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Fatigue life for an aluminum frame? (m)(8 posts)

Fatigue life for an aluminum frame? (m)BoneDigger
May 11, 2001 3:32 PM
I have a 1998 Cannondale R300 (CAD2) with RSX 7 speed components. The frame was ridden very little for the last couple of years and is now just starting to get its share of riding. I am considering upgrading to a carbon fork (to take the edge off) and maybe 105 9 speed components. MY question, is it worth upgrading or would I be better off waiting and buying a new bike with 105 around Christmas (when I can afford it). I need a new mountain frame as well and really would have to chose between the two if I go with a new bike. With a component upgrade I can probably do both. How long can an aluminum frame stand up to use (I'm not a road racer but will spend 7-8 hours a week on the bike training and an occassional tour)? I appreciate any input.

Todd
re: Fatigue life for an aluminum frame? (m)Akirasho
May 11, 2001 5:16 PM
A carbon fiber fork will indeed (in general) take the edge off road buzz on your CAAD2...

RSX is a capable component set (I still have a CAAD3 equipped with RSX/RX100 gruppo). An upgrade may not be necessary (at this point) depending on your gearing needs. The group is heavier and not as aesthetically refined as 105... but this barely affects overall performance for most enthusiast riders.

While I like Cannondales, I wouldn't put too much into upgrading a CAAD2, especially since CAAD3's have come down in price. A fork upgrade would make the CAAD2 a very nice second bike, otherwise, you might wanna investigate a CAAD3 or above.

Deciding between bikes (MTB or new road) is the bane of us all... good luck!

Your CAAD2 could last a lifetime... it's hard to say (lots of variables). While aluminium as a frame material does have fatigue limits... Cannondale "overbuilds" their frames to give them relatively long life (Cannondale used to warrant the frame for life). A Pro or CAT racer might wear one out (I know of a trackie that's been using a 'Dale track frame for 6 years... lots of stresses in that discipline)... but most folks could look forward to years of good service from any quality built aluminium frame.

Be the bike.
probably practically forevergeezer
May 11, 2001 5:35 PM
Don't listen to all that bunk out there about limited life spans of AL frames. A poorly made frame might break while a well-made frame should last as long as you are interested in it, regardless of material. Cannondales are very tough and well-made frames and fatigue probably won't be an issue for you. If it does break, brag about it and buy another one.
a lonnnnnng time.Largo
May 11, 2001 7:54 PM
Look at aeroplanes, Boeing 737s have been around forever.
A good Alu frame should last for years, unless it is a super light model, in which case, you pay for light weight, one way or the other.
a lonnnnnng time.LC
May 11, 2001 8:49 PM
CAAD2 has a lifetime warranty, and will probally last longer than you will want it to. I am pretty heavy and ride very hard and have 22,000 miles on the same frame and it just won't break!
a lonnnnnng time.Skip
May 11, 2001 10:51 PM
True; but, all have regular 100 hour and annual inspections. Any non-structural cracks are stop-drilled, and panels, skins, and worn out or cracked structural components get replaced as needed.
Depends on who you ask.shmoo
May 11, 2001 9:52 PM
Many steel/carbon/Ti riders will include fatigue life in their long list of reasons why aluminum is an inferior (or at least undesirable) frame material. However, I believe these claims are largely based on outdated and erroneous information, stemming from rumor, hear say, prejudice, tradition, and/or just plain brainwashing. I have heard builders and engineers explain the theories relative to fatigue in the different materials, but anybody who actually rides aluminum will tell you it's no more subject to failure in the real world than any other material. In fact, posters of these forums have reported more actual (as in first hand) failures in carbon and Ti. I've heard a lot of people advise that aluminum WILL crack or WILL fail or WILL beat you up, but through all the banter, I don't recall one poster who actually reporting a contemporary aluminum frame failure. I recall reading about a C40 failure, Litespeed bottom bracket failures, numerous OCLV problems, but no aluminum or steel failures. (Not that they haven't happened - only that I don't recall seeing them here, or on other forums). I'm not saying that aluminum is better or worse than any other material. (Actually it's more a matter of design anyway). I'm just saying the hype is hype. Don't believe it.
re: Fatigue life for an aluminum frame? (m)Jz
May 12, 2001 7:06 PM
I broke my Voodoo Bokor MTB frame (Easton Ultralite Alum), but I obviously wasn't partaking in roadbiking activities. I might be crazy, but it doesn't seem like there is much you can do to break a roadbike frame (made out of a non 'exotic' material). Even a spill at high speed probably wouldn't produce the stress of an average mtb day in most cases. I realize road bikes are meant to be lighter and less bulky, but they are still built solid enough I would surprised to see one break. Shrug, just me...