4130 Chromoly vs. Reynolds 853 Steel

[Bobinator]

Can any of you explain the diffrence between the various steels used for bicycles and their
comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It
seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance.

 

[R2D2]

853 has a higher strength to weight ratio, has better fatigue strength and stiffness (about 30% greater than 4130). 853 is still Reynold's best steel. The joints actually gain strength as they cool. 853 cannot be brazed, only welded.

Reynolds makes a 4130 called Reynolds 525. It's a general all-purpose tube - less expensive than 853.

R2

Originally posted by Bobinator
Can any of you explain the diffrence between the various steels used for bicycles and their
comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame. It
seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance.

 

[Rorschandt]

[email protected] (Bobinator) wrote in news:[email protected]:

> Can any of you explain the diffrence between the various steels used for bicycles and their
> comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame.
> It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance.
>

IIRC,most Reynolds steels use manganese as the stiffening alloy, although they do make a 4130. 4130
uses chromium and molybdenum. Butted tubing is more difficult to come across in larger diameters and
lengths that are most oft used in bents. Straight gauge 4130 is readily available.Also, many alloys
have more stringent temperature restrictions for brazing or welding. 4130 is more forgiving than
most. Reynolds 853 is recommended to be used with lugged construction silver brazed methods.
Recumbent lugs are a bit difficult to find.(^: Here is more info on the subject, written by people
who know much more than I:

A good description of Reynolds tubings: http://www.worldclasscycles.com/JACKSON-HOME.htm and
http://www.desperadocycles.com/The_Lowdown_On_Tubing/About_Steel_Tubing_pag
e4.htm

and http://www.henryjames.com/tubing.html and http://www.phred.org/~josh/build/brazing.html and
http://www.waterfordbikes.com/models/const.php

happy trails, rorschandt

 

[Mark Stonich]

rorschandt <[email protected]> wrote in message news:

> Reynolds 853 is recommended to be used with lugged construction silver brazed methods.

DEFINITELY NOT!!!! See; http://www.reynoldsusa.com/prop/853.html where you will see that silver
brazing is on Reynolds' list of "Tips on what you MUST NOT do with Reynolds 853"

R2D2 <[email protected]> wrote in message news:<[email protected]>...

> 853 has a higher strength to weight ratio, has better fatigue strength and stiffness (about 30%
> greater than 4130).

Within a tiny range, all steels are equally stiff. Alloying and heat treating affect fatigue,
tensile and yeild strength. Not the modulous of elasticity.

> 853 cannot be brazed, only welded.

853 can be brazed with brass or bronze, with or without lugs, as long as it is heated to at least
850 C (1560 F). This is pretty much a given, as most brass or bronze alloys melt at about 1620F.

 

[S. Delaire \"Ro]

The reason recumbents are done in 4130 is that a the tubing shapes and sizes of a diamond frame bike
do not cross over to a recumbent... yet. Diamond frame tubes are usually no longer then 2 feet. Some
recumbent frames require 4 foot lengths. Diamond frames are fairly routine in their dimensions. In
many cases, paint is all that makes one brand different from another. In recumbent land the frames
are very different from one maker to the next. Change the paint and you will still know where the
frame came from. 4130 is good, strong material that comes in many sizes and shapes. Perfect for the
small manufacture. Speedy

Bobinator wrote:

> Can any of you explain the diffrence between the various steels used for bicycles and their
> comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame.
> It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance.

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[Rorschandt]

[email protected] (Mark Stonich) wrote in
news:[email protected]:

> rorschandt <[email protected]> wrote in message news:
>
>> Reynolds 853 is recommended to be used with lugged construction silver brazed methods.
>
> DEFINITELY NOT!!!! See; http://www.reynoldsusa.com/prop/853.html where you will see that silver
> brazing is on Reynolds' list of "Tips on what you MUST NOT do with Reynolds 853"

Can't really argue with the Reynolds website! I don't know where I got the silver part(sorry!), but
the rest is just quoting from the Bob Jackson website: "The main advantage of Reynolds 853 is its
ability to air harden after joining, a characteristic not shown by other chrome molybdenum /
manganese molybdenum materials presently on the market. When building frames using either TIG
welding or high temperature brazing, above 1600 degrees, the joints increase in strength as the
frame cools to room temperature.

LUG CONSTRUCTION IS THE PREFERRED METHOD OF JOINING 853. It allows a much larger area to be heated
than tig welding which concentrates the heat to a very small area at the weld. This completely goes
against the “AIR HARDENING” building philosophy of the material and adds nothing to the strength of
the joint. It is however a much cheaper joining method, requiring less time and skill to perform."

I'm unlikely to be using the stuff myself. For now, 4130 crmo and 6061 and 7000 series aluminums
serve my purposes fine. I have used chunks of heat hardening steels for other machined parts, not on
frames. I wonder how they control the distortions in a "air hardened" tube?

rorschandt

 

[Royg]

FWIW, interesting comment I saw posted recently on steel tubing:

"725 is Reynold's replacement for 753, it was introduced 4-5 years ago. It is a Chromium-Molybedenum
steel alloy that is heat-treated. Its non heat-treated brother is 525 which is also the 531
replacement. 725 is a very desirable tubing, said to be nearly identical to the famous but sadly
gone Tange Prestige tubing. Biggest advantage versus 753 is its heat tolerance. Its low carbon
content makes 725 easily joined with silver, brass or even TIG welding, although it does suffer some
annealing in heat effected area. Most importantly for ride and durability, 725 has much better
elongation and ductility than air-hardened alloys thus maintains much of that resilience that
tubesets like 531 and 753 were most noted for. I would avoid 853/653, Columbus Foco/Ultra Foco,
Dedacciai 16.5 and True Temper OX Platinum/Gold -- these are in my experience rather "harsh or
brittle" to borrow your phrasing."

"Bobinator" <[email protected]> wrote in message
news:[email protected]...
> Can any of you explain the diffrence between the various steels used for bicycles and their
> comparitive advantages? Example: A Lemond Zurich (DF) boasts a Reynolds 853 sticker on the frame.
> It seems as though all of the steel recumbents are 4130 chromoly. Thanks in advance.

 

[Dave Larrington]

FWIW the frame of the late lamented Kingcycle was made from custom-ovalised plain-gauge 531.

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Jim Plaia]

General rules of metallurgy: Stiffness is a function of elastic modulus. Just about all steel alloys
have similar enough moduli that any difference would vanish into the noise.

One should almost NEVER weld heat treatable steels, or any other heat treatable alloy for that
matter, unless you are prepared to re-heat treat or accept the loss of strength in the base metal
next to the weld joint. The weld may meet the strength of the original base metal but the heat from
the welding will completely mess up the heat treatment of the base metal next to the joint.
Furthermore in thick sections, nothing in bike manufacture is thick enough for this concern, it is
required to heat the metal to red hot to prevent cracking of the base metal next to the weld joint.
(Personal lesson learned here is to never simply tell someone to get the joint hotter than hell
before welding unless you tell them how hot you think hell
is.)

Fatigue resistance and actual tensile strength is a function of the alloy, but it is also a function
of the heat treatment. Also, the fatigue resistance of steels is relatively high. Minor changes can
seriously affect the fatigue properties of aluminum alloys because it is is much lower, but steel is
relatively tolerant. I'm not sure if you'll see any real differences here in a practical, rather
than laboratory, situation.

If there is any real differences, you might see some effect in corrosion resistance. An alloy that
is tweaked to the limits of what it can do will corrode faster than one that is working in the
center of its capabilities.

4130 Cr-Mo steel is used frequently because it is an old well-characterized alloy. It's commonly
available, easy to manufacture, and in the kinds of section thicknesses you see in bikes, easy to
heat treat. If you were willing to pay what it cost to make a custom titanium bike and end up with a
steel bike, I could suggest some better steel alloys that, if you were the kind of rider that
Fabrizio thinks he is, you might be able to detect the difference in performance.

From a basic metallurgy standpoint only, the differences in alloys means they can charge you more
money because they use their "custom" alloy rather than garden variety 4130. Racing strips would be
about as effective.

 

[R2D2]

Mark is correct that 853 tubes can be Manganese-Bronze/Copper brazed (RBCuZn Type, between 866-882 degrees C). I should have stated that you should not use some of the more common silver brazing methods (low temp) on tube joints (silver brazing or soldering can still be used for cable stops and other "braze-ons" though).

853 has a much higher Ultimate Tensile Strength than 4130. Typically 190 KSI vs. around 120 KSI (about 50% greater).

853 has a strength to weight ratio close to Ti!

Because the air-hardened joints Increase in strength after welding, the overall stiffness of the frame is increased substantially (30% greater than 4130 Chrome-Moly is typical). I'm talking about a built frame here, not raw tubes. This is of course due to the fact that the 4130 joints will become annealed during the joining process. Now some may argue that the ride of a frame built with un-heat treated steel is much more forgiving (softer), and thus preferable.

I'm not saying that an 853 frame is ultra-stiff by any means. My aluminum DF Klein MTB would be considered ultra-stiff. Klein heat treats the entire frame post welding. The energy transfer from pedal to wheel is simply amazing.

Quote from ReynoldsUSA site: "Fatigue life on framesets will be appreciably higher than conventional Chrome-Mo frames."
This is good news for everybody.
http://www.reynoldsusa.com/indexb.html

Jim's advice here pertains to un-heat treated tubes (like the 4130s), and not the heat-treated 853. Take a Zurich out for a test ride (it was the last DF that I bought), and you'll see what a great ride it has. The 853 is truly a superior steel. I love LeMond's fit and cockpit philosophy too.

Check out Harris' website for more good info on welding and brazing:
http://www.jwharris.com/home/

Hope this info helps some,
R2

Originally posted by Jim Plaia
General rules of metallurgy:

 

[Tom Sherman]

R2D2 wrote:
> ... Because the air-hardened joints Increase in strength after welding, the overall stiffness of
> the frame is increased substantially (30% greater than 4130 Chrome-Moly is typical). I'm talking
> about a built frame here, not raw tubes. This is of course due to the fact that the 4130 joints
> will become annealed during the joining process. Now some may argue that the ride of a frame built
> with un-heat treated steel is much more forgiving (softer), and thus preferable.

The increase in strength at the joints will not effect elastic modulus significantly. You are
confusing two different things here. It would take precision equipment to measure the difference in
elastic modulus between Reynolds 853 (before or after heat treatment) and 4130 Cro-Moly. In
practical terms there is no difference.

> I'm not saying that an 853 frame is ultra-stiff by any means. My aluminum DF Klein MTB would be
> considered ultra-stiff. Klein heat treats the entire frame post welding. The energy transfer from
> pedal to wheel is simply amazing.

This has to do with the size and wall thickness of the tubing and the frame geometry - heat treating
the frame after welding affects tensile strength but not elastic modulus.

> Jim's advice here pertains to un-heat treated tubes (like the 4130s), and not the
> heat-treated 853....

Jim is correct about there being no appreciable difference in the elastic modulus of the two steels.

Tom Sherman - Quad Cities USA (Illinois side)

 

[Jim Plaia]

First before I say anything, I've just had knee surgery to correct a problem with my knee that's
prevented me from cycling for about 10 years and I'm only on the newsgroup because my wife's about
to buy a Streetmachine. Now that I've admitted to having no credentials at all about frame building,
discussions on this this newsgroup seem to imply that the frame performance is mostly based on
stiffness. Once the frame is strong enough to deal with the abuse life throws at it, a stronger
frame is unimportant. The stiffer a frame gets the more cycler power can be applied more efficiently
(I realize that there was a discussion about having too stiff a frame).

If I'm correct about that, frame stiffness is again a function of modulus and does not include
tensile strength at all. All steels from 1020 plain carbon steel to the special through harndening
tool steels have close enough moduli that you day to day variation in cycling will swamp the small
change in cycling performance. Tensile strength is only important when that cyclist hits a
bump/curb/car/etc and it's time to decide how badly the bike gets bent.

Second question, titanium and aluminum are rarely selected because of their strength to weight
ratios. They tend to be cited for their excellent stiffness to weight ratios. If you are not
constrained in tube thickness, titanium or aluminum alloys can match the stiffness of a steel bike
with a fraction of the weight. The also tend to have tend to have shorter fatigue lives and fun
corrosion modes (if it's fun for the metallurgist, it's not fun for the user). Saying that a steel
has the same strength to weight ratio as titanium is nice, but I still think that stiffness(modulus)
is the driving property and there isn't a steel in existence that matches aluminum or titanium in
modulus to weight ratio.

I'm probably not going to change anyone's mind, but I'll give the official metallurgy party line:
Don't weld heat treatable steels without giving them a post-weld heat treatment or understanding
the loss of strength caused by welding. The base metal isn't simply annealed. The base metal has
melted next to the weld joint (melting the base metal is the definition of welding rather than
brazing). That metal has now converted to martensite; really strong and really brittle. The base
metal that didn't melt but is next to the weld is fully annealed and likely to be dead soft for the
base metal. The area that didn't get fully annealed is over-tempered and much weaker then it should
be, and so on out from the weld until you reach unaffected base metal. There are ways to get a
mechanically reinforced joint so this doesn't matter, but welding on a heat treated steels is
generally a bad idea.

 

[R2D2]

Several frame builders use this same quote in describing the advantages of 853 over typical 4130:


"Reynolds 853 when introduced in 1995, set new standards for steel bicycle tubing. The strength to weight ratio of 853 is equal to that of quality titanium frames.

Normal chrome molybdenum steel will lose strength in the joints after welding, 853 actually increases in strength as the frame. This unique air hardening property of Reynolds 853 provides additional stiffness through reduced micro yielding at the joints, allowing stiffer frames with excellent fatigue strength (when compared to standard chrome molybdenum) and excellent ride quality."


They are describing stiffness (modulus), NOT Ultimate Tensile Strength, .2% Proof, Fatigue limit, or % Elongation!

I also realize that the primary increase in the stiffness of my Klein is due to tube diameter, and the radical forming of the tubes & stays that Gary employs, but having stronger joints also increases the overall stiffness of the frame (as a whole).

Take the flexing of the bottom bracket area on a typical bike built of 4130. This shell is a tube of huge diameter compared to its length - an 800 lb gorilla would have a hard time bending this piece. In addition, the screwed-in bottom bracket itself works to increase its strength. The flexing is actually being done at and near the joints. Now a frame built of 853 WILL be stiffer at these joints due to its air-hardening properties, allowing less energy to be wasted in bending metal.

Like I said before, just go out and ride some of these bikes. You'll see what various frame materials can do for a bike. I just wish that Reynolds would draw some tubes in 2 1/2" and 3" diameter for us 'bent riders (and be affordable).

Not that I would have the confidenced to build a frame from 853 myself. I'll stick with Reynolds 525 to suit my meager abilities.
R2

 

[Mark Stonich]

[email protected] (Jim Plaia) wrote in
> If I'm correct about that, frame stiffness is again a function of modulus and does not include
> tensile strength at all.

The desirable types of stiffness in a bike frame come from increasing rigidity in bending and
torsion. These increase rapidly with increases in diameter. Higher tensile strength steels allow
higher diameter to wall thickness ratios. OX Platinum is available in
1.375" diameter that is only 0.016" thick between the butts. In 4130 such a tube would dent or
buckle too easily to be practical.

> there isn't a steel in existence that matches aluminum or titanium in modulus to weight ratio.

Steel and Aluminum have almost identical modulus to weight ratios. Steel's is pretty constant.
Aluminums have some variation but the average is about the same as steel. Titanium lags well behind
at about 87% of steel. Aluminum will build a stiffer frame for a given weight, only because you can
use larger diameters.

Example; If an aluminum tube has a 20% larger OD can have walls twice as thick as a steel one, for
dent and buckling resistance, and still be 11% stiffer yet weigh only 82% as much.

If OD is constrained, steel wins, as the extra bulk of the aluminum is closer to the middle of the
tube where it is less effective.

Don't get me wrong, I've no desire to move into exotic steels, Al, CF or Ti. I built a 4130 frame
with a 60" wb that weighs 4.5lbs. and is stiff as granite against pedalling forces, yet nicely
compliant vertically. An Al frame with this much vertical flex would fail rather soon IMHO.

BTW True Temper has found that their non-air hardening, heat treated steels retained a higher
percentage of their strength after welding than their non-HT tubes.

 

[R2D2]

Kudos Mark on the great frame!

My attempt at a 66" LWB weighed in at a full 6 lbs. I have nowhere near enough experience to start pushing wall thicknesses or shaping. I guess I'll just keep being conservative until I can find a Mentor.

I agree, vertical compliance is a pretty high priority with these babies.
R2

Originally posted by Mark Stonich
Don't get me wrong, I've no desire to move into exotic steels, Al, CF or Ti. I built a 4130 frame
with a 60" wb that weighs 4.5lbs. and is stiff as granite against pedalling forces, yet nicely
compliant vertically. An Al frame with this much vertical flex would fail rather soon IMHO. [/B]

 

[Mark Stonich]

R2D2 <[email protected]> wrote in message news

>This unique air hardening property of Reynolds 853 provides additional stiffness through reduced
>micro yielding at the joints, allowing stiffer frames with excellent fatigue strength (when
>compared to standard chrome molybdenum) and excellent ride quality."

Well that settles it then. Alloying and heat treatment CAN alter the modulous of elasticity of
steel. This sentence, written by some advertizing flack, ovbiously disproves the results of more
than 200 years of metallurgical science and many, many thousands of tests. Just think of all the
textbooks that will have to be re-written. The implications for spring design alone are enormous.

 

[R2D2]

Point well made guys.
Thanks for persevering (darn advertising hacks!)

R2