# 7005 vs 6061 Aluminum, what is difference?



## NaplesTopless (May 20, 2006)

I been riding a Felt 90 (road bike) for about a year and want to upgrade to a better bike in the $1,500 range (give or take a $200). The Felt is made with 7005 Aluminum while the IBEX I am considering is made of 6061 Aluminum, does anyone know what the difference is and should I care. I just spent 45 min using the search trying to find the answer on this forum but the one thread that I found that might have answer my question used links that are no longer valid.

I am thinking that it is better to get a good frame with better components than a better frame with lower components


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## TylerDurden (Jan 28, 2006)

from looking at matweb.com, it looks like 7005 is slightly stiffer, stronger, and heavier than 6061, but not by too much. I think 6061 is a lot more common in bikes, but I don't think these differences should be significant enough to make a decision on. (density: 2.78 vs 2.7 g/ccm, stiffness: 72 vs. 68.9 MPa)


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## rogger (Aug 19, 2005)

The differences between alloys are insignificant compared to differences in build quality. Tube/frame manufacturers would like you to think one is more high-zoot than the other for reasons of sales competition. 6061 is an alloy that is widely used in various types of industry and is easy to work with, aluminum framebuilding pioneers used this alloy to great succes, 7005 was introduced later as a more high-tech alloy, mainly for marketing reasons. If you are going to decide between frames, look for the right geometry first, price second, looks third and then follow stiffness, warranty and service, finish of the frame, type of headset needed, braze-on FD or no, tire clearance and finally type of alloy.


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## Dave_Stohler (Jan 22, 2004)

I know that the guys in the machine shop love 6061-T6 because it is extremely easy to work with, and is probably the least expensive of the common commercial grades. you can buy it in bar stock, flat stock, rod, tube, hexagonal bar, you name it, it's available. I would also guess that it's much easier to do butting and swageing on extruded tubing, as well. I believe Cannondale has always used 6061-T6 aluminum.


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## ibexbikes (Apr 28, 2004)

*6061 vs 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. 

6061 (aluminum/magnesium/silicon alloy) is generally considered superior to 7005 (aluminum/zinc alloy), though in some respects 7005 can be stronger. The tensile strength of 7005-T6 is 51,000 psi vs 45,000 psi for 6061-T6. Yield strengths are 42,000 psi vs 40,000 psi, respectively. Tensile strength measures the amount stress required to cause complete failure, while yield strength measures the amount required to deform the material. The problem is that the ratings are measured on solid aluminum. When to comes to frames, the greatest differences in strength will come from the quality of the welds, selection of tubing shapes and thicknesses, and the overall design of the frame.

The truth is, in terms of the forces that a bicycle frame is typically subjected to the base material strength differences between 6061 and 7005 alloys are fairly negligible. You are unlikely to ever put more than a fraction of the stress on your frame that would cause it to reach those force levels. Nevertheless, the 7005 is the stronger of the two in those respects (6061 is superior in stretch resistance, but again those figures are far outside of the realm of real world use). So why do I say that 6061 is considered to be the superior material for making bike frames?

As mentioned by several posters, 6061 is easier to manipulate making butting and tube shaping like ovalizing and tapering less costly. On the other hand, 6061 requires precise liquid cooling as part of the heat-treatment process that all aluminum bikes frames must undergo after welding, whereas 7005 can be air cooled. The bottom line was touched upon by an earlier poster, but is essentially that we can execute a better and lighter design easier with the 6061. Due to the degree of manipulation, and the liquid quenching, a 6061 frame is typically more expensive to produce. It used to be a considerable difference just a few years ago, but 6061 frames have become more reasonable over the last few years as the technology and equipment proliferates.

Here at IBEX, we much prefer 6000-series alloys. We have completely phased-out 7005, and will begin introducing 6066 and 6069 tubesets on a few high-end models next year. In the meantime, 6061 is our mainstay and it will remain so on the vast majority of our models for some time to come.

Best regards,
Jack A.
IBEX Bicycles


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