ALU- Frames - How long...

[Flying_Monkey]

If nothing goes wrong, aluminium will last longer than steel as it won't corrode to the same extent. However aluminium is also more prone to sudden failure and you won't get any warning if it does go. It is worth adding that steel can be repaired by any blacksmith, so it would make more sense if you were touring in a remote and undeveloped area. This isn't most of us however...

 

[dantheman]

Aluminium should last just as long as steel if looked after, maybe even longer. its slightly softer, and needs special welding/brazing, but can be repaired, Ive worked in metal workshops and there are paople who will repair them, after all, why do you think scaffolding is almost always aluminium?- (no corrosion) and have known scaffolders to come in and have them repaired- and these have to be inspected by law, so if they can be repaired- why not a bike frame..

 

[Smokin Joe]

It used to always be said that steel tubing went "Off" and lost it's qualities after a period of hard use. The theory has been rubbished by many people in recent years, but interestingly Bernard Hinault repeated this in an interview in the May edition of Cyclesport. He claimed that when they were issued with new bikes for the TdF the frames felt stiffer and livelier than the identical models they replaced.

No views on this myself, but it used to be a fairly common opinion among the pros and top amateurs.

 

[fossyant]

Just an excuse to get a new bike.

I see no reason why a looked after bike won't last years, what ever the material. I, myself, am very interested in 953 !

Steel does suffer corrosion, but if you are careful, and when new spray the inside of the tubes with a wax oil/rust preventer, then it will last. Corrosion on alloy is just cosmetic, but doesn't half look horrible.

Any frame can be re-painted, ideally by folk qualified to do it !

 

[gbb]

A lot of talk about a frame looked after should last years...i'm not so sure.

Now you (or i anyway) realise the variables that affect a frame...not least the probable fact that a weld may or may not be 100% during manufacture.

My Via Nirone is circa 4 years old, done around 4000 miles. I am relatively light at 10.5 stone, dont race and dont abuse my bike. I dont wrap it in cotton wool either.
I do like to get out of the seat and honk up hills...this no doubt subjects the frame to a lot of stress...probably the highest stress its likely to see.

Mines failed quite spectactularly considering i consider i dont abuse my bike.

Therefore....looking after a frame is a bit like having a Ferrari...and driving it at 30 mph.

I suspect the weld on mine was never 100%. If i've abused my bike, 1/2 the frames ever made would have failed as well.


I consider it a one off failure. It wont stop me having another Bianchi. I love it.

 

[fossyant]

By looking after -I mean checking for damage, touching up chips (cosmetic for carbon, but stops corrosion for alu and steel. If it's going to crack, then there isn't much more you can do.

My 3 bikes are steel though - aged from 18 years old (Herety) to 12 years old Ribble. All have been ridden hard, the Herety raced for 10 years.

My training bike (currently a Ribble 653) is on it's 3rd frame (531c then a 653) - two previous frames were dispatched to the great junk yard after interactions with vehicles !

 

[gbb]

By looking after -I mean checking for damage, touching up chips (cosmetic for carbon, but stops corrosion for alu and steel. If it's going to crack, then there isn't much more you can do.

My 3 bikes are steel though - aged from 18 years old (Herety) to 12 years old Ribble. All have been ridden hard, the Herety raced for 10 years.

My training bike (currently a Ribble 653) is on it's 3rd frame (531c then a 653) - two previous frames were dispatched to the great junk yard after interactions with vehicles !

Ah, now i see what you mean fossy
Been out on the 531 myself tonight. It occurs to me its perhaps a better ride. Therefore, what do you get from an ally frame. Aesthetics perhaps, but not much else.

 

[Smokin Joe]

A lighter bike is what you get.

Which is the principle reason allu and now carbon have displaced steel.

 

[Milo]

My mates steele bataglyn sp? bike weighs less than my ALu frame granted mines is just a dawes giro.

 

[skwerl]

A lighter bike is what you get.

...for the price is what I'd say. It's possible to make light steel frames (ie with Reynolds 953, Dedacciai 16.5 etc) but they cost considerably more than something of similar weight in Alu.

 

[User482]

Actually, Alu does have a finite fatigue life whereas steel doesn't. That said, given the tiny numbers who keep their bikes long enough to be an issue, I doubt it's worth worrying about.

 

[twowheelsgood]

I wouldn't worry about fatigue stress.

Aluminium gained a bad reputation because of design and quality issues early on.

Early frames were built in a similar manner to traditional steel, albeit luggless. This type of tubing in Al isn't ideal, which is why a modern bike will most likely use "oversized tubing". These frames were often built too light and were badly welded. Welding Al is much more difficult than steel. The only truly satisfactory way of welding a frame is robotically. Early alloys too could also be pourous and much weaker than they could have been.

 

[asterix]

The main difference between the alloys is metal fatigue. Both suffer from it but aluminium does so at any level of stress whereas steel is affected only beyond an ascertainable stress level that is unlikely to reached by a bicycle frame in normal conditions. Airframes are not a good guide to bicycle longevity as these are rigorously inspected and can be repaired if necessary. And they have a limited service life.

As far as comparative frame weights are concerned, I believe that for most of us, improving rider fitness is of vastly more importance (and far cheaper) than the minor difference that can be achieved by using one or other alloy, etc. Naturally this theory doesn't help to sell expensive bicycles

 

[Smokin Joe]

As far as comparative frame weights are concerned, I believe that for most of us, improving rider fitness is of vastly more importance (and far cheaper) than the minor difference that can be achieved by using one or other alloy, etc. Naturally this theory doesn't help to sell expensive bicycles

How does buying a lighter frame prevent you from improving your fitness?

 

[Mr Pig]

The main difference between the alloys is metal fatigue. Both suffer from it but aluminium does so at any level of stress whereas steel is affected only beyond an ascertainable stress level that is unlikely to reached by a bicycle frame in normal conditions. Airframes are not a good guide to bicycle longevity as these are rigorously inspected and can be repaired if necessary. And they have a limited service life.

Great reply. Basically a steel frame will last a lot longer, provided the frame isn't abused or damaged where as an aluminium frame will deteriorate and become more likely to crack even under normal use. I've heard people say that they wouldn't use an aluminium frame that was more than five years old. I don't know about that myself, seems rather conservative but I'm not an expert.

Another very important thing to remember is that cracks/failures in something like a bike frame will very often be caused by and spread from an area of damage or corrosion on the surface. Unprotected aluminium corrodes pretty happily in our nice British weather so a scratch or damage can let corrosion form a weak spot on the metal which can lead to a total failure. In the right place an area of corrosion will reduce the strength of a piece of metal by 50% !!