wroomwroomoops

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.

wroomwroomoops

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.

milkbaby

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.

fietsbob

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..

HillRider

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.

wroomwroomoops

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.

I believe this is at least partially if not entirely due to the great difference in ductility between alumina and aluminum.

fietsbob

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

wroomwroomoops

Here is an example of why reducing ignorance is important: two reviews of Blackspire Epic chainrings.

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).

blamp28

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.

wroomwroomoops

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.

fietsbob

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

mrrabbit 

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.



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!



...ooops did it again.



...damn mouse...



=8-)

blamp28

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.

Kimmo

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.

mrrabbit 

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-)

dedhed

Both grades pay the same at the scrap yard.

wroomwroomoops

I've updated my post with the list of chainrings and their material specs.

2manybikes

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?

mrrabbit 

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

https://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-)

hybridbkrdr

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

JohnDThompson 

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.

Booger1

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.

well biked

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.

Booger1

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

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

well biked

Seems like it would be easier to type "7075" than "70 series."