# higher number is better?



## rich1374670x (Jan 21, 2011)

Looking at two bikes one is 6061 aluminum, the other is 6066. What is the difference. Thanks rich


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## Nenbran (Dec 7, 2010)

Google is your biggest friend when it comes to matters like this. You probably won't find too many materials experts on an open forum. That being said, they are just different alloys...they have different amounts of different trace elements in each alloy. But to be honest, if I were you, I'd look into a bike with 7000 series aluminum, not 6000.


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## Trail Ninja (Sep 25, 2008)

# 6000 series are alloyed with magnesium and silicon, are easy to machine, and can be precipitation hardened, but not to the high strengths that 2000 and 7000 can reach.
# 7000 series are alloyed with zinc, and can be precipitation hardened to the highest strengths of any aluminium alloy.

From what I understand, 7000 is much harder to weld but it is generally stronger and lighter. It's a lot more expensive.

To answer your question, no, higher number is not necessarily better. The number designates what alloys it contains. It's coincidental that 7000 is better for bike frames than 6000. Good question though, I killed an hour trying to find out. 
*Nenbran*, Google really sucked on this one.

I couldn't find any information that would explain the difference between 6061 and 6066 without going through the list of alloys in each one, figuring out which alloys are good for bikes and then calculating which one had the best percentages of those alloys.

If you want to do it, have at 'er

http://en.wikipedia.org/wiki/Aluminium_alloy


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## cobba (Apr 5, 2007)

> higher number is better?


Not necessarily

With Giant you'll find 2 grades of Aluminum Alloy, Aluxx and Aluxx SL.
Aluxx is 6061, it's found on their lower end bikes.
Aluxx SL is 6013, it's found on their higher end bikes.



> 6061 v 7005
> 
> 6061 and 7005 are the two most readily available aluminum alloys appropriate to making bicycle frames. We're also beginning to see 6066 and 6069 become available from some tubing manufacturers, but only on a very limited basis at this time. "Scandium" as used frames is actually an aluminum alloyed with a small amount of Scandium, yet is much too expensive for the general market. There are many other aluminum alloys like 7075 and 2014 that are stronger than both 6061 and 7005, but are not appropriate to making bike frames because they are nearly impossible to weld.
> 
> ...


The cost of equipment in the frame factory might be a determining factor whether a company makes frames out of 6061 or 7005.

6000 series aluminum is more corrosion resistant then 7000 series aluminum.

7000 series aluminum is harder which makes it more brittle then 6000 series aluminum.


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## faceplant72 (Oct 25, 2009)

http://www.matweb.com/

If you want to burn a afternoon comparing matterial is will give properties of most Al alloys. BTW there are ~10 different 6061 variants allone


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## Nenbran (Dec 7, 2010)

Trail Ninja said:


> *Nenbran*, Google really sucked on this one.


Alas! My favorite tool has failed.


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## perttime (Aug 26, 2005)

Don't worry about those numbers too much. What the designer and manufacturing do with the material is more important.


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## Nenbran (Dec 7, 2010)

perttime said:


> Don't worry about those numbers too much. What the designer and manufacturing do with the material is more important.


That's true, but only to an extent...you're looking at a significant difference in strength between 7000 series and 6000 series aluminum. Design can only compensate so much.


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## perttime (Aug 26, 2005)

So, the designer hopefully uses enough of the material that is weaker in some way...


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## CaveGiant (Aug 21, 2007)

Nenbran said:


> That's true, but only to an extent...you're looking at a significant difference in strength between 7000 series and 6000 series aluminum. Design can only compensate so much.


However 6000 allows more versatility in frame design (notice most heavily hydroformed frames are 6000). I would go that the difference in design is more significant that the difference in material.


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## Nenbran (Dec 7, 2010)

You two make very good points. My only concern is that it leads to a heavier frame. But for some people, that isn't an issue. I concede to your points.


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## rich1374670x (Jan 21, 2011)

So back to why I posted, is 6066 better than 6061.


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## Nenbran (Dec 7, 2010)

rich1374670x said:


> So back to why I posted, is 6066 better than 6061.


Somewhat. Though I'll just say it again that Google is a valuable tool. I googled "6061 strength" and "6066 strength" and it looks like 6066 has higher tensile, yield, and shear strengths. But not by too terribly much.


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## perttime (Aug 26, 2005)

rich1374670x said:


> So back to why I posted, is 6066 better than 6061.


The answer:

Not necessarily.

Depends on what the designer did with, and how well the factory executed the design.


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## rzozaya1969 (Nov 28, 2004)

Nenbran said:


> That's true, but only to an extent...you're looking at a significant difference in strength between 7000 series and 6000 series aluminum. Design can only compensate so much.


Numbers are numbers, not the highest are better. More boutique DH bikes are 6xxx series, while other brands use 7000 series. I think that each have advantages, and some are easier to manufacture.

I think that 7000 series are easier to manufacture, so more mass manufacturer use that, but 6000 series can be more rust resistance? (maybe).

Anyway, I think bike design is a lot more important than the actual alloy number.


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## Nenbran (Dec 7, 2010)

7000 is easier to manufacture? I thought it was 6000.


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