Aluminum finite lifetime?

[BumbleBeeDave]

Posted this in the Strong spotlight thread, but also wondering what general audience knows/thinks about it . . . Several people have mentioned this issue to me.

I have a Specialized S-works E5 bike from 2003 and just got back from restoration my 1984 Vitus 979, of which I'm the original owner.

Is there any way to judge the "service life" of these frames? Does the service life have to do wih how much they've been ridden, or is it just the properties of the frame material itself?

Also does it have anything to do with corrosion or what conditions the bikes were ridden in? While I did ride my Vitus in the rain, I did the huge majority of riding in Oklahoma in summer months and out in northern California, again only in nice weather.

For we aluminum bike owners . . . do we need to worry about our frames cracking, or give them closer inspections once they are of a certain age? My Vitus will be my nostalgia and show bike. I'm not planning to ride it hard or long. But the S-works is a great riding, stiff frame that really gets up and goes when I stand on it. Do I seriously need to worry about it breaking under use at 9 years old?

BBD

[merckx]

I know someone who still rides his Cannondale that was purchased in 1984. It was the first road frame manufactured by C. However, I would be more suspect of a 1100g Columbus U2 frameset lasting that long. Every case and application is unique.

[AngryScientist]

i'm sure there are materials science guys who can chime in and explain more eloquently, but aluminum will eventually fail from small stress cycles. an area like your bottom bracket junction, for example are constantly loaded in tension, compression and vice versa, back and fourth, back and fourth as you pedal the bike.

so yes, under constant use, aluminum frames WILL eventually fail. the good news is that the numbe of cycles structural aluminum can take is in the millions. depending on just how many miles are on the bike, you're likely not near that limit. the thing is, its all based on relative stress and frame geometry. it would be very difficult to predict with any degree of certainty when or where a failure would occur. you dont hear of it very often with alu frames, that's for sure. the other good news is that any failure will likely begin with some cracking, we're not talking about explosive failure here.

for peace of mind, like with any other frame or material, it can crack, so keep an eye on it periodically, give it a once over when you clean the bike every now and then. other than that - dont worry about it.

IMO.

[William]

With aluminum it boils down to their lower fatigue limit compared to steel/Ti...It weakens over time through stress cycles.

An important structural limitation of aluminium alloys is their lower fatigue strength compared to steel. In controlled laboratory conditions, steels display a fatigue limit, which is the stress amplitude below which no failures occur - the metal does not continue to weaken with extended stress cycles. Aluminum alloys do not have this lower fatigue limit and will continue to weaken with continued stress cycles. Aluminium alloys are therefore sparsely used in parts that require high fatigue strength in the high cycle regime (more than 107 stress cycles).

You may never reach that breaking point in your lifetime....but it always a possibility.








William

[AngryScientist]

With aluminum it boils down to their lower fatigue limit compared to steel/Ti...It weakens over time through stress cycles.



You may never reach that breaking point in your lifetime....but it always a possibility.








William

Hey William - Just want to point out that the "107" cycles you're showing above is almost definitely supposed to read "10-to-the 7th", wherever you pulled that from.

107 would be scarey!

[jpw]

I had a Klein Quantum. It didn't crack, but the alu went powdery in several places over time. I don't like alu.

[William]

Hey William - Just want to point out that the "107" cycles you're showing above is almost definitely supposed to read "10-to-the 7th", wherever you pulled that from.

107 would be scarey!

That's too funny!!:)

I could have sworn it said that when I read it. 107 cycles, what's that? About 100 yards?:eek:





William

[nicrump]

funny thing about that vitus, i have seen em come un-glued, bent in a crash, dented to death and even folded but i have never seen one crack.

gosh. they are not welded are they?

[BumbleBeeDave]

. . featured aluminum tubes glues to the aluminum lugs. My understanding is that the whole thing was then stuck in an autoclave to polymerize the glue. Colors were anodized to the main tubes. So much for firefly's bold new trick with their frames . . . :rolleyes:

I hardly ever saw another on the road when I was riding it regularly--just saw another one once or twice in the 17 years from 84 to 2001 when I got my Serotta. I would run into people, though, who would tell me stories about their riding buddies whose frames broke riding off a low curb, came apart while descening at 35 mph, etc. Real confidence-inspiring stuff.

But when I started going on eBay I found they are pretty common there, both the 979 and the later 992. I also had no idea wen I bought the bike of Sean Kelly's success on them. Now I realize I've got a pretty cool bike.

BBD

[David Kirk]

I used to ride with a guy who owned a Vitus and he put well over 30,000 hard miles on it. He eventually retired it for something new but I'll bet it could be ridden another 30,000 without issue.

Dave

[nicrump]

they are very cool and completely rebuildable when they do come un-glued.

[BumbleBeeDave]

. . . very cool and completely rebuildable when they do come un-glued.

. . . I could say the same about me! :eek: ;)

BBD

[MattTuck]

Please ride that bike until it breaks. It would be a story for the grand kids.

"I rode that bike until it wore out underneath me, and I was thankful to have it last that long!"

Of course, your grand kids will probably have 3D printers and will ask "why didn't you just print out a new bike?"

[William]

Please ride that bike until it breaks. It would be a story for the grand kids.

"I rode that bike until it wore out underneath me, and I was thankful to have it last that long!"

Of course, your grand kids will probably have 3D printers and will ask "why didn't you just print out a new bike?"

Don't forget to add that you were barefoot and had to go up hill to and from school in the snow....AND YOU LIKED IT!!!;)




William

[esldude]

I have had an alu headtube develop a fatigue crack. I got it second hand and it was well used. I used it extensively. It was a Specialized Rockhopper. No crack or other problems visible. Then a tiny one appeared near the top front edge of the head tube the second year I had it. It began to grow slowly. I removed the steerer and found it went all the way through. So it became a parts bike. My guess is it got some very large stresses at times.

Aluminum will eventually fatigue even from the smallest repeated stress. The lower the stress the more repeated cycles of stress it takes. Steel won't ever fatigue below certain limits, but will above those limits.

[LO^OK]

Posted this in the Strong spotlight thread, but also wondering what general audience knows/thinks about it . . . Several people have mentioned this issue to me.

I have a Specialized S-works E5 bike from 2003 and just got back from restoration my 1984 Vitus 979, of which I'm the original owner.

Is there any way to judge the "service life" of these frames? Does the service life have to do wih how much they've been ridden, or is it just the properties of the frame material itself?

Also does it have anything to do with corrosion or what conditions the bikes were ridden in? While I did ride my Vitus in the rain, I did the huge majority of riding in Oklahoma in summer months and out in northern California, again only in nice weather.

For we aluminum bike owners . . . do we need to worry about our frames cracking, or give them closer inspections once they are of a certain age? My Vitus will be my nostalgia and show bike. I'm not planning to ride it hard or long. But the S-works is a great riding, stiff frame that really gets up and goes when I stand on it. Do I seriously need to worry about it breaking under use at 9 years old?

BBD

While I think no one could give definitive answers to these questions the following should be borne in mind. Aluminium corrode in a different, much more favourable way compared to steel. What's more, because the use of aluminium alloy I gather corrosion in "aluminium" bikes is not an issue (normally alloying improve upon the properties of the pure metals).

Another circumstantial evidence is the fact that many quality cars' suspension (not to mention cylinder heads and blocks), from the 1930s until today, make extensive use of aluminium alloys, which imply they ought to be pretty much fatigue and environmentally resistant (indeed, I am aware car components are engineered to higher standards). I see no reason why aluminium bikes, unless heavily/repeatedly crashed or defective, shouldn't last a lifetime.

[yoshirider]

how can you tell when an aluminum bike isn't as stiff as it was when new? i've only had 2 road bikes thus far. i bought a used 2006 aluminum bike and when i compare the ride to my carbon bike it feels vastly different. the carbon bike just lurches forward like 4.0L v6 car while the aluminum bike just accelerates slow like a 2.0L 4-cylinder car. can someone shed some light on this for me. thanks!

[bigreen505]

One local company says they expect a service life of about 10,000 miles from their Columbus Airplane frame before it starts to soften or crack and that it is best viewed as a single season race frame. One of my previous bikes was an Easton Ultralight frame with carbon seat stays. The carbon cracked, the aluminum is still fine. No idea of mileage on it, maybe 6,000 or so?

[thegunner]

One local company says they expect a service life of about 10,000 miles from their Columbus Airplane frame before it starts to soften or crack and that it is best viewed as a single season race frame. One of my previous bikes was an Easton Ultralight frame with carbon seat stays. The carbon cracked, the aluminum is still fine. No idea of mileage on it, maybe 6,000 or so?

can't share the name?

[binouye]

I've got an '83 Guercotti frame that (according to my quick internet research) was made by Vitus. It certainly looks just like the old Vitus frames, but different stickers. It has a crack in the upper head tube lug -- I don't know how it got the crack, but the components that were on the frame had very little use. I'm going to list the frame as "wall art" in case anyone wants it. Anyway, I thought it was interesting that the lug cracked without visible damage to the tubes or fork.

[Chance]

How many cycles/miles will a car's aluminum front suspension go through before the wheels just fall off, or how many revolutions will an aluminum engine head endure before the next fuel ignition causes it to explode like a bomb?:confused: Probably never?

If designed to last a while, just because it's made of aluminum doesn't mean it won't last. And there is no real way of knowing how a bike frame was designed, built, and even less how it was previously used. Predicting fatigue is a guess at best under these conditions.

[BumbleBeeDave]

http://guywires.com/vitusmain.htm

:)

I've got an '83 Guercotti frame that (according to my quick internet research) was made by Vitus. It certainly looks just like the old Vitus frames, but different stickers. It has a crack in the upper head tube lug -- I don't know how it got the crack, but the components that were on the frame had very little use. I'm going to list the frame as "wall art" in case anyone wants it. Anyway, I thought it was interesting that the lug cracked without visible damage to the tubes or fork.