Aluminium Frame - Life expectancy

Technically aluminum does fatigue, IBIS said this: "What we find is that aluminum (except for a couple of exceptions like the 5086 alloy) doesn't have an endurance limit. That means that even a minuscule load, if applied enough times, will eventually result in a fatigue failure."  HOWEVER IBIS also goes on to say this: "Kinda scary, don't you think? Steel and titanium are fine in this department, aluminum is not. Clearly, there are a lot of aluminum bikes out there. Are they all going to break? No, they're not."  And why won't they wear out? because over the years engineers have designed around the issue of fatigue, does that mean they'll never wear out?  I doubt that, all materials except for steel and titanium will fatigue at some point, it just means aluminium will get there before others, but how fast will that take you scream?  you probably have at least another 35 years left on the bike, so go buy your parts!

Personally I think steel will even wear out if someone rode the bejesus out of it over a 50 year span, not sure about titanium but I can't see why it wouldn't fatigue either given enough time and cycles; there is already evidence to show that CF fatigues and maybe faster then aluminium.  If you have ever seen an old car that looked like it was sagging in the rear, or the rear was lower then the front (not talking about lowriders), the steel leaf springs in the rear are fatiguing from the weight of the car pressing down and loading and unloading it's weight as it went down the road for all those years, so yes steel fatigues.

Metal fatigue needs to two things to occur.  A stress concentration and a fluctuating load.  The stress concentration can result from poor design or a defect in the structure - like a flaw in a weld.  The fatigue damage will occur faster if the peak of the fluctuating load is close to the failure load of the material.  As aluminium frames are nearly all welded and welds are a great source of defects and as aluminium has a lower yield stress than steel it is easier to get into that zone where the load cycles cause more damage.  

My Canyon frame failed at about 4 years old, a crack opened up in the top tube just in front of the seatpost, where there was a hole for the brake cable to fit inside the top tube. I bought a new frame - Cinelli Experience - for £275 and transferred all the parts over. The Cinelli is a better bike - more comfortable, just as stiff, just as sharp - and it has external cabling so fewer stress concentrations.

If you love your Cube Peleton, why not change the crank to a 52/36 or a compact 50/34? With a new crank, chain and cassette, new cables and new brake shoes, it'll feel like new.

I've only seen two frames failed mine and that of a lbs mechanic.  Mine was scandinium though which I believe is more brittle.  I'd go for it (the comment by Welsh boy is apt) what's the worst that could happen? In a couple of years it does fail and you need to transfer  your compact to a new frame.

My Cannondale alloy commuter frame (USA built) is 18 years old.  I've just upgraded over the years as bits wear out.  Just got the chainset replaced (Shimano SLX) and tailored it to the riding I do on it; I wouldn't have got that combination with a new bike.  My take is that I get components I want and if I tire of the frame, or it fails, I can transfer (most of) the components to a new frame.  A new bike is just a frame and a fit; a lot of the components are pretty cheap.  Older bikes also don't look as attractive parked in town, stations etc.

15 years is a long time. The problem with aluminium is that the any repeated load will cause it to fail at some point (no idea whether that will be 15 years or 150 years). This is because aluminium has no fatigue limit (https://en.wikipedia.org/wiki/Fatigue_limit) whereas steel and titanium frames  can last forever if the stresses are below the fatigue limit.

I've heard quotes of 5-10 year lifespans for aluminium frames, so I'd recommend that you get a new bike.

If there's nothing wrong with it after 15 years, I suspect it will be fine forever.

Welds will almost certainly be the first place where things go wrong, so check them visually.

I had a [brand redacted] frame that failed at a weld on the downtube (downtube was nearly completely severed when I finally noticed) and when I properly checked it over, the bottom bracket also had three other welds (downtube and both chainstays) that were very badly cracked. On a four year old bike!

I have had an alu frame give way around the chainstays where they were welded to the bottom bracket. Possibly due to a poor join on the wishbone/seatstay arrangement. But that is just 1 frame, so unless a whole load of others start chiming in with similar stories I would say go for it in terms of replacing parts now. Some frames actually aren't that expensive new e.g. Dolan Prefissio is £69 at the moment, so if it was to give up the ghost in a year or two, buy another with the same or similar geometry and swap over the bits.

I did similar. Different alloy frame. Hoping the combination lasts and saving towards a future frame/wheels while with hope.
Cube peloton reads more of a racy frame, 1 of the wrecks used to part was a racy 2014 alloy frame; her head stem had cracked.
Best luck

I have seen enough evidence to suggest that aluminium frames last so if it fits and is comfortable then put a new group set on it and give it a second lease of life. However, if you are looking for an excuse to buy a new bike then go for it, in the words of Pink Floyd “life is a short warm moment and death is a long cold rest “.