Is there any difference in expected life of a frame based on what material it's made out of?

Is there a point where a frame is worn out and no longer safe to ride? Is this based on miles?

Good question. I have friends who ride vintage bikes without any problem, but none of them is a carbon monocoque. One is a carbon-tubed Trek with lugs. Age seems not to be a factor.

I'm curious about miles and weathering, though, especially among nekked carbon frames.

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I want to know if there are actual definitive studies done to verify any claims about life expectancy. Too lazy to Google...stil I see this going to

Design is as important as material, so you can't speculate on lifespan based on the material.

Miles matter, but so does rider weight, strength, and terrain.

Whenever a crack develops, the frame should be repaired or replaced. Until then, ride on...

It lasts until you break it. Metallurgists will tell you about the fatigue characteristics of the various metals, but a well-made frame in any of the commonly-used materials is likely to last you a lifetime unless damaged. Just don't store a steel frame under water.

It's weird that a lot of people still think that CF is weaker compared to alu or steel. Yesterday while doing a training ride at a road course we have in a wildflower preserve that only bikes are allowed I overheard two guys talking at the rest point and I guess one of them bought a new bike and the other tells him that it was a good thing he bought alu because CF frames are too brittle.

I think it depends.

Carbon probably has a shorter lifespan just due to the inevitable crashes etc.

I am unaware of any scientific studies, however.

FWIW I just replaced my 25 year old steel frame road bike. It has not "worn" out or rusted, just needed a new one. I chose Ti and am hoping it lasts 25 years as well.

Oh yeah...

Of course, it is always preferable to retire the frame the day BEFORE it cracks!

If it was not worn out or rusted, what necessitated the new frame?

For the record, I once had an aluminum frame that cracked about once every 30 days at the head tube / top tube junction. Materials aren't the whole story.

Asking this question is like asking how long does a 700x23 tire last. It varies... I do know that in my instruction booklet for my Felt F75 there was a disclaimer about how higher performance bikes do not last as long as others.

I think most bikes--C, Ti, steel, Al--will last indefinitely until they are damaged. Probably steel or Ti will last the longest just because they are easier to repair back to truly original condition with quality assurance.

I know several Ti's that are about 15 to 25 years old and they have been repaired several times by replacing the original damaged tubes and it just doesn't show. I had my steel bike rebuilt to original specs after the seat tube cracked.

I also had epoxy reinfused into my C bike just to be safe when it got dinged on the side of the top tube. However, the repair is visible on close inspection.

I have heard that Al fatigues and seen several well-used (but not very old) Al mountain bikes cracked at the bottom bracket so maybe it's true. But counter to this is a friend's Al road bike with over 100,000 miles on it so...?

Depends on how much power you put out, how many hard holes you ride over, if you crash it etc. Then with everything, sometimes there's a small defect that magnifies over time. Of course some will ride the frame every day for 2 hours or 6 hours and some will not touch it for months.

Then there's the construction of the walls and joins on the frames. Some steel and aluminum frames are incredibly thin, while some cf frames are noticeably thicker. I have a friend that is still putting thousands of miles a year on his Giant CFR Two from 1994, I have another friend that broke an aluminum frame each year for three years in a row (and then switched to cf). It's all relative.

Frames don't change but people do. I certainly don't ride the same geo I did 10 years ago.

+/- 267,000 miles. Again, wind conditions will play a big part in its overall durability. Do you wear bibs or just shorts? Ryanf, these are great questions.

frames last as long as you can't afford the next new latest/greatest out there... when you can your existing frame is automatically stressed and old....

My frame is falling apart at all the joints after 60 years of use.

All my bikes are fine.

Love it.

Anywhere from several seconds to centuries.

YMMV.

Very few people buy a bike and ride it until the frame breaks from normal wear and tear. It happens, I'm sure, but that is rare. Frames get damaged falling over in the garage, crashes, hitting holes or obstacles in the road, etc, and frames get replaced for something newer. The question for me about a frame is how well can it take "normal" abuse - an inexperienced mechanic, improperly loaded onto a stand or bike rack, getting knocked over or surviving crashes.

So what do you think of the discussion so far laserfj?

English or Metric?

CF just doesn't tolerate imperfections in workmanship too well, so you have to go with the utmost reputable makers. Small errors can lead to major failures. Boeing tried to make a wing out of CF when they were competing for the JSF contract but they kept having problems when they put it under sonar and it revealed imperfections in the molding process. They've gotten better at it but it's all in the process.

Well... when I asked the question, I wasn't sure to expect (thus, I asked it). I have an aluminum frame that I ride on that I bought that had about 10,000 miles already on it when I bought it. It's still in pretty good shape and I take good care of it. Really was just trying to get a feel for how long I should expect it to last. It sounds like it can depend more on craftsmanship than material.

Also, it feels a little weird that you're asking me what I think of this discussion...

Just sayin...