely for the sake of demonstrating mictural superiority.
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Old 11-19-17, 03:54 PM
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Originally Posted by John E View Post
Was the PX-10 lighter simply because it had hard metric 28.0mm diameter main tubes instead of the more common 28.6? OK, that's only about a 2 percent difference, or about an ounce in a road frame, so maybe there was more to it.

All I know is that I have broken two road frames, evidently merely by riding them. I have done a lot of hill work, including out-of-saddle climbs, but I am not a big guy, having consistently weighed between 140 and 150 lbs. for the past 50 years.

1. double-butted CrMo late 1970 Kawamura frame used by Nishiki in my 1971 Semi-Pro -- the seat tube lug broke away from the bottom bracket shell at the 20 year / 40K mile mark.

2. ca. 1973 Peugeot UO-8 -- the chainstay cracked between the tire and chainring clearance dimples at the 20 year / 20K (??) mile mark.
The PX-10 used tubing Reynolds drawn to make pursuit track bikes, considerably thinner that their road tubings. On top of the thinner tubing, it was also smaller diameter. (Reynolds wouldn't sell their English diameter pursuit tubing for road use either.)

1. double-butted CrMo late 1970 Kawamura frame used by Nishiki in my 1971 Semi-Pro -- the seat tube lug broke away from the bottom bracket shell at the 20 year / 40K mile mark. Sounds like a quality control issue. (My 1976 Fuji seattube broke almost in the same place. I never heard of later Fulis breaking their. I believed they payed more attention to BB tube fit details.)

2. ca. 1973 Peugeot UO-8 -- the chainstay cracked between the tire and chainring clearance dimples at the 20 year / 20K (??) mile mark. Those UO-8s were made from not very high strength tubing. Mine broke almost the same place about 1000 miles sooner. It also took on new alignments after harder crashes. (It was my winter bike of my no-car Boston and Ann Arbor days as well as my bad weather training bike my three years of racing. I called it a slinky. Mostly because of the very, very low BB and long wheelbase but also because there was no useful plane around which anything was centered or symmetrical. Riding no-hands? Only when the last crash magically added a new fudge factor that allowed it.)

Ben
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Old 11-19-17, 04:06 PM
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Originally Posted by John E View Post
Was the PX-10 lighter simply because it had hard metric 28.0mm diameter main tubes instead of the more common 28.6? OK, that's only about a 2 percent difference, or about an ounce in a road frame, so maybe there was more to it.
The frame weights might not have differed all that much, but the component weights might have. Nobody I knew weighed bike components back in the seventies (some had gram scales, but they used them for other things), but I was under the impression that the French components on PX-10s and other high-end French bikes were lighter than the equivalent Campy Record parts.

Someone reading this thread will probably know the answer to this question:
Correct that the first time that Reynolds made metric-dimension road bike tubing available to bike manufacturers other than Peugeot was when they introduced 753 tubing?
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Old 11-19-17, 04:10 PM
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I had a couple of cracks on my 70s Super Course (main triangle, 531) at the seat stay, seat tube junction, both sides. I think it was mainly cosmetic, but I stripped the paint and had them rebrazed anyway. It's probably now good for another 50 years. This was a "found" frame, so I have no idea of its history. It is a great riding frame, smooth, compliant, but just stiff enough for me. Before and after repair pics below.
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Old 11-19-17, 04:52 PM
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My oldest bike is 61 years old with a history of abuse followed by neglect over and over again. I don‘t see/feel any signs of the frame being worn.
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Old 11-19-17, 05:06 PM
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Originally Posted by
[URL="https://en.wikipedia.org/wiki/Fatigue_limit"
"Ferrous alloys and titanium alloys have a distinct limit, an amplitude below which there appears to be no number of cycles that will cause failure. Other structural metals such as aluminium and copper do not have a distinct limit and will eventually fail even from small stress amplitudes."[/URL]

I suspect the apparent "softening" of a steel frame over time is more likely a manifestation of the "N+1" syndrome than anything else.
John is right... theoretically, if you stay below the fatigue limit of the STEEL MATERIAL, the STEEL MATERIAL would never fail. Once you start to braze that material, and create joints using a mixture of various metals, using various levels of quality craftsmanship, etc.... the variables are extensive and the equations governing things become complex (so complex as being impossible to determine).

ALUMINUM MATERIAL is a whole other material; with aluminum no matter how small the load place on the material, the material will eventually fail. It may take 10,000 human lifetimes to cycle (not bicycle cycle, but the "applying a load, then removing the load" cycle) the frame enough times to fail. But, in theory, it will eventually fail.

So steel, in theory, will not "wear out", and aluminum, in theory, will "wear out"... problem is, actual life isn't theory. Frames are not just the material from which they are constructed. In actual life, with so many variables, and so complex interactions, your mileage with either material is going to be a crap shoot.

I would say, if you wear a bike out, and you don't get injured in the process, you have sincere admiration.
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Old 11-19-17, 07:16 PM
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Originally Posted by uncle uncle View Post
ALUMINUM MATERIAL is a whole other material; with aluminum no matter how small the load place on the material, the material will eventually fail. It may take 10,000 human lifetimes to cycle (not bicycle cycle, but the "applying a load, then removing the load" cycle) the frame enough times to fail. But, in theory, it will eventually fail.

Does anyone know if adding bits of other metals to an aluminium alloy mix, significantly increases the lifespan and if so, whether this is being used in bicycle tubing today?
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