How long should a bike frame last

[johnnyb47]

Hi,
Whilst out cycling today, if anything like me, you think of many random things.
As the miles slowly clicked by i got thinking how long my alloy Specialized Allez frame could potentially last before failing.
I seem to be averaging around 5000 miles a year along the road and it's now seen the best part of 17000 miles in total.
From my limited technical knowledge, i roughly understand aluminium has limited fatigue resistance compared to a steel frame bike, which will eventually end in the alloy bikes frame cracking.
Saying that though when i was a kid my two friends both had brand new bikes for Christmas. They were both identical steel framed racer bikes called Sun Solo and after around 7 months the light blue paint changed distinctly to a different shade were the cross bar met the head set tube within weeks of each other until one day, one of them developed a crack in the said place. They both got swiftly replaced by the manufacturer.
Back to my bike as an example, if i continue to use it as i am at the same level how long should i expect the frame to last before it eventually fails. It's a difficult question to answer, but there's got to be a given point as to when it would fail.

 

[fossyant]

If you look after it, a long time. 3 steel bikes around 30 years old and an alloy full sus thats about 5 years old.

 

[numbnuts]

My touring bike has done over 50,000 miles, but it's steel

 

[Drago]

It really is as Numbnuts suggests - a piece of string. Certainly a lot of alloy frames can feel 'dead' and uninteresting after a while, and the same with older alloy motorcycle frames (modern alloy perimiter beam frames are so rigid it doesn't really factor). But with so many innumerable variables involved its really impossible to say.

 

[johnnyb47]

Exactly, how long is a piece of string. I suppose you've got to factor in the general road conditions, riders weight and how aggressive that person is in there cycling style, but there's got to be some sort of general window as to when a frame would eventually fail mileage wise🤔 I'm kind of roughly hedging my bets it would be anything from around 50k to 70k on an alloy bike like mine..(I'll let you know in 100 years time 🤣🤣)

 

[chriswoody]

Exactly, how long is a piece of string.

Exactly twice the distance as from one end to the middle.

 

[HLaB]

Only bike Ive broke was my Scandium frame which lasted 25,000 miles but the Ti frame I've temporarily retired has done 40,000miles.

 

[johnnyb47]

That's interesting to read. What exactly broke on the frame. Did it happen due to normal wear and tare or was it abused or in an accident. 👍👍

 

[Venod]

Just seen this on Yorkshire Cycle Sales, do you think he caught something twixt tyre and frame ? he wants £30, worth it for forks etc.

 

[Shack]

Are you a sympathetic rider? Not afraid of a bit of maintenance and general TLC? I've got a Raleigh Granada I've had since new in 87 and still super comfy, but it's the running gear and wheel hubs that are feeling their age, the frame (although incredibly shabby paintwork) still rides well and runs true.

 

[SkipdiverJohn]

Most frame failures can be attributed to manufacturing or material defects, so are somewhat random in nature. Poor examples in any material tend to fail very prematurely, leaving the decently built examples to soldier on for years.
With Aluminium and Titanium frames, weld defects at fabrication are normally the root cause, as they are not tolerant of things like weld undercut or atmospheric contamination.
Steel tends to fail if clumsy use of cutting tools puts a stress-raiser into a tube during manufacture, which after repeated load cycles, can eventually cause a crack to propagate.
My 1991 Raleigh Pioneer frame failed at 28 years as a result of cracking at the point where the chainstays are slotted for the dropouts to be brazed in. The frame was scruffy when acquired and probably well abused. It's the only steel frame failure I have had.

 

[Drago]

Not to mention far too much exposed sestpost. The upbulb if the failures ive seen over the years are just forawrd of the top tube/seat tube junction, and all had a huge length of seatpost acting as a lever. The modern trend for more comoact frame sizes doesn't seem to have helped.

 

[cyberknight]

Not to mention far too much exposed sestpost. The upbulb if the failures ive seen over the years are just forawrd of the top tube/seat tube junction, and all had a huge length of seatpost acting as a lever. The modern trend for more comoact frame sizes doesn't seem to have helped.

indeed i have seen one and heard of a number of frames from one company that siffered that issue.My own alloy frames is 10 years old is still going strong apart from a repsray as the paint was tatty

 

[Moodyman]

Don't Specialised come with a lifetime warranty for the original purchaser? If so, the bike should outlast you.

 

[Drago]

indeed i have seen one and heard of a number of frames from one company that siffered that issue.My own alloy frames is 10 years old is still going strong apart from a repsray as the paint was tatty

Because im a fat lardy git muscled hunk I always fit 400 or 450mm sear posts to spread the load, except on old frames like my Claud that are larger and have less expost post.