Can you ride your retro bike forever?

[hamster]

For steel frames the fatigue life is pretty much infinite provided there aren't stress raisers in the frame. This is fundamentally different to Alu, although if well engineered (Zaskar ) it's as close to infinite as makes no difference.

And no, the frame isn't getting softer, it's just that Alu bikes are built stiff to give them acceptable fatigue life, so we are all used to hyper-stiff frames these days.

Whether a very stiff frame is a good thing is a separate discussion. Bike brands promoted this as an advantage, whereas it was more of a consequence of the move to Alu (which is cheaper to fabricate than steel) than a specific design objective.

 

[JamesM]

Steel as a material has a limit which provided the forces/stresses don't exceed fatigue does not occur, above that limit and steel fatigues. The same is true of titanium but not aluminium. Aluminium fatigues under any amount of stress no matter how small. So all alumium frames will eventually fail due to fatigue, when just depends on design and use. Steel and ti frames may or may not suffer from a fatigue failure, again depending on design and use. Steel rusts though :roll:

 

[highlandsflyer]

I would hesitate to punish an older Alu frame I did not know the history of, as I would a Carbon composite one.

Steel is all about the original consistency, design, fabrication method and how it has been looked after.

Even 'cheap' steel can be made to do the job long term compared to Alu and other materials.

My favourite designs tend to be steel where it really counts, and something lighter where there is less stress. That combination gives near the lightness of Ti without the expense and difficulty of repair.

 

[legrandefromage]

its an old argument about aluminium frames but as theres even older aircraft in the sky, I'm not going to worry.

 

[JamesM]

As I said your frame will eventually fail due to fatigue. But that could be 100 years or 100,000 miles from now. A steel frame that is pushed over its limit due to poor design or heavy use could fail earlier, or just rust away. A steel frame that has rusted internally may now as a result be operating above the materials fatigue limit. Who knows, just keep riding em until they break!!!

 

[highlandsflyer]

I mean downhill or other extreme use. for example, not bimbling about or general trail use.

I ride old Alu quite happily as a rule, but prefer to shove new forks, bars and seatposts on them.

If you want to go touring I suggest getting a newish quality bike, or a quality steel retro.

If you apply the rigorous inspection routine older aeroplanes undergo, including stripping out sections to inspect internally, X Raying and stress testing, etc. then you are on a winning formula for using any kind of old metal.

Thorough inspection of your bikes, especially around the joins, makes a lot of sense. Even new frames are known to fail, and if you can spot signs before it happens you could save yourself a face full of earth, or rock.

 

[JamesM]

My brothers 2008 Trek Fuel EX8 broke a rear seat stay after not many hours of typical not overly heavy use. A google search indicated it was a common failure for the early ones. The break occured near, but not at the end, of the stay, right where the disc brake mount was welded on. The weld had cause a stress riser. The later bikes (and the replacement part fitted to my brothers bike under warranty) meerly had a tapered smoothed out weld to spread the load better.

 

[sinnerman]

As I said your frame will eventually fail due to fatigue. But that could be 100 years or 100,000 miles from now. A steel frame that is pushed over its limit due to poor design or heavy use could fail earlier, or just rust away. A steel frame that has rusted internally may now as a result be operating above the materials fatigue limit. Who knows, just keep riding em until they break!!!

and then repair it and have another go ...............................

 

[John74]

Steel as a material has a limit which provided the forces/stresses don't exceed fatigue does not occur, above that limit and steel fatigues. The same is true of titanium but not aluminium. Aluminium fatigues under any amount of stress no matter how small. So all alumium frames will eventually fail due to fatigue, when just depends on design and use. Steel and ti frames may or may not suffer from a fatigue failure, again depending on design and use. Steel rusts though :roll:

Sounds good...

Great now I have to worry about my 1980s Alu bikes ahahaha!!!!

Thing is that the weather is getting worst (wet) and I 'have' to use my old alu bikes...sigh

Hahaha