Carbon or aluminum?

Hey I'm in the research phase of getting a new bike. Right now its between the 08 Specialized Tarmac Elite, or 08 Specialized Allez Elite. The Tarmac is full carbon, and costs $1950. The Allez Elite is aluminum with carbon seatstays, seatpost, and fork, and it costs $1600. One of my questions about aluminum compared to carbon is strength. Which material holds up better in a crash, and which material has better longevity?

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Pain is temporary. It may last a minute, or an hour, or a year, but eventually it will subside and something else will take it's place. If I quit, however, it lasts forever. -Lance Armstrong

I would say go for the all carbon tarmac. I was in the same boat as you until I finally made up my mind earlier this week and put my money where my thoughts were. Put a deposit down on a Cervelo r3sl. I have a aluminum Raliegh Cadent1 with Kinesis aluminum frame, it survived a crash with a car but then again the seat and the handlebar took the brunt of the hit. Not even a scratch to the frame, so?? I guess that doesn't help much. But it sounds like your ready to buy. Personally I'm not a big fan of multimaterial frames.They seem like there trying to fill that void between the latest tech. and old school. I believer there also selling themselves as having a smoother ride instead of all aluminum but I hardlely believe carbon stays make much difference. If your gonna get something thats already 35% carbon why not go for 100% and reap all the benefits that go along with it. Plus a difference of 300 dollars in price is nothing.

For all practical purposes, no difference at all. Seen both types get completely butchered in crashes - alu frames torn apart, carbon frames with gaping punctured holes, etc. Crash-worthiness is probably not a good characteristic to try to judge frames by. Longevity - for all practical intents, both will last as long if they are not crashed in a spectacular and catastrophic manner....regardless of material.
Which one fits you better? Are you limited by a budget? Which one is more aesthetically pleasing? Any of these would be better criteria for getting a bike.

well just seeing that carbon weave will make me want to attack every hill in sight, however the money left over from buying an aluminum bike could get me an giro atmos, giro advantage, a garmin 305 (really want one of those), cheap disk wheel, etc.

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Pain is temporary. It may last a minute, or an hour, or a year, but eventually it will subside and something else will take it's place. If I quit, however, it lasts forever. -Lance Armstrong

If that is the case, go for the alu. A disk wheel and the Giro Advantage will make you much faster than any carbon frame without those accessories would.

It really depends on the distances you ride, if you only do 10-30 or so you could go aluminum, if you do more, then I would go carbon. Aluminum is very stiff and beats you up on the longer rides more so than carbon.

sheesh...how many times does this old myth have to be buried and put to rest? do a search and you will find plenty of evidence that this is nothing more than an old wive's tale. Geometry and construction methods trump frame material....there are plenty of noodly alu frames just as there are uber-stiff carbon frames and steel frames which fail way earlier than you would have guessed....check out the tests at the German EFBE bicycle testing institute and you will see what materials, frame stiffness, (and by extension, comfort ), and frame longevity have to do with each other: nothing at all...

Brian,

I have several bikes, some carbon, some aluminum and I notice a distinct difference between the two. I do agree that geometry has a lot to do with it, but the way that most aluminum bikes are set up makes them a stiffer ride than their carbon counterparts.

I honestly am not an expert so I only speak from my experience, but I know I am much more comfortable riding over rougher roads and hitting bumps on my Orbea than on my aluminum Trek. In fact, I have had problems with my lower back after doing longer rides on my Trek aluminum due to the constant jarring of the aluminum frame so if I go over 50, I will always take the carbon.

You typically don't see anything but round tubes on aluminum bikes, where on carbon they will be all different shapes, do you have any idea why this is so?

Interesting....I wonder how much of a part the psychological aspect plays in our perception of comfort? The reason I say this, is that I have owned a few carbon bikes as well: a Giant Cadex, a Look 171 and 281, and a Quattro Assi, and will concede that the carbon frames were QUIETER over most roads....especially compared to the steel-framed Panasonic and alu Cannondale I rode before those. However, the big bumps were still the same - meaning that they were transmitted the same as on other bikes.
So, I don't know that there would be much (if any) difference in comfort between materials....a few years ago, I put on 25c tyres for training, and these made a much bigger difference than anything else.
As for different shapes....carbon can be made into any shape possible because you just need to change the mold. Alu or steel has limits on the shapes that can be rolled out. Although, Columbus and Dedacciai created some interesting tube shapes in their alu lines (until recently concentrating on carbon), also hydroforming has been used the past few years to give interesting shapes to alu....witness the typical "pyramid" shaped downtubes used in the Airplane/Zonal/Starship tubes, which were created to give stiffness in one direction (lateral) and a measure of compliancy in the other. Seatstays shaped like the now-common "hourglass" were also used by Cannondale and Columbus to mute (ie, give the shocks from the road a longer more circuitous route to travel through the frame from the wheels). Interestingly enough, most carbon seatstays also now use this same shape!