Aging alloy frames
 

This is not a question about whether alloy frames can fail. Rather I'd like to hear from you whether there is any significant loss of stiffness in an alloy frame over time (20 years and +/- 15 000 KM in my case) which would have an effect on efficiency, especially in climbing hills and mountains.

My bike is a touring bike (Gary Fisher Utopia) and with my son having recently really got into road cycling I'm wondering if I should consider getting a a more road specific bike (probably a second hand endurance bike). I have to admit that I sort of want to get myself another bike to have a real road one. But I also have to admit that my current bike really goes well on paved roads. So I am sort of trying to see if there are objective criteria for getting another bike.

P.S. My current bike has never had any accidents.

Isn’t that a MTB/hybrid?

The answer is NO.

Your disadvantages climbing on this specific bike will be related to weight, tire width/weight and if you can lockout the fork.

My 90s Cannondale caad3 is a still a stiff frame almost 30 years after it was made.
Stiffer feeling than almost all my steel bikes, even the modern ones.

I have a 1995 Cannondale T700 (alloy, steel fork). That's a touring bike.

I did not measure the "stiffness" when I bought it, so there's no way to tell if there's been "any significant loss of stiffness ... over time" (29+ years > 50,0000 miles). And I can't go by feel because, of course, any changes would be so gradual as to be imperceptible, and would probably be swamped by other factors in any case (I'm on my third set of wheels on the bike, and I've used different tires, different widths of tires, different saddles, replaced the crank, etc.).

Your question is ridiculous. Sorry. If you want a new bike, you'll have to find another excuse.

I had a ‘98 model. Put 10,000 loaded miles on that thing in fewer than 2 years.

Wow. You've mentioned your excursions in threads over the years, but I had no idea you'd ever done that kind of consistent tour mileage. Impressive, to say the least.

If you want a new bike, after 20 years, go get one!

Some of the super serious people I used to ride with did believe this.

I remember conversations about that “this frame has so many miles that it’s gone soft” and that’s why it was being utilized as a winter and early spring training bike.

That was, at least 25 years ago and longer, a prevailing theory.

I’d venture to guess that there’s never been a double blind study on it. Never been a stiffness test of a new frame vs the same frame 25 year later.

There are some other reasons to get a new bike. Frame fit, weight, material properties, compatibility with new parts, and for fun.

If it’s not broken, or breaking (it’s always worthwhile to check for cracks), then it’s fine.

If you want to go road cycling with your son then get a road bike. End of story.

Cannot detect change in ride quality of any frame I have--steel, aluminum, titanium (the CF bikes being too new to count). A couple have > 10k miles, including an aluminum frame, CF fork commuter that endured downtown pavement.

Will suggest must used bikes cared for properly should be fine. Know of a few instances of hyper-miled bikes with failures at welds/lugs but that seems rare, sub 0.1% territory.

Those discussions of frames going soft back then concerned steel frames, though.

Funny, given that steel becomes harder, not softer, if enough force is applied (repeatedly) to deform it.

Some things don't need to be tested, because the answer is obvious from first principles.

Metals do not become soft with use.

BS! Weakened metal due to use is why I don't go into buildings taller than 30 feet!**

https://cimg6.ibsrv.net/gimg/bikefor...2013438202.gif

nuff said.

most of us who ride have more than one bike anyway. i used to buy used bikes to have an extra on hand, which is great if a bike needs repair and i wanna ride right now. even if it is just a flat, nice to grab another bike and get to repairs later.

I would not consider 15,000 km "aging". That's less than a year of riding for some people here.

Aluminum gets harder over time.
I supposed it COULD become stiffer....
Not that you'd ever notice.

Correct. Or put another way, if your Al frame has gotten soft, it must have really flexed a LOT and is now bent.

Thanks. I did 3 long tours between May of 1999 and July of 2000, when I took a couple of years off from the working world. It was my first ever exposure to touring and camping. Got my old job back at the beginning of May, 2001 and hung up my touring shoes as I rebuilt my life. Picked up the pursuit again in 2008. Because of my introduction to the activity, I had never realized that relatively short trips could be fun, but they are.

I pour wine in the tubes of my alloy frames

the frame then gets better with age

I heard from a Luddite that putting your alloy frame in an oak barrel for 12 years will make all your rides thereafter perfectly smooth.

As a mechanical engineer I can tell you that aluminum frames can fatigue and that is a factor in weakening aluminum over time, most notably with cyclic loading and/or stresses. This lead to fatigue failures we see as cracks. That said with average weight I have an awful lot of road miles on my '91 Vitus 979 and do not believe it has been impacted in any way.
https://cimg6.ibsrv.net/gimg/bikefor...ea0b3e44b.jpeg

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No it is more likely to soften over time as a frameset as I replied to Terrymorse above however subjected to plastic deformation to a desired shape it can become brittle but this would be very unusual in framebuilding.

So Strain Hardening/Work hardening are things?