Difference between aluminum types?
 

Ok. Now that Im close to zeroing in on a groupo, when i thought I was set on a frame, Im wondering.

Ive heard the "steel is real" line a thousand times, and used to ride a steel ss. Just as there are dif types of steel (531, 4130 etc?), I believe there are different types of aluminum. 7005 and some other type..6061 i think, but im not sure since Ive never ridden an alum road bike.

Whats the difference which is the higher quality, what are advantages/disadvantages of both, for a beater, every day bike that can take a beating, which would you suggest, assuming I am not buying a steel frame.

Asside from that, anyone got any good steel frames out there to build on? Preferably American

What do you mean by "a beater"? If you want a bike that you can ride around town, use as a commuter and lock up outside your favorite bar or library, then alum might not be the best choice. Alum frames tend to have very thin walls, and dent pretty easily. They are great for road riding, but you have to be a bit careful that you don't drop them, or that someone doesn't drop something onto them.

If you still want an alum frame I wouldn't worry too much about the type of alum and instead consider the manufacturer. Cannondale is a favorite around here for alum with the CAAD series, but most manufacturers make alum frames. There are also a lot of cheap alum frames (Bikesdirect or performance for example) that are very ridable and could be easily replaced if crashed or dented.

The last half of your post is just about right but the first part is dead wrong. Aluminum is soft and can be dented but it's no more prone to dents than thin steel or any other much thinner metal. If anything, aluminum has a thicker wall than just about any other material to make it more dent resistant. There are literally millions of mountain bike frames out there that are made of aluminum that get dropped, crashed and abused daily without issue.

ph4nt0mf1ng3rs: 6000 series aluminum and 7000 series aluminum are both used in building bikes. 6000 series aluminum is used on less expensive bikes because it's an inexpensive alloy that is mostly aluminum. 7000 series aluminum has lots of zinc, magnesium and copper in it so it's stronger, i.e higher yield and tensile strength. Stronger means that the frame can be made just as strong as the cheaper material but with less metal so the frame is lighter. It's also more expensive. That's the thinner tube that hammond9705 is talking about.

Low level bikes are generally 6000 series aluminum while more expensive bikes are 7000 series. A 6000 series road bike...the Trek 1.1 for example...is around $700. A 7000 series bike...the Trek 2.1 for example... is around $1400. There are component differences which make the price comparison dodgy but part of the cost difference is the frame material. Generally speaking, you don't hang really good components on 6000 series frames and you don't hang cheap components on a 7000 series frame.

If you are looking for a general purpose, don't worry about it bike, I'd go for the 6000 series bike. Save some money for a special uber bike later on.

I think you're both right and wrong at the same time. The top tube of my (scandium aluminum) road bike has such a thin wall in the middle, it looks like a soda can. It almost seemed like the wind could dent it, and a wood box falling on it ended its life. My mountain bike, however, has been dropped multiple times without a dent. So, it depends on which frame you're looking at, and how thin they make the walls.

Steel is the same way. If you're looking at "oversized" steel tubing, you're probably looking at something with thinner walls. If Reynolds 531, not so thin. Even then, some tube sets are butted and some aren't.

like Cannondales? http://www.cannondale.com/usa/usaeng...on?faq_id=7#Q3

Like Kinesis/Motobecane? http://www.bikesdirect.com/products/...agesport_x.htm

Thanks for the help guys.

I still do believe that Steel is the way to go, but am still researching aluminum frames to make sure I leave no stone unturned.

The 2 main disadvantages I see to steel are weight and prone to rust. If neither of these are a concern to you, it's a great choice. I might also add that titanium rides a lot like steel in my experience, replacing the rust issue with the cost issue.

FYI, I don't believe the 2.1 is 7000 series aluminum, at least not for 2011. Their website shows the 2.1 as using "Alpha Black Aluminum" which is described as:

"Trek’s high-performance aluminum alloy, Alpha Black is 6000-series aluminum that has been hydroformed or mechanically formed to optimize the tube shape and butting profile. Alpha Black frames may be smooth welded for aesthetics."

IIRC, 6nnn series alloys are weldable but 7nnn series alloys are not.