Classic & Vintage - 1020-2040 steel

Just curious about these two, was 1020 or 2040 indicative of a particular brand, or a generic reference to a production process? And, is there much difference in the two? What brought this up is that I have a Motobecane Mirage that is 1020, and just found out that my daughter picked up a Super Mirage for me that is made of 2040 steel. She paid 2 bucks for it!

$2?!?!??!?!??!?!??!

I wish I could find a Super Mirage for $2!

The numbers reflect the ratios of the metals in the steel alloy, although I can't remember off the top of my head what they are. Both hi-tensile steel.

I just tried to google it, because I remember reading something negative about one of them-- the 2040 I think-- but couldn't find it.

Found it. It's in BF, but the search function is disabled, so here's the quote from the archives, without a link:


the frame material varies on Grand Touring bikes, from Reynolds 531 on the very best, through Vitus tubing (arguably about as good) to the execrable "high resiliency" 2040. I haven't seen any examples of 1020 tubing showing up in the GT's but it's even softer and heavier than 2040.

1020 Steel (http://www.suppliersonline.com/Research/Property/metals/819.asp)

I can't find a similar page for 2040, but it's apparent that 1020 is a carbon steel alloy, and 2040 is apparently a lighter steel alloy. I'm sure there's a thread in BF somewhere that explains the differences between steels. For example, Carbolite is a high carbon steel, possibly situated above 1020 and 2040? Also, I've seen a thread explaining the difference between gaspipe and hi-ten (I used to think they were the same thing, but apparently they're not?). Unfortunately, the search function is temporarily disabled again....

[QUOTE=Blue Order]$2?!?!??!?!??!?!??!

I wish I could find a Super Mirage for $2!

I have a fairly extensive network of purchasing agents that are always on the lookout. If they see skinny tires or drop bars, they call.
http://i9.photobucket.com/albums/a57/crazy-b/DSC02443.jpg
http://i9.photobucket.com/albums/a57/crazy-b/DSC02445.jpg
http://i9.photobucket.com/albums/a57/crazy-b/DSC02444.jpg
http://i9.photobucket.com/albums/a57/crazy-b/DSC02445.jpg

I have a fairly extensive network of purchasing agents that are always on the lookout. If they see skinny tires or drop bars, they call.

I have a somewhat different system: the two guys at the dump call me if anything with QR hubs comes in. If I take the bike, they get a six-pack. But only one sixer per visit. I've come away with four decent (but not great) bikes for the price of a rack of Rolling Rock.
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1020 Steel (http://www.suppliersonline.com/Research/Property/metals/819.asp)

I can't find a similar page for 2040, but it's apparent that 1020 is a carbon steel alloy, and 2040 is apparently a lighter steel alloy.
Not quite right...

All steel alloys weigh the same, for the same amount of material, but better quality alloys are stronger.

With stronger steels, you can build bikes out of thinner tubing, so the tubing and the bikes are lighter, even though the steel has the same specific gravity.

When dealing with structures, strength and weight are interchangeable qualities.

Sheldon "I Don't Know The Difference Between 1020 And 2040 Either" Brown

D'OH! Of course! Stronger steel alloy = thinner tubing = lighter tubing. D'OH!

And...

Whoa! Corrected by Sheldon "I Don't Know The Difference Between 1020 And 2040 Either" Brown to boot! Made my day! :D

One half of the numbers is the amount of carbon in the steel, and the other is the strength in thousands of PSI. I don't remember which one is which. I'll check my daughter's welding book when she gets home from school.

Granted, they aren't chrome-moly, Reynolds 531 or Columbus tubing, but they truly are not "bad" tubes. The frames will be a bit heavier, be less sought after by collectors, and have slightly different feels to them, but they still will ride nicely.

Granted, they aren't chrome-moly, Reynolds 531 or Columbus tubing, but they truly are not "bad" tubes. The frames will be a bit heavier, be less sought after by collectors, and have slightly different feels to them, but they still will ride nicely.

It seems that most everything on 27x11/4 tires rides well. I have a late 80's Bianchi Brava made of double butted Ishiwata tubing riding on 700x20 tires, and any of my old school Schwinns have a smoother less jarring ride.

Motobecane used 1020 on the entry level models during the 1970s boom. Sometime around 1977-1978 they switched to 2040. In general, 2XXX numbers denote nickel steels. That is assuming its a valid AISI-SAE designation. I wouldn't put it past the marketers to just double the old numbers, to make the consumer think that the new tubing is twice as good.

The real proof in the pudding is to measure the thickness of the tubing walls. The easiest way is compare seat post sizes on the bicycles made of 1020 and 2040. The frame with the smaller seat post size should have the thicker walls and weaker tubing. Of course there is a potential pitfall in this method. The early 1020 tubes may use the old, 28mm outer diameter, French standard, seat tube, while the newer, 2040 models may use the 28.6mm outer diameter, English/Italian seat tube. In which case, you'll just have to measure the outer diameter of the seat tube too.

1020 and 2040 are both SAE (Society of Automotive Engineers) designations for mild carbon steel. The first two digits indicate the series (amounts of mangenese, silicon, copper, nickel) and the last two indicate the quantity of carbon (hundredths of a percent -- so 1020 would have about .20% carbon). Both designation are long out of date and are not used much anymore -- steel buyers now purchase their grades to exact spefications for dozens of alloys, not just carbon-manganese-silicon. The mill I used to work at sold about 300+ grades of steel, and I can't ever remember referring to SAE grades. 2040 would be a "better" steel than 1020, but still nowhere near the strength/weight ratio of chrome-moly (4130 or 4340 for instance).

BTW, an excellent source for metallurgy and steelmaking is Carrol Smith's "Engineer to Win". If my copy wasn't buried in my basement I'd have a better answer for you.

Secondskin, while I aggree with most of your post, I have to respectfully disagree with you on a couple of points. Under the AISI/SAE system, the 2xxx series was designated for nickel steels. While all steels are alloys, the 2xxx series has a high enough nickel content to justify it own alloy class and distinguish it from plain carbon steels. While 2040 may not be in the class of chromium-molybdenum steels, calling it a carbon steel is a misnomer.

Technically, chromium-molybdenum steels are restricted to the 41xx series. 4340 is a nickel-chromium-molybdenum steel.

All steel alloys weigh the same, for the same amount of material, but better quality alloys are stronger.

With stronger steels, you can build bikes out of thinner tubing, so the tubing and the bikes are lighter, even though the steel has the same specific gravity.Just to clarify Sheldon's statement some more, "stronger" does not mean "stiffer". A thinner-walled high tensile steel tube is just as strong as a thicker-walled mild steel tube in that they both fail under the same load. However, the high tensile steel tube is less stiff; it will bend more before it buckles. What this means is that a frame built from thinner, higher quality steel tubes will be just as "strong" and a cheap "gas pipe" frame, but it will be lighter and springier, while the gas pipe frame will be heavier and deader. Of course, then there are special applications such as track frames, which could be built from heavier gauge alloy steel to be stronger and stiffer than a road frame.

I have a somewhat different system: the two guys at the dump call me if anything with QR hubs comes in. If I take the bike, they get a six-pack. But only one sixer per visit. I've come away with four decent (but not great) bikes for the price of a rack of Rolling Rock.
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Yeah, but are going toget the same kind of service once they realize what Anhauser-Busch is doing with Rolling Rock?

Syke
Deranged Few M/C

Yeah, but are going toget the same kind of service once they realize what Anhauser-Busch is doing with Rolling Rock?



In fact, it might work to my advantage, as this is Bud country.
Very sad about Rolling Rock:mad: . Got my first serious buzz with it about age 14 and been drinking it ever since:) ; I'm a sucker for the green silkscreened long-neck bottles.
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(it's Sepetember, time to switch to Geary's)

"I'm a sucker for the green silkscreened long-neck bottles."

Back in college, more years ago than I care to think about, I used to drink Rolling Rock for the same reason.

"I'm a sucker for the green silkscreened long-neck bottles."

Back in college, more years ago than I care to think about, I used to drink Rolling Rock for the same reason.

I'm originally from Johnstown - lived about 20 miles from the plant. I'm LIVID about what's happening to the brand. Anhauser-Busch is on a lifelong ban from my house.

Syke
Deranged Few M/C

I'm originally from Johnstown - lived about 20 miles from the plant. I'm LIVID about what's happening to the brand. Anhauser-Busch is on a lifelong ban from my house.

Syke
Deranged Few M/C

Ok, what did they do?

Sounds like they're going to have to change the ad slogan... ;)

Secondskin, while I aggree with most of your post, I have to respectfully disagree with you on a couple of points. Under the AISI/SAE system, the 2xxx series was designated for nickel steels. While all steels are alloys, the 2xxx series has a high enough nickel content to justify it own alloy class and distinguish it from plain carbon steels. While 2040 may not be in the class of chromium-molybdenum steels, calling it a carbon steel is a misnomer.

Technically, chromium-molybdenum steels are restricted to the 41xx series. 4340 is a nickel-chromium-molybdenum steel.

About 2040 being a mild steel, I was a little loose with my wording. Calling 4340 a chrome-moly steel is not misleading at all however, especially to the layperson, as it is a chrome-moly steel with a higher nickel content. As I'm sure you know, 4340 is often used in the same applications as 4130 -- 4130 being used where weldability is critical, 4340 for ultimate fatigue strength.

Now we can get back to the beer discussion.....steel and Rolling Rock in the same thread....someone here must be from Pittsburgh!