My old Peugeot failed at exactly the same spot after about 7k miles of my ownership. At the time I put it down to me being heavy and mistreating it but I've seen a couple of steel frames fail the same way and now think that there was probably a stress riser at the bridge which caused it.
How long should a bike frame last
- Thread starter johnnyb47
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My old Peugeot failed at exactly the same spot after about 7k miles of my ownership. At the time I put it down to me being heavy and mistreating it but I've seen a couple of steel frames fail the same way and now think that there was probably a stress riser at the bridge which caused it.
Johnno260
Veteran
- Location
- East Sussex
I have seen this frame thing discussed before and it always causes dis-agreements.
Thing is sure Alum has a shelf life with fatigue, but some of that depends on the rider and conditions, if you hit every pothole and have the seat stem on the limits you for sure are going to stress things out.
With mine it’s Alum sure at some point I will look to change the frame but I like the bike it’s comfortable and it makes me smile, I don’t give a rats that it’s a 2016 bike, doesn’t mean I will abuse it though, I could replace it but I fall into the category of people that look after things and try and make them last as long as possible, the bikes always wiped down if it needs it and the drive train is kept clean and lubed, one of my main routes has a shared ped/cycle path that undulates a lot as it has entrances for fields and drive ways, anything like that I come off the saddle so I don’t transfer all my weight through the frame, and I can flex my knees to take some stress out.
Also as has been said before cost is subjective.
If you want a really good metal fatigue analysis get YellowSaddle on here, he knows his stuff.
Thing is sure Alum has a shelf life with fatigue, but some of that depends on the rider and conditions, if you hit every pothole and have the seat stem on the limits you for sure are going to stress things out.
With mine it’s Alum sure at some point I will look to change the frame but I like the bike it’s comfortable and it makes me smile, I don’t give a rats that it’s a 2016 bike, doesn’t mean I will abuse it though, I could replace it but I fall into the category of people that look after things and try and make them last as long as possible, the bikes always wiped down if it needs it and the drive train is kept clean and lubed, one of my main routes has a shared ped/cycle path that undulates a lot as it has entrances for fields and drive ways, anything like that I come off the saddle so I don’t transfer all my weight through the frame, and I can flex my knees to take some stress out.
Also as has been said before cost is subjective.
If you want a really good metal fatigue analysis get YellowSaddle on here, he knows his stuff.
BrumJim
Forum Stalwart (won't take the hint and leave...)
- Location
- Selly Oak, Birmingham
Indeed. Have a good look at BS7608 or the TWI book "Fatigue Design for Welded Structures", but sadly you will need to pay for them. Welding introduces stresses in the parent metal as well as the weld itself which turn a material with an infinite fatigue life into one with a finite one. So expect a fatigue crack to start either in a weld or at the weld toe.
In my industry we tend to regard anyting over 10^7 cycles as practically infinte, but if you have the equipment, funds and patience, it will crack under any stress.
- Location
- London
i've got one broken down (ie bits taken off) in my garage.
ally, welded in the USA I'm pretty sure.
welds are beautiful and put more modern welded "pie crust" ally to shame.
But I've gone off ally.
and dale's weakness was all too often some non standard interfaces between frame and bits.
So I am putting my faith in stuff to outlive me in good old fashioned Ridgeback quality steel.
I have 3 90s ones.
The 4th one has only been retired after a rack mount broke off but the frame is still fine and I could always have doubled up the frame/guard mounts.
edit - remembered I have a near mint 5th one but have decided that the size isn't me - must sell.
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- Location
- London
you talking about you or the things between your legs?
Drago
Legendary Member
- Location
- Suburban Poshshire
They do, yes. However, a properly designed, cosntructed and utilised frame could conceivably be used for centuries and never be stressed beyond its limits. It's not an inevitability.
Of the 4 common materials, only aluminium has flex memory and over time fails due to metal fatigue. No amount of wiping will help, it the nature of material. The only way to stop fatigue is not to use it or use it sparingly. It is however great while it last and best value for money and affordable.
Agree on the Yellow saddle though.
Ming the Merciless
There is no mercy
- Location
- Inside my skull
Red frames rust faster
Steel bikes if well constructed and maintained to stop rust will last a lifetime. Hence it is popular for custom build and popular with uni students who can only afford second hand and then sell it on when they complete their studies.
Johnno260
Veteran
- Location
- East Sussex
haha I wasn't suggesting cleaning it helps, just meant it in terms of looking after something in this case the paint.
Like you said sooner or later it will fail, but you can take steps is all I meant, smashing into potholes etc and having the seat stem to the max won't help was all I was trying to say from a fatigue pov.
And like you said it's great value for money.
I have seen CF take a what I would call a light hit in the wrong place and fail.
My next bike I would like to last me a few years next time I feel a replacement is due, I have been looking at Reilly Ti frames from Brighton.
Ming the Merciless
There is no mercy
- Location
- Inside my skull
After 26 years, sold my steel bike I got for my 18th birthday. The frame was absolutely fine as were original wheels and drive train etc. It was before I took up long distance cycling so was mainly used for the daily commute and the odd trip out for 1.5 hours or so.
There is no looking after an aluminium frame unlike a steel frame. The nature of the material causes flex and hence metal fatigue as long as you use it
No argument on CF, it cannot handle impact. It is the lightest material and used for competition and fitness training.
Ti is the best, hence life time warranty for frames from manufacturers. As bike geometry is more or less the same for a human being and Ti does not need paint work it will look good and you only upgrade the groupset. Its a keeper. Hence very little on the second hand market.
Johnno260
Veteran
- Location
- East Sussex
CF I have no desire to own, it's overkill for my requirements.
Ti I would like and to be honest when I want/need to replace my current bike I will have a good look at Reillys show room.
- Location
- London
Possible some may decide they like cycling around and keep them?
Personally I prefer second-hand steel over new ally.
- Location
- London
Go into hiding now before the bike industry takes out a contract on you.
(not getting at you)
