Frame durability -- A great study shines light on retro frames
#26
A bike frame - steel ones at least - are fairly complex structures and it's really hard to simulate the loads imposed by a rider on real roads.
However for a properly built frame, where the front forks and rear dropouts are firmly held and deflection loads imposed at the bottom bracket, the structure should still behave according to Hooke's law which is shown below. "Stress" is the load applied to the frame, and "strain" is the deflection measured in response to that load.
Looking at the stress / strain curve below, if the loads imposed are in the range of A and B, the frame is being loaded well within the elastic range, and will spring back with no permanent deformation. Fatigue effects for loads in this range will not occur for millions - 10s of millions - of load cycles.
HOWEVER once you go beyond "C" on the stress / stain curve, then the frame may be permanently distorted (not return to original unloaded position) and fatigue cycles build up very quickly.
the trick in load testing is to go as close to "C" as possible, still staying in the elastic region (where the frame springs back) and then applying hundreds of thousands of load cycles at that level until a crack appears.
![](https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin/483x284/hookes_law_2c7b65648aa17a0391b5b907cff2b1fe4b8ecbd6.jpg)
However for a properly built frame, where the front forks and rear dropouts are firmly held and deflection loads imposed at the bottom bracket, the structure should still behave according to Hooke's law which is shown below. "Stress" is the load applied to the frame, and "strain" is the deflection measured in response to that load.
Looking at the stress / strain curve below, if the loads imposed are in the range of A and B, the frame is being loaded well within the elastic range, and will spring back with no permanent deformation. Fatigue effects for loads in this range will not occur for millions - 10s of millions - of load cycles.
HOWEVER once you go beyond "C" on the stress / stain curve, then the frame may be permanently distorted (not return to original unloaded position) and fatigue cycles build up very quickly.
the trick in load testing is to go as close to "C" as possible, still staying in the elastic region (where the frame springs back) and then applying hundreds of thousands of load cycles at that level until a crack appears.
![](https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin/483x284/hookes_law_2c7b65648aa17a0391b5b907cff2b1fe4b8ecbd6.jpg)
#27
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Not everyone rides with performance as the main motivator for equipment. This can be seen even with those who own superbikes, in the fact that they often also have an older bike, rain bike, pub bike, etc etc.
I think a lot of times the reason for buying or continuing to own older equipment in a mix of nostalgia and appearance.
Here are 2 that have been modernized, and both cost less than $1000 once completed. Would I be faster on a 2018 Roubaix 105 than the CAAD with Ultegra? Eh...really not so sure. Perhaps a handful of seconds over a larger handful of miles?...or maybe not.
'97 CAAD3 frame. Added a carbon fork, 2x11 Ultegra shifting, and painted it.
![](https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin/2000x1500/4e578b49_c85b_4f00_9d17_9e7179f89f35_b75a8d7e0ba02dfec02b5f77f80cd9c6a3340436_jpeg_640568fda6a3ee079410d0eae8d06a81196c334f.jpg)
'89 Japanese contract built road frame. 2x11 105 shifting and powdercoated it.
![](https://cimg1.ibsrv.net/gimg/bikeforums.net-vbulletin/1999x1124/20210512_172906_0bf59ffbf4d3d11821a62b19dadc0d937228249e_c3ec313ab45299ff697312069e769117e2bdae53_3b6d6a1a693fadbce21e4d650a441b8efdee8ee1_39752d361108b0ab4a40d667448652cecb6088bf.jpg)
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#28
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I have a 40 yo Japanese race bike that was close to the best of the best small diameter tubed steel bikes. In other words, the apex of about 80 years of development. The ride is pure race. Just about perfect. The bike calls up every watt I have to offer and lays it on the road. Yes, new bikes are lighter, more aero and probably a few other good things. Probably room for bigger tires so the rider can safely pay less attention. I ride this bike to feel "the ride" I remember and loved from racing in the '70s. And this bike is better.
The bike had been abused. Left outside for a long time, something steel doesn't like. It may fail on me. But being less than "on the edge", that failure probably won't be sudden. I may well get warning. It probably won't be catastrophic. So I'll pay attention but ride it perhaps the rest of my days as a good day special ride bike. ("Less than on the edge" - Miyata at the time felt the best race bikes weren't the lightest. This bike is in no way "marginal". It is stiff.)
The bike had been abused. Left outside for a long time, something steel doesn't like. It may fail on me. But being less than "on the edge", that failure probably won't be sudden. I may well get warning. It probably won't be catastrophic. So I'll pay attention but ride it perhaps the rest of my days as a good day special ride bike. ("Less than on the edge" - Miyata at the time felt the best race bikes weren't the lightest. This bike is in no way "marginal". It is stiff.)
#29
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Thread Starter
It surprises me more people aren't scouring the markets for road frames like this one.
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#31
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To me, a bike that was A Good Bike 40 years ago - well made, well-equipped, etc. - and that is functioning now as it was when new is still A Good Bike. The fact that there are newer bikes that may be "better" in every measurable way - lighter, better brakes, more useful gears, better ergonomics - doesn't make the 40 year old bike A Bad Bike.
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#32
Senior Member
I think either old bikes "speak to you", or they don't.
To me, a bike that was A Good Bike 40 years ago - well made, well-equipped, etc. - and that is functioning now as it was when new is still A Good Bike. The fact that there are newer bikes that may be "better" in every measurable way - lighter, better brakes, more useful gears, better ergonomics - doesn't make the 40 year old bike A Bad Bike.
To me, a bike that was A Good Bike 40 years ago - well made, well-equipped, etc. - and that is functioning now as it was when new is still A Good Bike. The fact that there are newer bikes that may be "better" in every measurable way - lighter, better brakes, more useful gears, better ergonomics - doesn't make the 40 year old bike A Bad Bike.
#33
Yeah, but what is the best frame material?
![Innocent](images/smilies/innocent.gif)
#34
Senior Member
#35
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Not everyone rides with performance as the main motivator for equipment. This can be seen even with those who own superbikes, in the fact that they often also have an older bike, rain bike, pub bike, etc etc.
I think a lot of times the reason for buying or continuing to own older equipment in a mix of nostalgia and appearance.
Here are 2 that have been modernized, and both cost less than $1000 once completed. Would I be faster on a 2018 Roubaix 105 than the CAAD with Ultegra? Eh...really not so sure. Perhaps a handful of seconds over a larger handful of miles?...or maybe not.
'97 CAAD3 frame. Added a carbon fork, 2x11 Ultegra shifting, and painted it.
![](https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin/2000x1500/4e578b49_c85b_4f00_9d17_9e7179f89f35_b75a8d7e0ba02dfec02b5f77f80cd9c6a3340436_jpeg_640568fda6a3ee079410d0eae8d06a81196c334f.jpg)
- Easy maintenance
- Fun project
- Appearance
- Brand/model history
Not everyone rides with performance as the main motivator for equipment. This can be seen even with those who own superbikes, in the fact that they often also have an older bike, rain bike, pub bike, etc etc.
I think a lot of times the reason for buying or continuing to own older equipment in a mix of nostalgia and appearance.
Here are 2 that have been modernized, and both cost less than $1000 once completed. Would I be faster on a 2018 Roubaix 105 than the CAAD with Ultegra? Eh...really not so sure. Perhaps a handful of seconds over a larger handful of miles?...or maybe not.
'97 CAAD3 frame. Added a carbon fork, 2x11 Ultegra shifting, and painted it.
![](https://cimg6.ibsrv.net/gimg/bikeforums.net-vbulletin/2000x1500/4e578b49_c85b_4f00_9d17_9e7179f89f35_b75a8d7e0ba02dfec02b5f77f80cd9c6a3340436_jpeg_640568fda6a3ee079410d0eae8d06a81196c334f.jpg)
Yes, this is exactly what I was getting at -- I think if you spent $12,000 on a new bike the advantages over this CAAD3 would be up for debate. Personally, I think this one is the winner for its history of handmade craftsmanship, proven durability, and classic lines.
It surprises me more people aren't scouring the markets for road frames like this one.
It surprises me more people aren't scouring the markets for road frames like this one.
Last edited by Camilo; 05-31-23 at 11:01 PM.
#36
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The fact that some frame materials performed a certain way in a certain test ... how is it relevant to most riders? Unless we are talking downhill bikes, as [MENTION=175341]icemilkcoffee[/MENTION] mentions, most riders aren't hitting the frames with the kind of loads which will cause fatigue failure. Sure, rust or bad welds or bad layup or improperly spread epoxy or whatever might cause failure ... or a crash .... but for most riders total frame failure seems to be pretty rare.
In fact, as has been mentioned in other threads, what you do with the material is as important as the material itself. The design of the frame and its intended uses matter more than what it is made from, assuming it is made well.
Also "old vs. new" is just one of those made-up divisive debate topics which people who are not at peace like to throw around to stir things up. "Suitable to its use" is actually a thing .... if your bike works in the way to intend it to work for the application you choose, it is a "good bike" (IMO.)
My point when I entered this thread was that A.) what certain frames did in a certain test 25 years ago has nothing to do with how most bikes then or now perform---as I said, most of us Never stress a bike until the frame breaks, and when we do it is usually an accident (and don't bother with your anecdotes .... in a large enough pool there will always be a few outliers, but as i said ... "most of us" ... ) and,
B.) as the OP noted, people who have prejudices about frame materials are not going to change their minds just because of facts.
I have steel, aluminum, and carbon bikes, some 40 years old, some four years old. I enjoy riding each of them. I have ridden i cannot even estimate how many different bikes, and I have only broken one frame, but I had to get run over by a semi-trailer to do it. I have bent a bunch of frames in various ways, sometimes irreparably ... but that is still just anecdotal.
Basically, bikes are bikes and if you like riding your bike, good for you. What some scientists said 30 years ago doesn't seem relevant today, and doesn't even seem to have been relevant then, because honest people knew then (and still know) that most bikes didn't break unless the rider actively broke them.
Just my view.
In fact, as has been mentioned in other threads, what you do with the material is as important as the material itself. The design of the frame and its intended uses matter more than what it is made from, assuming it is made well.
Also "old vs. new" is just one of those made-up divisive debate topics which people who are not at peace like to throw around to stir things up. "Suitable to its use" is actually a thing .... if your bike works in the way to intend it to work for the application you choose, it is a "good bike" (IMO.)
My point when I entered this thread was that A.) what certain frames did in a certain test 25 years ago has nothing to do with how most bikes then or now perform---as I said, most of us Never stress a bike until the frame breaks, and when we do it is usually an accident (and don't bother with your anecdotes .... in a large enough pool there will always be a few outliers, but as i said ... "most of us" ... ) and,
B.) as the OP noted, people who have prejudices about frame materials are not going to change their minds just because of facts.
I have steel, aluminum, and carbon bikes, some 40 years old, some four years old. I enjoy riding each of them. I have ridden i cannot even estimate how many different bikes, and I have only broken one frame, but I had to get run over by a semi-trailer to do it. I have bent a bunch of frames in various ways, sometimes irreparably ... but that is still just anecdotal.
Basically, bikes are bikes and if you like riding your bike, good for you. What some scientists said 30 years ago doesn't seem relevant today, and doesn't even seem to have been relevant then, because honest people knew then (and still know) that most bikes didn't break unless the rider actively broke them.
Just my view.
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#37
Junior Member
I only broke two frames when I was a kid, both were Sears Free Spirit 20" wheel size bikes. I was really abusing them, jumping on a long ramp as far as I could and landing hard. Both frames went many, many jumps, 100's before the frames finally cracked. These bikes were not designed to do what i was doing to them, yet they still survived a long time. My dad then bought me a beefier frame and I jumped that one more and farther than the other two and besides bending a lot of cranks from hard landings, the frame never broke or cracked. I'm a bit confused since getting into this road/gravel biking thing. What is anyone besides crashing, doing to crack these frames? Is the simple act of sprinting, flexing the frames to the point of failure?
#38
I mean- a 2012 Hyundai Accent will most likely out-speed, out-economy, out-reliable, out-safety and out-everything-else a 1967 MGB GT. But for the same money, which one do you really want to be seen in?
#39
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I guess if you're more interested in showing off, you'll drive the car that leaks oil and has dodgy electronics.
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#40
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#41
Senior Member
I think the opposite way. Why would you buy some generic ho-hum mid range bike that was stamped out overseas, when for that same $1000 you can buy a nice good classic Serotta or Paramount that was made by hand right here in the USA with the highest end components available at the time. You can see, touch and feel the pride of workmanship everywhere on these bike.
I mean- a 2012 Hyundai Accent will most likely out-speed, out-economy, out-reliable, out-safety and out-everything-else a 1967 MGB GT. But for the same money, which one do you really want to be seen in?
I mean- a 2012 Hyundai Accent will most likely out-speed, out-economy, out-reliable, out-safety and out-everything-else a 1967 MGB GT. But for the same money, which one do you really want to be seen in?
For a small few a bicycle represents a lot more and it’s not about riding or using the bicycle it’s about ownership. Much like camera collectors purchasing a vintage Nikon F2, is not about photography at that point.
Last edited by Atlas Shrugged; 06-01-23 at 10:42 PM.
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#42
With a mighty wind
I’ve been looking for a frame with an aluminum core, wrapped in carbon fiber, with steel lugs.
Any leads?
Any leads?
#43
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#44
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#45
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The fact that some frame materials performed a certain way in a certain test ... how is it relevant to most riders? Unless we are talking downhill bikes, as [MENTION=175341]icemilkcoffee[/MENTION] mentions, most riders aren't hitting the frames with the kind of loads which will cause fatigue failure.
I don't think one can say with confidence that fatigue inducing loads never occur under normal riding conditions. Failures near bottom brackets of steel, titanium, and aluminum frames suggests the cycling loads from pedaling are enough to do the trick.
![](https://cimg2.ibsrv.net/gimg/bikeforums.net-vbulletin/1600x1200/crackedframe2_f8ad04cee41eeb488d78f21f8040942308e48f87.jpg)
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#46
Senior Member
If "most riders" is the criterion, then even he weakest bike frame is safe from failure. Most bikes get ridden a handful of miles per year.
I don't think one can say with confidence that fatigue inducing loads never occur under normal riding conditions. Failures near bottom brackets of steel, titanium, and aluminum frames suggest the cycling loads from pedaling are enough to do the trick.
I don't think one can say with confidence that fatigue inducing loads never occur under normal riding conditions. Failures near bottom brackets of steel, titanium, and aluminum frames suggest the cycling loads from pedaling are enough to do the trick.
One great thing about the new design criteria emphasizing aerodynamics, comfort, and gravel capability over lightness---bikes are almost certainly becoming stronger and more resistant to fatigue failures.
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#47
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#48
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I think the opposite way. Why would you buy some generic ho-hum mid range bike that was stamped out overseas, when for that same $1000 you can buy a nice good classic Serotta or Paramount that was made by hand right here in the USA with the highest end components available at the time. You can see, touch and feel the pride of workmanship everywhere on these bike.
The old bike (and I have a couple) might be really well-engineered and constructed, but it will also be the pinnacle of a long-outmoded standard ... my Cannondale will never have more than seven cogs, while my Raleigh can use a modern drive train only because i 're-engineered" the frame ...... and both have limits on tire width based on the technologies and customs which were considered "best" 40 years ago.
The fact that one frame was built by more by hand and one more by machine doesn't mean one is better or worse ... for many years there was a joke among the owners of Italian sports cars that they had "hand-built character" because of sloppy construction in the interior .... and while a straight-tubed frame might be woderful, a modern, hydro-formed aluminum, shaped-steel, or CF frame might be a better frame despite being made by machine---and with CNC tech and such, machine-made parts are a lot better than they ever were ..... And that old bike might have the best parts available 40 years ago, but those parts are pretty lame compared to what is available today---Shimano hasn't been improving its parts for the past several decades because they were better back then.
If I had a whole fleet of cars, I would certainly have a few hand-built rarities .... a Maserati Birdcage, a Mini Cooper SS, a Lamborghini Miura ...... bunch more the longer I think.
Of course, the Maserati would hurt on every bump and break after some number, the Miura overheats, the Mini Cooper is a ball to drive but it is a vintage 1200 cc inline four which is totally outperformed by any modern, CNC-milled motor of the same displacement.
I don't feel special when I ride a vintage bike, nor any bike---because of the bike. I could not care less about the decal on the down tube. Two of my favorite bikes are Chinabombs. As far as the "fun-to-drive" factor .... different machines for different moods, but if I had to rely on only one or two bikes, I would rather get the latest best tech rather than 40-year-old gear .... and in fact, both my 40-year-old bikes have the most modern drive trains I can fit on them. I did decades of friction shifting, weak brakes, and all that .....
Not to say my preferences are anything but mine ... but i want actual function, not flash. I'd rather have wider tires, wider range of gears, better brakes, and cartridge bottom brackets and wheel bearings are lot easier to actually use and maintain than ball-and-cage. Cottered cranks .... no thanks.