|Aluminum Frame Durability||Mapei Boy|
Sep 17, 2001 1:36 PM
|I own a Colnago Dream Plus. It's solid, lovely and wonderful, but I do have a question. How long (in miles or years) do aluminum road frames usually last? How do you know when the frame is approaching the end of its useful service life? Does it creak? Does it get wobbly? Does it fail catastrophically? Do cracks appear?|
|No possible answer to this question||Kerry Irons|
Sep 17, 2001 4:35 PM
|The durability of any frame is a combination of the material, the fabrication, and the use. A 250 lb masher who never dodges potholes on a poorly designed and poorly welded superlight Al frame might be luck to last a few thousand miles. A 130 lb cyclist who "rides light", pedals smooth circles on a well designed and welded frame can expect many years/thousands of miles. Also, even the best companies can turn out a lemon now and then, and there's no way to detect problems under the paint. So, no answer to your expected life. As to failure modes, you should inspect regularly for cracks in the paint and then explore whether they go into the metal. Wobbly means that things are already coming apart. And if you don't do inspections or detect wobbles well, things can come apart and seem like a catastrophic failure. Not very common, BTW.|
Sep 17, 2001 7:27 PM
|I raced a cannodale Al frame for 8 years...then changed it for another aluminum frame (no brand names mentioned) and it broke in ONE season... Frames are like a box of chocolate, you never know what you are gonna get. :-)|
Sep 18, 2001 5:41 PM
|I do agree with you, it's the manufacturer that ultimately determines the quality of the frame. I can think of several components (frames, wheels, etc.) whose weight and the material used was very suspect to me and I'm not a mechanical/structural engineer by trade. I think with proper construction techniques it is possible to make a good frame that is very light and strong. Personally, if I were to chose such a frame I would only use those manufacturers that have the industry experience and technology to do it correctly and have been around long enough to know how to avoid product liability lawsuits. :) All opinion of course.|
Oct 8, 2001 5:41 AM
|I only have experience with Cannondale. CAAD5 and CAAD6 frames specifically. They have been quite durable. However, they are made by Cannondale which makes their own tubes, and has lots of experience.|
|re: Aluminum Frame Durability||Mark Dennis|
Sep 18, 2001 12:52 AM
|Hi. I used to be into Motor Bikes before I decided that I had to give them up to stay alive. I read a book once specifically about making Motor Bike frames and one interesting thing I gleened from it was that in the context of frames, Aluminium has a finite number of flexs before it will fail. The author also said that Steel has an infinite number of flexs and doesn't fail, it may just get a bit softer over time. The biggest qualifier for this I think is that the flexing is within the normal range specified for the design of the frame so we are talking about normal operating loads.
I have only heard about 1 bicycle frame actually breaking and that was a mediocre quality steel frame that broke the down tube near the bottom bracket. There may have been corrosion involved here. I have heard of one person having to replace their Alloy frame which had developed a crack near the steerer tube and my alloy seat post on my old MTB cracked and I actually broke it while taking it off to replace (lucky it didn't break while my fat arse was on it).
I think that Alloy and steel frames would both have a very long but finite life, but as long as you keep an eye out for cracking every time you wash the bike, you would be able to catch anything before it gets serious. I reckon you should get many many years from any quality frame and Colnago are reasonably good quality aren't they? ;-)
Alloy frames ride as rough as guts though I reckon and that's why I have a steel frame road bike.
|re: Aluminum Frame Durability||snaillich|
Nov 2, 2001 10:49 AM
|It's less about the aluminum as a bulk material and more about the welds and evn more importantly how the metal grain structure is refined after welding by heat treating processes. Alum is rigid and until the tensile strength is exceeded will be every bit as durable as steel. Althoug aluminum will typically give (break) all at once while steel with higher elasticity will stretch and get floppy before it tears. With aluminum it is most critical to heat treat and remove stresses at the welds and adjust the grain structure to be consistant with the bulk frame tube material.|
|re: Aluminum Frame Durability||Woof the dog|
Sep 18, 2001 10:49 PM
|Who cares, dude. Get the best lightest aluminum frame and don't worry about it. You will get a new frame for free if you break this one, just check the policy of the company you are buying a frame from. That means you can put it through a lot of abuse, its like disposable gloves. I am not kidding ya. Usually cracks are near the bottom bracket (shell I think, and especially near the bridge), another common place is rear dropouts. You can detect if there is a small crack developing by crack in paint, thats how I saw mine. If it snaps there, you will feel your wheel rubbing the chainstays, but if you take it easy till home, you will have a new frame within 2 weeks from LBS. Sounds good to me. Just check bottom bracket and rear dropouts periodically. Cool bike is not really an investment, but you know that, right?
Woof the dog.
|re: Aluminum Frame Durability||DaveG|
Sep 19, 2001 8:35 AM
|Woof, from a warranty perspective your argument is sound. But when you say "who cares" I'd offer that I would care if I were careening downhill at 40mph or on a long ride when that snap occurred. I'm not down on light bikes. But unless you are riding at a highly competive level, why take a chance on durability if you are not in a position to gain from the weight reduction? I just want to ride. I don't want to stay up nights worrying when my frame is going to snap. Besides, if you have a super-light bike and you still are regularly dusted by guys on much heavier bikes, then you are now completely out of excuses.|
|re: Aluminum Frame Durability||Leisure|
Sep 20, 2001 4:18 AM
|I agree with both of you- Don't worry about it so much because unless you're a big-budget or sponsored racer then there's no reason to get the absolute lightest production frame available. That being the case, get something a bit heavier but more durable that you won't have to worry about any time soon. As far as aluminum is concerned, I don't hate it. I also don't particularly like it. Longevity and weight are great and all, but you can assume that most reputable frames aren't going to stray too far from industrial norms in either parameter. After that it's all about ride quality, something a lot of people don't pay enough attention to. Heck, ride quality is actually about the only thing I look at. In mountain biking that means (for me at least) full-suspension which is best handled with aluminum, maybe carbon in some specific applications. In old-school triangular road biking frames, you generally get a better ride on steel or Ti. I went with 853 Waterford, and oh my gosh it rides sweeeet. Not as thoroughly majestic as a Seven Axiom, but when the frame costs 20% as much I don't complain. One question I forward to lots of riders is, Why are you doing it? Do you truly love to ride, or is it more ego? Be honest with yourself, because it's a bit of both for everyone (including your truly), and go from there.|
|re: Aluminum Frame Durability||Leisure|
Sep 20, 2001 5:18 AM
|I just realized I goofed my last post by forgetting to directly address the original issue. (Sorry, I had to rush to an errand.) Just go research a) your frame's weight, b) the tubes used i.e.- Easton such and such grade, c) approximate average frame weight for your application, d) your body weight, and e) company integrity. Altogether you'll get a rough idea of how safe you are compared to everyone else, and therefore how easy you'll want to go on your frame. You (Mapei) sound like the type that isn't going to uselessly abuse your equipment, which is good. The fact that you care means that you'll most likely see problems coming before they surface, and will better avoid them. Assuming your bike is fairly new, you've got plenty of time to feel-out your frame. In other words, the fact that you're obsessing about it is the reason you're probably going to be just fine. Enjoy, and ride.|
|re: Aluminum Frame Durability||Mapei Boy|
Sep 24, 2001 11:13 AM
|Thank you, Leisure, and everybody else for responding to my question. I appreciate all the responses, even the snide ones. I will especially watch for those telltale cracks. As for what I am (at least bicycle-wise), I'm just a guy who likes to zoom down the road on a thoroughbred bike. I don't race, and I don't care whether the people I happen to come across while riding are slower or faster than me. It's enough that there's another roadie out there, sharing the good times. Because I like to climb hills, my bike bias is toward light weight rather than a cushy ride...though this doesn't mean I want to be jackhammered to death, either. In any case, thanks again for all your responses. See you on those streets.|
|time to change||guiseppe|
Sep 24, 2001 12:31 PM
|better get a C40... that's what Mapei is riding now.|| |