Worn out steel frames

[iandg]

Although I said above that my Mercian felt the same after 35 years, I did notice quite a significant drop in speed. About 5 minutes over 25 miles.

I'm still riding my 1977 Raleigh Professional. I have also noticed it doesn't go as fast as it used to back in the day

 

[Blue Hills]

I'm still riding my 1977 Raleigh Professional. I have also noticed it doesn't go as fast as it used to back in the day

new steel limbs needed.

 

[Vantage]

Mine needs new pistons and the air pressure pump is suffocating these days too.

 

[Bonefish Blues]

Have no reason to think there's a problem with non rusted steel bike frames but your comment is a bit of a generalisation. Ever heard of the Comet plane?

Wasn't it the case that the Comet utilised aluminium, which is indeed much more prone to fatigue/material change than good ole' steel, which is hugely resistant to same. They also designed certain elements like the windows without an understanding of the qualities of same, creating stress points. I'm (obviously!) no metallurgist, but that's my layman's understanding.

 

[12boy]

What would you count as heavy use?

30 K miles or less perhaps with curb jumping or riding on really rough stuff.

 

[12boy]

To echo Reiver, how exactly does a head tube accordion?

I've seen them bent out of position after a crash, but compressing and decompressing like an accordion??

This one developed horizontal waves or ridges. The rest of the bike seemed straight.

 

[12boy]

Where did you hear this?

I have heard this from the guy who runs Turin Bicycles in Denver, where I bought the Witcomb in the early 70s. I think I've encountered this opinion elsewhere but can't put my finger on where.

 

[Pumpkin the robot]

Many years ago when I was doing my apprenticeship in toolmaking, we learnt about creep in materials. (one of the few things that I have managed to vaguely reember)
Put basically it means that a material put under high stress over long periods can deform and actually grow. I just did a quick check (it was over thirty years ago I was taught about this) and it would apply to steel and you do not need to take the material past it's yield strength. It gets worse with heat (not really an issue with bike frames) but heat only accelerates the process.
Compairing bike parts with aircraft stuff is pointless. Aircraft stuff has a shelf life, they know when it will fail, and also why. Therefore they only use parts for a certain amount of time with a huge built in safety factor.

 

[Rusty Nails]

I've never come across this particular issue, nor have I heard of it in the 50 years I've been riding and working on bikes. But if there are horizontal ridges in the head tube then I would not like to trust it

A photo of the head tube would be interesting.

 

[classic33]

Wasn't it the case that the Comet utilised aluminium, which is indeed much more prone to fatigue/material change than good ole' steel, which is hugely resistant to same. They also designed certain elements like the windows without an understanding of the qualities of same, creating stress points. I'm (obviously!) no metallurgist, but that's my layman's understanding.

The shape of the windows was the weak point on the Comets.

 

[classic33]

This one developed horizontal waves or ridges. The rest of the bike seemed straight.

I'd leave it, or at best restore as a show piece.

 

[Tigerbiten]

This one developed horizontal waves or ridges. The rest of the bike seemed straight.

I've seen that happen on the cross frames on my recumbent trike due to a bad batch of frame that hadn't been properly heat treated after the tubes had been bent.
It's a bit like how cracks are going to form due to a defect in the material exacerbated by heavy use, not by heavy use alone.

 

[Blue Hills]

Wasn't it the case that the Comet utilised aluminium, which is indeed much more prone to fatigue/material change than good ole' steel, which is hugely resistant to same. They also designed certain elements like the windows without an understanding of the qualities of same, creating stress points. I'm (obviously!) no metallurgist, but that's my layman's understanding.

Yes it was fatigue. Fossyant said "metals"- hence my comment about generalisations. You are also correct about the windows issue.

 

[Smokin Joe]

It was regularly said when I started cycling that steel frames lost their liveliness after a period of use. Bernard Hinault was quoted as saying that when the team were issued new bikes before the Tour de France everyone used to comment on how much livelier the new frames felt. I've no idea whether their is any science behind the theory, but given the amount of time pro riders spend on their bikes they must be far more sensitive than the rest of us to small changes in performance.

 

[12boy]

This frame is in my bicycle storage across town, along with another bunch of bikes, but the rent is due so if the bikepath isn't icy tomorrow or Monday I will pay rent and get a photo. BTW, I have heard of retempering springs by reheating them but I would think the brazing would go before they get hot enough. If in fact they do deaden with time and use it would be very nice to restore them to their original liveliness.