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A Question In The Property Of Aluminum(29 posts)

A Question In The Property Of AluminumRadicalRonPruitt
May 7, 2002 4:16 AM
Every notice, when you step on board an airplain, how thin the aluminum walls of the fuselage is when compared to the weight of plane. Yet it is stable enough to cary the plan for years without problems in most cases. Yet, bike companies like Bianchi, can't make an aluminum frame that last more than a season. Is there that much difference between the two types of aluminum?
Not reallyRusty McNasty
May 7, 2002 5:29 AM
But, the types of loading are quite diferent. A racing frame doesn't have to last more than a single season, whereas a plane does. Also, the walls of the fuselage are'nt the major load-carriers of the structure-the spars are. You are comparing apples with oranges here.
Not reallyRadicalRonPruitt
May 7, 2002 5:39 AM
What are the spars?
Aluminum is aluminumUncle Tim
May 7, 2002 6:03 AM
Though there are grades, the aluminum in/on an airplane is just like the aluminum on a bicycle frame. It's just fabricated much differently because the functions are much different. Aluminum siding is very light aluminum, but that doesn't mean you can make a bicycle frame out of the same stuff.

An airplane has a superstructure (spars) that you can't see that basically holds the thing together by managing the forces that push and pull on the airplane. Those spars are not tubes made of very thin layers of aluminum. The superstructure is not anything like the aluminum panels you can see.

Unless some kind of breakthrough is made in the production of aluminum, it is going to be difficult to make aluminum bicycle frames a whole lot lighter than they already are. The loads are rather high in some places and shaving the thicknesses down or making smaller welds will seriously compromise safety.
Cannondale Cut In HalfRadicalRonPruitt
May 7, 2002 7:18 AM
I have seen a Cannondale cut in half and it was scarry to see how thin the aluminum is. Makes you think if you really want to be riding on something with walls that thin.
Cannondale Cut In HalfJekyll
May 7, 2002 7:24 AM
Ever seen a high end steel or worse yet CF frame cut in half? Just as scary. From talking to guys I ride with from the C-dale factory, if you think that the CAAD4/5/6 are scary thin, wait till you look at the CAAD7.
Makes one really appreciate the amount of engineering that goes into making ultra light weight frames (and hope the guys who designed it did not drink their way through college).
Cannondale Cut In HalfRadicalRonPruitt
May 7, 2002 7:29 AM
What is Cannondale doing with the Caad 7 to make them thinner and stronger?
Cannondale Cut In HalfJekyll
May 7, 2002 7:36 AM
They claim that their new "Optimo" alloy can be formed into a thinner, stronger, lighter and more comfortable frame. Their claim is that Optimo has a 15% higher tensile strength allowing them to use less to get more. The weight on the CAAD7 is lower than the CAAD6 - 1180gr for a 56cm frame - pretty damn light.
I'd like to ride one but I have yet to see one in person.
BTW - they have a great ad for it in the new Bicycling waste of a tree.
here's what they say....Jekyll
May 7, 2002 7:38 AM
http://www.cannondale.com/bikes/innovation/caad7/
see spars here....EpicX
May 7, 2002 10:23 AM
http://www.boeing.com/companyoffices/gallery/images/commercial/747400-20.html
skin .vs. boneSteveO
May 7, 2002 6:30 AM
My 2 bits on Aluminum.mixinbeatz
May 7, 2002 7:41 AM
If anyone is afraid to ride aluminum, they should not. Aluminum bikes do break, in fact I broke a frame in two a couple weeks ago in a race. Would I not ride aluminum because it occasionally breaks, of course not. For me, the lightness of the frame and performance outweigh the chance of crash failure. Aluminum bikes break because of poor manufacturing or bad crashes and should not fail under most normal riding. If the benefits of aluminum do not outweigh the risks, than don't ride one. Just understand that if you do ride one, a severe crash will most likely damage the frame. If I would have crashed a steel bike, I would have had to most likely replace the fork and or wheel(and possible bent frame), somethings got to give.
Well saidgrandemamou
May 7, 2002 9:39 AM
I have one AL bike and 2 steel and they all great in their own right. The idea that one frame or one material is perfect for every rider in every condition is ludicrous. If you are a lighter rider and want a lightweight, inexpensive frame, AL is the way to go. I don't expect it to last forever. It comes with a 5 yr warranty if it makes it to 5yrs I got my moneys worth. If it does not, I get a new frame.

I have never seen an AL frame fail catastrophicly while JRA. Not saying it hasn't happened, just that I have never witnessed it with my own eyes.
There is a huge difference.firstrax
May 7, 2002 8:11 AM
Aircraft are made from 2024 alloy. Very hard (120 brinell), not very light and superb yield strength (47 ksi). It sucks for welding though. Which is why you dont see it on bikes much. Also explains the rivets on aircraft. You probobly dont want a bike made from this stuff if you think C-Dales have a harsh ride now.

6061 alloy has good welding properties, very formable and has high corrosion resistance. Yield strength is 40 ksi and the hardnes is 95 birnell. More manufaturing freindly for bikes.

The biggest difference is the 2024 has a lot more copper, manganese and zinc.

Aircraft also get x-rayed every so often to find small fracture before the become large ones. Bikes dont.
The Other Half of the Storygrzy
May 7, 2002 9:41 AM
No one has mentioned the most sigificant factor in dealing with aluminum: heat treatment. Without heat treatment most aluminum is pretty soft. Welding destroys the heat treatment properties in a given component *unless* the whole frame is then put back in the oven and the properties reintroduced. Many companies don't do this b/c it's costly and time consuming. At the end of the day aluminum is more expensive than steel, but since it's so light it is easy to over engineer to achieve a relatively light, albeit stiff, throwaway frame. Fact of the matter is that most bike companies spend peanuts on R & D testing and then errors and shortcuts occur when it comes time to go into production and fabricate. the aerospace industry spends a few more dollars to ensure that they get it right. The cost of a C'dale frame is surprisingly low and it all goes along with light, cheap, and durable - pick any two. BTW - many moder military airfcraft now make heavy use of composites due to superior strength to weigh issues.
The Other Half of the StoryRadicalRonPruitt
May 7, 2002 10:16 AM
Which companies do and which companies don't retreat the frames with heat?
The Other Half of the Storyda cyclist
May 7, 2002 10:22 AM
Bianchi reheats their frames.
The Other Half of the StoryRadicalRonPruitt
May 7, 2002 10:34 AM
They have a really bad rate of frame failures around the bottom bracket.
Data pleasegrandemamou
May 7, 2002 11:01 AM
Do you have any data to back that up?
Bianchi EV2 and EV4RadicalRonPruitt
May 7, 2002 11:36 AM
It is well known on this message board that the Bianchi EV2s are prone to fracture in the bottom bracket area. I am sure that Bianchi doesn't make this info public, but if you read enough on this post, you will find out. Secondly, they won't let the Team Coast boys train on the EV4 because they are even lighter than the EV2. My guess is that they won't hold up form even a season if that is the case.
With Due respect,TJeanloz
May 7, 2002 12:26 PM
I sold a LOT of EV2's (and its predecessor, the MegaPro XL), and I warranteed a LOT of them. By a lot, I'd estimate we sent back ~15 or so frames. Not one was broken at the bottom bracket. I don't know where you picked this tidbit of information up, but it is news to me.

Most of the fractures that we saw were very near the STI/Ergo braze on. Also a few in other choice areas, but not typically at the bottom bracket. So, I would say that it is well known that these bikes have a high failure rate, they are not particularly prone to fracture at the bottom bracket.
My Experience With Bianchi EV Aluminum FramesRollinFast
May 7, 2002 7:42 PM
I bought my first EV series AL Bianchi frame in 1999. This was the model that looked like the bike Pantani won the Giro and the Tour on. I had no problems with this frame up until the point I took it in for a winter tune up. The mechanic noticed the front derailleur bracket that Bianchi included with the frame pinched the seat tube. Bianchi replaced the frame with a 2000 EV2. I rode this frame from February 2000 to late July 2000. The last week of July I noticed a hair line fracture developing on the seat tube just above the bottom bracket. My shop warrantied it with another EV2. I rode this EV2 from August 2000 to early October 2000, 2000 miles, and I noticed a hairline fracture developing in the exact same place on this frame. The mechanic at the shop warned me that he was worried about this frame because the serial numbers were close. (don't know if that is relevant) Unable to get my size of frame until the next year, I opted to go with the Boron Mega Pro Bianchi frame, but did not like the ride characteristics. Overall, I loved the Bianchi EV2, however, I did have some problems with the frame holding up. I weight from 168 to 175 pounds during riding season and I do own a set of tree trunks for legs. I gave up on Bianchi after the boron steel. I miss the ride, but not the hassle.
yes, lets not confuse any one with factsgrandemamou
May 7, 2002 3:22 PM
Well known? We must not be looking at the same board. I searched the message boards back about a year there is 1 post by someone who had a friend whose chainstay broke. 1 post by a guy who had a "friend" who claimed to have dropped the Bianchi line, several posts by TJ who doesn't seem to like them very much and a whole bunch from me and several other posters who do.

When I bought mine I questioned my bike shop about the rumor that I heard about alot of failures. He said that he sold 10-20 a year over the past few years and has had 2 come back. I trust the guy, if I did not buy the Bianchi from him I would have bought a Colnago.

Again where is the data? You know the facts. I sold 100 and 5 came back so thats a 5% failure rate. Not I had a friend whose uncles,brothers,cousins, ex-wifes son worked at a bike shop and hads tons of them come back.
For the record,TJeanloz
May 8, 2002 4:17 AM
I like the EV2 very much, and I think it has a place in the pantheon of bicycles. It is (or was, when it came out) a marvelously light bike. Many of them will break. But Bianchi has always been faithful with warranties, so I don't see that as a real drawback. If I were building a bike to climb Alpe d'Huez, I think I'd start with an EV2.

Total Bianchi MegaPro/EV failure for our shop was probably running close to 75%. But there's a good reason: our Cat 1 team rode them, and they abuse their bikes. I think every one of theirs broke within two seasons. So if we exclude the 25 or so bikes that those guys had, and count only failures among paying customers, it was probably more like 30-40%. Still unnacceptably high, but it wasn't a problem because Bianchi stood behind their warranty, and everybody knew where to look out for cracks.
Bianchi Warranties,RollinFast
May 8, 2002 4:50 AM
Bianchi did a great job of standing behind their warranties. However, I from a conversation with my LBS, I did notice they changed the warranty from lifetime down to 3 years, which is lower than the standard warranty offered by most frame makers.
They did,TJeanloz
May 8, 2002 5:14 AM
There was a lot of debate about changing the warranty to three years on the MegaPros (I believe it's still lifetime on the lower end). But the dilemma was: we can build a great bike, but we know it won't last forever. Do we build said awesome bike, or do we deprive the world of it because it isn't durable enough? I like their solution.
Facts, thats what I meantgrandemamou
May 8, 2002 5:23 AM
It bugs me when people make blanket statements about materials or frames. You usually get it with C'dales and Trek OCLV. If you believe some people these are snapping left and right. About 80% of the people I ride with ride Trek,C'dale and Bianchi in that order. In the 5 yrs I have been riding with them I haven't seen a single one fail. FWIW we ride Cat 4 masters and the biggest guy is about 180. Do they break,yes is every other one breaking, no.

There is no "correct" frame or material. I weigh 145 and ride a 51cm frame. The Ev2 is perfect for me. If you weigh 250 and need a 61-63 IMO you are asking for trouble.
Heat treatment for alumimumNessism
May 7, 2002 6:03 PM
According to Columbus' literature, some of the alloys they use require heat treatment and others don't. Generally speaking, the higher strength alloys are able to be drawn thinner but require heat treatment.

http://www.framebuilding.com/Tubing-Materials.htm

Ed
bike metallurgyDougSloan
May 7, 2002 9:59 AM
http://www.sjsu.edu/orgs/asmtms/artcle/articl.htm

Pretty interesting.