Lifespan of an aluminium frame

rjeffroy

I have an early 2004 alu race bike (Merckx TeamSC) with about 10000 miles on the clock. It has had a fairly hard life being regularly raced, also used for training, a couple of etapes, tour of flanders sportive and the odd commute.

I am starting to wonder if I am getting anywhere near the fatigue limits for the frame. It's a great bike and I don't particularly want to replace if I don't have to.

Perhaps I should be worrying more about the carbon forks? (Every other component has been replaced)

Monty Dog

10,000 milesless than a year's riding for a pro - so you're probably just getting past the breaking-in stage! Merckx bikes have a reputation for being stoutly build for Belgian roads, so given your type of riding, I doubt you've got any problems. My main worries would be if you've crashed the frame or if you are particularly heavy, a powerful sprinter or have a history of breaking bikes. You could always contact the Merckx factory for a repain and they could inspect it for you whilst it's been stripped-down - it'll come back just like new. Again, forks shouldn't be a problem either if you haven't crashed - I have some 8 year carbon forks on my Colnago and they've taken at least twice your level of use and I've no concerns.

mookie

I think I've raced against you on that frame (in Sept 2004...).

The type of alu might have some bearing. I wouldn't trust an SC61 frame for more than a couple of years or so (or a U2 for a year) but tougher things like Deda 7003 should last longer. The 'SC' in yours might refer to scandium, in which case it's a bit on the fragile side....

I've had a Sigma 7003 alu frame as a hack since 2004, which replaced a similar frame which cracked at the head tube after three year's racing. Noawadays I just keep a careful eye out for cracks and nicks when cleaning it - especially around the tube joints (BB, head tube, dropouts, especially).

Mookie

meanwhile

Look at http://www.63xc.com/scotn/alumin.htm. This is a bike metallurgy guide by someone who knows what he's talking about - he founded the cult US MTB maker, Isis. The basic answer is that an alu bike that's designed to be robust and long lasting will be, just as much as a steel one. An alu bike that doesn't last has either been mis-designed - which is equally likely with steel - or has been designed to make performance an absolute priority; eg look at the advice from a Kona representative re their cyclocross frames here -

http://www.konaworld.com/owners%5Farea/ ... major+jake

- which comes down to "Our lightest frame, cut down to the last gram frame, is meant for races only - because it shaving those fast few grams mean that it will burn out fast. Use the slightly heavier frame for training, especially if you're a big guy." Which camp you and your bike will fall into depends on the intention of the bike designer, not the frame material.

meagain

FOUR years? 10THOUSAND miles? Aluminium? Carbon? NOT (t)rusty steel? Amazed it's lasted this long. :shock: :roll:

Take a tenner?

Lysander

I have a 6 year old SC61.10A Ciocc does that mean I should be thinking about chucking it? I weigh just under 12 stone.

notsoracy rich

I have a Merckx team Scandium which I bought second hand about 6 years ago,which I still race on. The original Merckx forks came loose at the join between (carbon) steering column and (alloy) crown.- I replaced them with Easton EC90 SL full carbon forks. However this is the frame that Van Petergem won Paris Roubaix on, so its tough enough. My frame wasn't used by Van Petergem-he's a lot bigger, but was used by Simon Day,an ex professional.
Merckx Scandium frames were made from Easton scandium which has a good reputation for reliability, although I have heard stories of Scandium frames made by Deda which had a reputation for cracking.
Anyway, its a brilliant frame, and yours still has years of life left, so enjoy!

Rich.

JWSurrey

A bit off topic, but we have a 10 year old Aluminium framed fully rigid MTB (one of the first mass market aluminium bike frames - at the time we also bought a steel framed MTB).... Still going nicely, after 2 bottom bracket replacements!

mookie

It all depends what happens to the frame. I don't pretend to be a metallurgist, but the problem is usually that a tiny crack or nick can build into something much more serious pretty quickly because the material has little or no elasticity. The chances of such small nicks developing (or being generated via crashes, stones, etc) just increase the longer and harder the frame is ridden.

Not to say that if a light alu frame is ridden smoothly it can't last a long time. The real problem tends to be the ultra light scandium frames that were around in the late 90s and earliy noughties (like my Casati m:U2), which were so thinly-walled that you were lucky if they got you through a season; especially if you were a big powerhouse. My impression is that the generation that came afterwards, however, were better in this respect.

andrewgturnbull

mookie wrote:

It all depends what happens to the frame. I don't pretend to be a metallurgist, but the problem is usually that a tiny crack or nick can build into something much more serious pretty quickly because the material has little or no elasticity. The chances of such small nicks developing (or being generated via crashes, stones, etc) just increase the longer and harder the frame is ridden.

Hi there.

I don't that what the poster was worried about. The fact is that if you continually stress aluminium beyond a certain tension then it will suffer from fatigue and fail (i.e. crack). If however the frame is designed so that the stresses on any single component part never exceed this critical tension then it will pretty much last forever.

This is why aeroplanes have round windows.

My guess is that if your bike has done 10k miles with no probs then the design is sound and you're onto a winner

Cheers, Andy

aracer

It's a little more complicated than that, Andy. The reason alu frames are supposed to be a problem is that alu (unlike steel and ti) doesn't have such a fatigue limit - any stress at all, however low will eventually cause it to fatigue if repeated enough times. This does mean that any alu frame will eventually break, and the lightest ones may only have a few seasons in them. However anything apart from an ultralight one will likely last a normal lifetime if properly designed.

Planes have round windows as the corners of square ones act as stress concentrators - something which unfortunately nobody realised when building the original Comet.

paulcuthbert

I've got a Trek 1.1 frame that I've ridden all year round in all conditions and over loads of different terrain. According to my log I've done over 20,000 miles on it since August 2010 (probably more since I forget to log for long periods!)

Noticed what looks like a split in the drive side chainstay the other day. Was wondering if it'd be worthwhile having this repaired, or would I be better off with a new frame? I've read other places that a well used Aluminium frame will last 4-6 years tops...

k-dog

Lifetime guarantee on those Treks so if you're the original owner that's where I'd start.

keef66

I have the original Kinesis Racelight Tk coming up for 8 years old and ridden year round. It claims to be made of some mythical alloy Kinesium, and the downtube sounds very thin walled. I give it a proper wash ever 6 months or so, and give it a good looking at for any signs of corrosion or cracking. So far so good.

Son had an alloy FS Saracen MTB which appeared to be built like a tank (certainly weighed as much) but after 5 years of paper rounds and the occasional off road excursion it developed a crack at the bottom of the head tube.

I'm thinking quality of alloy is probably more important than quantity...

pippi_langsamer-2

I'm still riding around (in the Winter), on a 21 year old Dolan 7005 and there's no signs of it giving up :shock:

I had the frame stripped professionally years ago and resprayed, and the bare alu tubes/ welds etc were all perfick...to the naked eye

ForumNewbie

I don't know about aluminium frames, but there's a long lifespan on this thread - resurrected after 7 years

paulcuthbert

k-dog wrote:

Lifetime guarantee on those Treks so if you're the original owner that's where I'd start.

Hi. Yeah, good advice. I'd remembered about that subsequent to posting. Luckily I am the original owner and still use the shop I bought it from frequently. They've been the only shop to service it, so they know it well!

taon24

I have on reasonable authority that all material has elastic and plastic deformation limits. Aluminium deforms plastically until you apply 90 MPa, while alloys of aluminium can get up to 400 MPa. Steel deforms plastically at more like 600 MPa.
Further Aluminium is used in some mountain bike frames. These will almost certainly take greater peak pressures than a road frame and therefore in reality your aluminium road frame should last almost indefinitely if it isn't too badly abused (crashed, hit, etc)

keezx

It's all a matter of design and dimensions.
A heavy aluminium frame will last very long, while a very light one will probably not.