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Lifespan of aluminium frames(14 posts)

Lifespan of aluminium framesalchemy
Sep 26, 2003 5:03 AM
My LBS said that an aluminium frame should be replaced after 4-5 years. Does this sound right and if so, why? I ride about 6,000km a year over pretty good roads - I realise a frame won't last forever but I would have thought I should get a bit more than 25 - 30,000km out of a good quality frame.
It depends......MR_GRUMPY
Sep 26, 2003 5:49 AM
on how heavy you are, how light the frame is, and how hard you plan to ride the bike.
If you are 200 pounds and have a 2 1/2 pound frame, and are a Cat 2 racer, the frame may last 1 1/2 years.
If you weigh 150 pounds and have a 3 1/2 pound Aluminum frame, and just ride easy centurys, the frame may last 10 years.
It depends......alchemy
Sep 26, 2003 6:00 AM
I weigh around 78kg and try to treat my bike carefully. The frame is made with Easton Ultralite so based on what you've said - maybe 5 to 8 years is a reasonable guess. Will there be any obvious signs when it's time to change ?
It depends......eddie m
Sep 26, 2003 7:03 AM
One problem with aluminum frames is that there is no obvious sign that the frame is near the end of its life. The best advice is to follow the manufacturer's recommendation on the life of the frame. Most commercial aluminum frames are built strong enough for a long fatigue life. I think that's what makes them "harsh." I suspect pro riders get aluminum frames that are lighter than what's available commercially, but they use them for at most one season before they toss them. The use of dangerously light frames may also be the reason UCI has required a minmum weight.
Actually, buying a new ultralight aluminum frame every year makes more sense to me than a titanium frame. It could be cheaper, and you never need to worry about your $4000 frame becoming obsolete when the rear wheel spacing increases for 12 speed.
'bout rightMR_GRUMPY
Sep 26, 2003 10:44 AM
Chainstay might crack. Rear wheel will rub other stay. Long walk home. Or if you get lucky, you'll be able to ride it home. Some older* steel frames can crack the same way. I have a friend whose downtube broke at the shifter bosses, during a race. That was back in the dark ages.

* 531 or SL
Inspect, inspect, inspect!Kerry Irons
Sep 26, 2003 5:19 PM
Look for paint cracks at the critical tube junctions. This is the best warning sign of frame failure.
Check the frames web sitebimini
Sep 26, 2003 7:12 AM
Depends on what the frame is designed for. The less aluminium used, the less the life. (i.e. the lighter the frame, the more you pay and the shorter the life). See what the vendor's web site recommends or see what the frame warranty is. On aluminium it is important to check for cracks.

Steel and Titanium don't have the fatigue issues of aluminium. A strong well designed steel frame can last forever with proper maintenance. I ride with several folks that have 10-30 year old steel frames.
re: Old Cannondale - problem?WryBiker
Sep 26, 2003 8:34 AM
I still ride a 1987 Cannondale RT 400 I bought new. Most of that time it has been relegated to training and charity rides and the occasional century and has probably averaged less than 1000 mi per year. It has never been used as a loaded tourer (but I weigh 200 lbs.) I check the frame visually every month or so and have never seen any problems, but based on this post, the possiblity of sudden unforeseen failure has me worried. Is my 15 year old frame with about 10k miles on it worn out and ready to be converted to wall art?
re: Old Cannondale - problem?Rusty Coggs
Sep 26, 2003 11:42 AM
Not likely in 10,000 miles.
ForeverDropped
Sep 26, 2003 9:21 AM
Unless the bike is stupid-light, poorly designed/built or is involved in a crash, an aluminum bike will last longer than your desire to ride it.

I have an aluminum frame that is going on 12 years old and has had the s#%t beaten out of it, including constant use in bad weather, racing, being chained to parking meters, being thrashed in the dirt. It is still going strong.
Forever is rightWryBiker
Sep 26, 2003 10:17 AM
Here is an interesting test report on the issue
http://www.efbe.de/etour109.htm
Forever is rightal0
Sep 26, 2003 2:13 PM
Really interesting and somewhat surprising results but ...

In real life frames suffers not only from cyclical loads (similated in this tests) but from occasional (and almost unavoidable) hits ant this may substancially affect lifespan for, especially carbon and to some extent to aluminium, frames

The second issue is that steel and titanium has some load treshold - they can stand infinite amount of loads under this treshold, aluminium such treshold is zero, so it would be at the end destroyed by even the lightest cyclical load and the higher load the faster.

To overcome (to some extent) this trait aluminium frames should be designed and produced very carefully (to evenly distribute load over the frame, to avoid stress raisers and so on), and manufacturers perfectly know it. So the "strange" results may be result of more caleful desining and production for aluminium.
Forever is rightlyleseven
Sep 27, 2003 11:09 AM
For whatever it is worth in terms of comparable products, extensive testing was performed on aluminum and carbon fiber baseball bats wherein they both were placed on an NCAA testing machine and subjected to baseballs being pitched, and the bats being swung at high speed. After repeated impact tests, the carbon fiber bats (kevlar reinforced) stool up significantly longer than the aluminum bats (Easton brand, if I recall). Aluminum due to its inherent nature, suffers micro denigration with repeated forceful impacts. It may take quite awhile for it to result in a structural failure, but eventually, it most certainly will. This is why, when you purchase aluminum baseball bats, including the most expensive ones, you are usually admonished to save them for game day and not use them regularly in the batting cages. Hopefully, those of you who swear by aluminum are not using them in a similar fashion as a baseball bat!!
Warranty issuesfiltersweep
Sep 27, 2003 10:13 AM
It does make me wonder, since Cannondale does not warranty against fatigue (but rather from manufacturer's defect)- does breaking at a weld or a bottle cage hole constitute defect?