Bicycle Mechanics - 6061 aluminum is NOT like 7075 aluminum. They're not even ALMOST similar!

Dear you who are reading, please spread the word: aluminum 6061 is much softer than 7075. 6061 is much easier to machine with CNC, because of its softness, but the chainrings made from aluminum 6061 alloy last orders of magnitude less, than those made from 7075 aluminum, due to the significant difference in hardness.

I am posting this, and hoping you will spread the word, because I'm up to here with dishonest sellers who take my money for a 7075 chainring and send me a replacement which is made of 6061, even though I clearly stated that I do NOT WANT a chainring made of aluminum 6061.

This particualr seller ran out the clock on me, so I could not start a complaint through the PayPal resolution center (45 days max after the transaction), but I still sent an e-mail to PayPal.

Sellers thrive on general ignorance. Heck, the in-built obsolescence of chainrings made of aluminum 6061 is a GOOD THING from their point of view, as you will be forced to buy a new chainring much faster than if it were made of aluminum 7075 or better yet, steel.


:notamused:

An what does this have to do with mechanic of a bike; did you buy it from this forum?

If you have an issue with a seller, and use paypal, you have 45 days, your fault for not resolving the issue before that, you obviously knew the product sent was wrong when you recived it, you should have sorted the issue before the 45 day limit was up.

sounds like someone did not do ay research.

An what does this have to do with mechanic of a bike; People who visit this subforum are most likely interested in facts related to bicycle mechanics; most of them want to learn new things that pertain to bicycle mechanics, and some may not yet know that not all aluminum chainrings are created equal.

People who visit this subforum are most likely interested in facts related to bicycle mechanics; most of them want to learn new things that pertain to bicycle mechanics, and some may not yet know that not all aluminum chainrings are created equal.
I think that fairly well known and most us us know enough to stay with reliable suppliers like Shimano, Campy, Suguino and some others. I know you are in Europe so did you buy from a European supplier or from the US?

Seems informative to me, for people that don't realize the aluminum you get does matter. He should have probably put the ebay anecdote elsewhere. He did say the seller ran the clock out on him, so the comments made to him by jimc101 are unjustified IMO.

Jimc

I guess I think this is a valuable post on this board. Did you or many others know this.

I personally found the post informative.

Why unjustified, the OP was having a rant about nothing related to bike mechanics, but to a bad buying experiance elsewhere, if it has been relevant to fixing a bike, fair enough, but if didn't.

For different types of Aluminium, there is far more to 6061(t6) than being softer that 7075, they have different properties, and are better suited to different applications google search it.

Wow. Thanks for the info on the differences. If I ever knew it I forgot it.
Replacing parts= bike mechanics to me...

Maybe I'm naive but I thought it was well known that there are a wide variety of aluminum alloys just as there are steel and Ti alloys. Steel used in bikes varies from "Hi-Ten" (low cost, low strength plain carbon steel) through several grades of Chrome-Moly up to the exotic high strength alloys like Reynolds 853. Titanium alloys vary in strength and durability from CP (commercially pure) grade up through 6/4 Al/V.

Aluminum alloys are also available in a wide variety of grades varying in strength, hardness, wear resistance and cost.

Thanks for the info, sorry to hear you got burned.


To all of those who thinks the OP was a waste:

Don't read it. Save your electrons for what you are interested in.

Not everybody knows the same things that you know, I thought the post was informative, thanks.

Why unjustified, the OP was having a rant about nothing related to bike mechanics, but to a bad buying experiance elsewhere, if it has been relevant to fixing a bike, fair enough, but if didn't.

For different types of Aluminium, there is far more to 6061(t6) than being softer that 7075, they have different properties, and are better suited to different applications google search it.

So product and material selection related to maintenance and part replacement has no bearing on mechanics, you say? I THINK NOT!

Thanks for the info, wroomwroomoops.

I am posting this, and hoping you will spread the word, because I'm up to here with dishonest sellers who take my money for a 7075 chainring and send me a replacement which is made of 6061, even though I clearly stated that I do NOT WANT a chainring made of aluminum 6061.

This particualr seller ran out the clock on me, so I could not start a complaint through the PayPal resolution center (45 days max after the transaction), but I still sent an e-mail to PayPal.

Have you tried negotiating with the seller, in spite of the resolution period expiring? A seller might be clueless like the rest of the public, not appreciating the significance of the difference in alloys.

In the past I bought a webcam from a seller who was a front for another seller and just copied info from some leaflet, never trying out the specifications. As the camera did not meet the specs, the seller refunded me and I even kept the camera. Conversely, I once refunded a buyer 6 months after his purchase, after it became that the problem was with the product and not any misuse.

at times, I've wondered why some parts were made from 60xx while others were made from 70xx aluminum, but now I think I understand better.

The OP's post begs a forum titled:

"cat 'post' > /dev/null"

=8-)

...and of course the OP is another in the long line of posters who can't seem to bothered to use the Bike Forums forum for vendor reviews...which is where the original post belongs.

I personally found the post informative.

Not really because it left out a real important part.

Most parts are made of 6061-T6 aluminum. The T6 is a heat treatment that significantly affects the properties of the metal.

The OP's post begs a forum titled:

"cat 'post' > /dev/null"

=8-)

...and of course the OP is another in the long line of posters who can't seem to bothered to use the Bike Forums forum for vendor reviews...which is where the original post belongs.

I didn't make a vendor review, I made a short and hopefully clear explanation on the difference between two aluminum alloys often used for bicycle chainrings. I stated that aluminum 6061 is much easier to machine, but the chainrings made from it last much less. For the maker this is an advantage: the softer Al 6061 will take less time to machine (and will require fewer CNC bit replacements) than the harder Al 7075. Also, the hapless user will be forced to replace the chainring much, much sooner than if the chainring were made from Al 7075, possibly leading to another sale. That is why I said that these people thrive on ignorance, and I would like to, at least a little bit, decrease that ignorance.

Furthermore, if you don't like this thread, just don't read it, let alone post in it.

OP, thanks for the info. I think a post that is about the durability of different and popular aluminum alloys definitely is of interest to me as a reader of the Bicycle Mechanics forum.

Not really because it left out a real important part.

Most parts are made of 6061-T6 aluminum. The T6 is a heat treatment that significantly affects the properties of the metal.

Good one Retro Grouch!


=8-)

"I am posting this, and hoping you will spread the word, because I'm up to here with dishonest sellers who take my money for a 7075 chainring and send me a replacement which is made of 6061, even though I clearly stated that I do NOT WANT a chainring made of aluminum 6061.

This particualr seller ran out the clock on me, so I could not start a complaint through the PayPal resolution center (45 days max after the transaction), but I still sent an e-mail to PayPal.

Sellers thrive on general ignorance. Heck, the in-built obsolescence of chainrings made of aluminum 6061 is a GOOD THING from their point of view, as you will be forced to buy a new chainring much faster than if it were made of aluminum 7075 or better yet, steel."


Word and Phrase Count:

sellers = 2
seller = 1
PayPal = 2
thrive on ignorance = 1
complaint resolution center = 1
dishonest = 1
money = 1
buy = 1
NOT WANT = 1

...sounds like a vendor complaint to me.

=8-)

Not really because it left out a real important part.

Most parts are made of 6061-T6 aluminum. The T6 is a heat treatment that significantly affects the properties of the metal.
It is true that aluminum alloy components are also characterized by their temper designation, but the fact is that practically all aluminum chainrings, chainring bolts and cranksets have T6 temper, be it 6061-T6 or 7075-T6. A 6061 alloy component, in any case, cannot be hardened to the level a 7075 component can. In other words, a bicycle component made of aluminum 6061 cannot reach the hardness it would have if it were made of aluminum 7075, regardless of the tempering the 6061 component is subjected to.

I didn't mention this in my opening post because the tempering doesn't change the fact that a 6061 alloy component will in all circumstances be softer than if it were made of 7075 alloy, and because I wanted to keep my post simple. I also didn't aim at perfection, because I would never finish writing the post and starting this thread, if I aimed at divine perfection.

What is the big deal about this post? It's of or related to bicycle mechanics, and if people are that offended, simply don't post.

6061 is about 30% softer than 7075, assuming a T651 temper, which is very common. However they've both very easy to machine, though 7075 has a tendency to flex a tiny bit, so depending on your surface finish requirements, may require a lighter finish pass. 7075 doesn't have the same corrosion resistance as compared to 6061 though. Hard anodizing parts takes care of the difference in wear characteristics between the two allows though :thumb:

some parts get cut in a whole, die cut, so that process favors the softer alloy
cost savings, in lower price points.
and in other thicker parts like crank arms is fine.

7075t6, Ergal in some descriptions, is better suited to cutting teeth individually..
CNC/CAM

numbers indicate a specific alloy mix.
7xxx series adds Zinc to the alloy, none in 6xxx
6xxx is trace Si [ .6%], not found in in 7xxx.

[Ref Machinery's handbook 23rd Ed, pg 604, nominal compositions]

Thank you all who found my post informative, or at least potentially informative for others who may not know the difference, or may think the difference is irrelevant - it is not irrelevant! We're talking 40.000 kilometers instead of 2000! We're talking about deformed teeth vs. just worn teeth, and only after a much longer time.

I will throw here a bit more of my brain/experience/knowledge here, and you be the judge if it's of value to you, or not. Also, if you have further info or corrections, please let me know so I'll update this post.


Chainrings that are known (to me at least) to be made of Aluminum 7075:
All-City track chainrings
Shimano XTR aluminum chainrings
All Salsa aluminum chainrings
RaceFace 3/32" aluminum chainrings
Sugino "75" track chainrings
All IRD chainrings
All VeloSolo chainrings
All aluminum Miche chainrings
All aluminum Stronglight chainrings
All current Specialites T.A. (AKA just "TA") aluminum chainrings
SRAM S-Works (and probably all SRAM chainrings - can anybody confirm?)
Blackspire Downhill (but not Epic Downhill, which is 6061) and SuperPro

Chainrings that are known to be made of Al 6061:
System EX track chainrings.
Sugino RD and RD-2 chainrings
Sugino 1/8" 110 BCD BMX chainrings (probably not in production anymore)
All Vuelta chainrings
Point-Racing DH chainrings
RocketRings chainrings
Dimension Components BMX chainrings
RPM road chainrings
All Origin 8 chainrings
Blackspire Epic (AKA "Economy") and road chainrings

At least some Sugino road and MTB chainrings seem to be made of 2014 aluminum, which is still harder than 6061!
The Sugino XD chainring is made of 2014 aluminum alloy.


Please fill in the ones I don't know about - like most of the Shimano and Campagnolo offering.

What is the big deal about this post? It's of or related to bicycle mechanics, and if people are that offended, simply don't post.

6061 is about 30% softer than 7075, assuming a T651 temper, which is very common. However they've both very easy to machine, though 7075 has a tendency to flex a tiny bit, so depending on your surface finish requirements, may require a lighter finish pass. 7075 doesn't have the same corrosion resistance as compared to 6061 though. Hard anodizing parts takes care of the difference in wear characteristics between the two allows though :thumb:

Thanks for this. As a material scientist, I find it arguable that hardness can be expressed as being x% less or more - it's just not a continuous value. That's why you have hardness scales. You know that material A is harder than material B, because A can scratch B, and not vice versa. And so you line them up, all of these materials, by way of using a certain test where these materials are measured one against the other. Based on the test used to compare the hardness of materials against each other, various scales have been developed, such as Mohs, Vickers, Rockwell and Brinell, to mention the most notable ones. I hope I'm not opening a can of worms here.

Very important is also your mention of corrosion resistance. I believe all aluminum chainrings are nowadays anodized. However, the hard anodized layer will quickly decay and flake off from the softer substrate on the teeth of an aluminum chainring. This is, sadly, true regardless if the chainring is 6061 or 7075 aluminum alloy, as these teeth are contending against the much harder steel of the chain. Still, corrosion doesn't seem to be a great problem for chainrings in general, as everyday mechanics experience shows.

The OP's post begs a forum titled:

"cat 'post' > /dev/null"

This is funny... :-D

Not bike mechanics related, but if you pay via Paypal, I suggest using a good credit card as your funding source. Then for any complaints, just ignore Paypal and go directly to your credit card issuer to get a complete refund.

Mavic made a group of components, CD anodized parts of it ,
and got the darkened colors to make it a feature..


anyhow..

we wait the Thesis, reference footnotes and scientific peer reviewed papers ,
, material scientist may be writing..

Mavic made a group of components, CD anodized parts of it ,
and got the darkened colors to make it a feature....
You can dye appearance anodizing any color you wish.

Mavic's "CD" hard anodized rims had the unfortunate habit of cracking prematurely as the brittle anodizing acted as a stress raiser for the underlying aluminum. The earliest rim failure I ever experienced was from an Open 4CD rim.

You can dye appearance anodizing any color you wish.That's correct. Anodized aluminum is actually porous alumina (Al2O3). Pore size and layer thickness are controlled by the anodizing parameters, including the electrolyte used. It's a hard but basically brittle material. Alumina can be made extremely porous - it's a popular choice for catalyst support.


Mavic's "CD" hard anodized rims had the unfortunate habit of cracking prematurely as the brittle anodizing acted as a stress raiser for the underlying aluminum. I believe this is at least partially if not entirely due to the great difference in ductility between alumina and aluminum.

CD anodizing on much beefier Ex 721, has no issues at all.

Hard anodized Ambrisio rims are, apparently, the Go To rims on the cobbles of the route to Roubaix

Here is an example of why reducing ignorance is important: two reviews of Blackspire Epic chainrings (http://www.mtbr.com/cat/drivetrain/chainring/blackspire/epic/prd_359632_112crx.aspx).

One reviewer wrote his/her conclusion after a long-term use of the product and even went to the trouble of characterizing the material the chainrings are made of.

The other only cared so much as to make sure the chainrings fit his/her 110 BCD crank and "appear well made." To conclude this disaster of a review, the reviewer writes "What else do you want! they are just chain rings!!"

I hope that more people could be upgraded from the latter (ignorant and proud of it) reviewer into the former (informed and inquisitive).

Not really because it left out a real important part.

Most parts are made of 6061-T6 aluminum. The T6 is a heat treatment that significantly affects the properties of the metal.
Precisely! There is more to it than alloy selection. The T6 Heat treatment specification is more important than whether or not it is 6061.

I can honestly say that I have never - not once checked on a material specification before buying a chain ring. I have always bought from manufacturers and sellers with solid reputations and never thought twice about it. I can't imagine putting enough wear into a chain ring in 45 days to even begin to make a claim thought pay-pal. There is more to the story here than materials - I suspect. If this was a used chain ring, not a surprise.

I might suggest that as an alternative to using the lowest price to determine part selection, the OP approach it from best VALUE for a quality component. This will almost never be the lost price but will in fact be the lowest cost.

Precisely! There is more to it than alloy selection. The T6 Heat treatment specification is more important than whether or not it is 6061.

I can honestly say that I have never - not once checked on a material specification before buying a chain ring. I have always bought from manufacturers and sellers with solid reputations and never thought twice about it. I can't imagine putting enough wear into a chain ring in 45 days to even begin to make a claim thought pay-pal. There is more to the story here than materials - I suspect. If this was a used chain ring, not a surprise.

I might suggest that as an alternative to using the lowest price to determine part selection, the OP approach it from best VALUE for a quality component. This will almost never be the lost price but will in fact be the lowest cost.
Aluminum chainrings are always T6 heat treated.

I find the rest of your comment quite insulting, like suggesting I can't tell a used chainring from a new one. Or suggesting that never checking the material specifications before purchase is a viable way of purchasing anything? How ludicrous is that?

I feel comfortable about putting you on ignore.

Aluminum chainrings are always T6 heat treated.

another overbroad generalization ,
unless you sold the aluminum to every factory in Asia.
:rolleyes::roflmao2:

What is the big deal about this post? It's of or related to bicycle mechanics, and if people are that offended, simply don't post.

6061 is about 30% softer than 7075, assuming a T651 temper, which is very common. However they've both very easy to machine, though 7075 has a tendency to flex a tiny bit, so depending on your surface finish requirements, may require a lighter finish pass. 7075 doesn't have the same corrosion resistance as compared to 6061 though. Hard anodizing parts takes care of the difference in wear characteristics between the two allows though :thumb:

If there is one kind of post that makes BF members "roll their eyes" more than any other, it's people who post telling others that they don't have to post or moreso NOT to post.

:rolleyes:

There....just did it.

Now who was it that said, "If you don't like people replying, don't start your damn thread on a public forum to begin with?"

Operator?
Al1943?
Retro Grouch?
Hillrider?
Jeff Wills?

...someone refresh my memory please!

:rolleyes:

...ooops did it again.

:rolleyes:

...damn mouse...

:innocent:

=8-)

Aluminum chain rings are always T6 heat treated.

I find the rest of your comment quite insulting, like suggesting I can't tell a used chain ring from a new one. Or suggesting that never checking the material specifications before purchase is a viable way of purchasing anything? How ludicrous is that?

I feel comfortable about putting you on ignore.

I'm quite comfortable with that as well. In fact, I don't really give a rat's A$#! No insult was intended and not EVERY alloy chain ring is made the same way or treated to the same processing specs. THAT much should be clear to you since you have had this disappointing experience that you shared.

Your statement that
"Sellers thrive on general ignorance. Heck, the in-built obsolescence of chain rings made of aluminum 6061 is a GOOD THING from their point of view, as you will be forced to buy a new chain ring much faster than if it were made of aluminum 7075 or better yet, steel." Is insulting to ALL sellers as a group. Do you honestly ASSUME that since you have had this experience and feel you were mislead or taken that every seller of components intentionally misleads the generally ignorant populace into buying parts that will wear out prematurely? If you really believe that, I'm sorry for you loss(sanity) The world is full of all sorts of people but primarily good ones. Some are unscrupulous but most are not and to jump to this conclusion is what is ludicrous. But that's also precisely why I said that I buy only from sources with solid reputations and a known return policy. That way I can pretend not to care about whether or not an item is made from 6061, 7075, 2024 or whatever. Don't lecture me on material specifications and knowledgeable purchases. I spent 25 years in the Aerospace materials business and am quite aware that not all aluminum is equal.

The posts questioning the value of the opening post are worth far less than the opening post.

The OP has relevance for some, while the naysayers pollute this board with their cynical wank.

If you think a thread isn't worth your time, don't answer it. Save the flames for those who really deserve them, and while you're at it, make it entertaining.

I'm quite comfortable with that as well. In fact, I don't really give a rat's A$#! No insult was intended and not EVERY alloy chain ring is made the same way or treated to the same processing specs. THAT much should be clear to you since you have had this disappointing experience that you shared.

Your statement that Is insulting to ALL sellers as a group. Do you honestly ASSUME that since you have had this experience and feel you were mislead or taken that every seller of components intentionally misleads the generally ignorant populace into buying parts that will wear out prematurely? If you really believe that, I'm sorry for you loss(sanity) The world is full of all sorts of people but primarily good ones. Some are unscrupulous but most are not and to jump to this conclusion is what is ludicrous. But that's also precisely why I said that I buy only from sources with solid reputations and a known return policy. That way I can pretend not to care about whether or not an item is made from 6061, 7075, 2024 or whatever. Don't lecture me on material specifications and knowledgeable purchases. I spent 25 years in the Aerospace materials business and am quite aware that not all aluminum is equal.

I was actually thinking the other day about how some states and municipalities actually have "contracts with minors" laws and codes supposedly intended to help minors becoming adults experience the "contract"...with an "out" of course. City of San Jose has one if I'm not mistaken...

I couldn't help but think of it when the OP first posted. Bottom line is though...I'm sticking to my original point - this really belonged in the "vendor review" forum as bulk of the original post was "vendor rant" oriented.

Hopefully the OP has learned something from all of it...

=8-)

Both grades pay the same at the scrap yard.

I've updated my post with the list of chainrings and their material specs. (http://www.bikeforums.net/showthread.php/755771-6061-aluminum-is-NOT-like-7075-aluminum.-They-re-not-even-ALMOST-similar!?p=13006062&viewfull=1#post13006062)

Not really because it left out a real important part.

Most parts are made of 6061-T6 aluminum. The T6 is a heat treatment that significantly affects the properties of the metal.

Correct. Also, I did not read the whole thread, how did the OP know the difference, a hardness test? Was it stamped?
Did he file it?

I've updated my post with the list of chainrings and their material specs. (http://www.bikeforums.net/showthread.php/755771-6061-aluminum-is-NOT-like-7075-aluminum.-They-re-not-even-ALMOST-similar!?p=13006062&viewfull=1#post13006062)

Why don't you start a more permanent and static webpage - as I have done with John Hurley's Spoke Head Identification Chart?

http://www.mrrabbit.net/docs/spokeheads/main.html

If you have SBC, Yahoo, ATT or Megapath/Speakeasy - chances are you have free disk space already to do exactly that.

Provide a tarball while you are at it so folks can download it and archive it for you...

=8-)

So, does that mean a 6061 frame has a little more flex and will absord vibrations on the road more than a 7075 frame?

I didn't make a vendor review, I made a short and hopefully clear explanation on the difference between two aluminum alloys often used for bicycle chainrings. I stated that aluminum 6061 is much easier to machine, but the chainrings made from it last much less.

What type of riding are you doing that makes this a compelling concern?

I'm still using 6061 chainrings on my bikes that are over 20 years old and have thousands and thousands of miles on them.

Correct,one you can weld and one you can't.

60 and 70 series make fine chainrings.Granted,70 series IS a much better ring,but 60 will last a long time on a bicycle if you maintain/change your chains.70 series is what ATV and motorcycle sprockets are made from,they need to last with much more power than most humans can put out(though sometimes I wonder with some of the claims made here at BF)

We can muddy the waters more and use 6061-T9,Now your approching 70 series strenght.T-9 temper is the same as T-6 except it is work hardened.

Your not going to find many 70 series frames unless they are glued together.70 series aluminum does not like to be welded,it's prone to cracking when welded.

So,in a perfect world,70 series chainrings and 60 series frames.

Your not going to find many 70 series frames unless they are glued together.70 series aluminum does not like to be welded,it's prone to cracking when welded.

If you're talking about 7075, yeah. But of course 7005 welded frames are extremely common and 7005 is proven to be a perfectly fine frame material.

7075 frames.......since that's what were talking about here.

Otherwise put a steel gear on it and call it a day.......

7075 frames.......since that's what were talking about here.

Seems like it would be easier to type "7075" than "70 series.";):D