Bicycle Mechanics - need info on magnesium bikes

Hi,

Does anyone know anything on the Magnesium bikes market? (how many were sold on 2001? is the market expected to grow?)
What technical (if any) problems should I expect with such bikes?


Thanx
sharon

Since magnesium is a b!tch to weld (it burns very easily, and the resulting fire is extremely hard to extinguish), and since it is so expensive, and actually weighs a bit more than titanium, I'd say the future for magnesium is quite limited.

What are the advantages of a magnesium frame, if any?

Corrosion is also an issue with using Magnesium.

What are the advantages of a magnesium frame, if any?

Well, for velo-poseurs that don't know squat about bikes, it sounds at least as cool as "titanium".

Advantages over titanium? None that I can see.

Over Aluminium or steel? Maybe a very slight weight reduction, but at a great cost.

The only places I've seen magnesium is in some of the shock forks, and somebody (sugino and IRD?) made cranks. The cranks had corrosion problems if I recall.

Kirk made cast Mg frames for an MTB in the late 1980s.
A few Eastern European ex aerospace companies make Mg tubed bikes.
Taiwan is getting into extruded Mg tubing, mainly as a marketing excecise.
Mg is a less dense than Al, so you can play with tube diameters and thickness to make an ultra-light sub 3lbs frame.
Just dont expect it to last.

This afternoon, I asked my friendly neighborhood materials engineering professor about magnesium vs. aluminum vs. titanium. His take is as follows:
Magnesium Pros and Cons:
20% lighter than aluminum for a given strength
Costs slightly less than titanium
Is only about 65% as stong/weight compared to titanium
Dangerous to weld or machine (see fire risk above)
Will corrode
Will react with steel bolts.

Interesting information, thanks d*alex! :)

when I was in boy scouts we used magnesium to help alond flint and steel. I know someone that has magnesium pegs on his bike and it saprks when he grinds, pretty cool.

http://www.firstflightbikes.com/KirkPrecision.html

Oh boy!!!!!!! I used to lust after these bikes when I was 14 years old.

They actually done a MTB for as low a price as £360. We used to sell them in Halfords years ago 1993.

Changing the direction of the thread somewhat...
I've heard that Titanium also burns. I don't intend to use my bike (or anyone elses) as a test case, but does anyone know how flammable it is, compared to magnesium?

Not nearly as combustible

Reason for a Mg bike... Escape vehicle! once you get away, set the bike on fire. the tubes would contain all the other chemicals you need to make thermite. just ride the bike across the bridge, then cut the bridge in half! GENIUS!!! :D

To D*Alex,
I hate to contradict you, but according to the periodic table of the elements, http://pearl1.lanl.gov/periodic/default.htm , Mg is Atomic Number 12 with an atomic weight of 24.305 while Ti is Atomic Number 22 with an atomic weight of 47.90 - in other words, titanium is twice as heavy as magnesium. In fact, Aluminum is Atomic Number 13 with an atomic weight of 27, making magnesium even lighter than aluminum. That, my friend is why they are trying to build frames out of it.

Originally posted by knifun
To D*Alex,
I hate to contradict you, but according to the periodic table of the elements, http://pearl1.lanl.gov/periodic/default.htm , Mg is Atomic Number 12 with an atomic weight of 24.305 while Ti is Atomic Number 22 with an atomic weight of 47.90 - in other words, titanium is twice as heavy as magnesium. In fact, Aluminum is Atomic Number 13 with an atomic weight of 27, making magnesium even lighter than aluminum. That, my friend is why they are trying to build frames out of it.

but aluminum and ti a probably less dense than mg. EVen if the atoms weigh is heavier

..As I responded to you in your private message, Knifun, what you fail to recognize is that these metals have widely different strengths. In actuality, for a frame of a given stiffness, titanium will be the lightest.
Also, magnesium burns when the metal reaches critical temperature, which is much lower than any of the other metals, and the easiest way to prevent this is by using thicker tubing than you might otherwise need.
Please, go to your local engineering school, and take a course called "material engineering", as well as one on strengths of materials. You chemistry lesson missed the point, and you did too.

DAlex,
Thanks for your quick materials lesson. Why then, if titanium is so much stronger than aluminum, are the pro frame builders using so much aluminum and only one or two using titanium. With your theory, ALL frames would be titanium - but that is not the case. Let me point out a FACT, the worlds lightest rideable bicycle is ALUMINUM, which is a material so much weaker than titanium. How can that be? Please see http://www.somec.com/guinness.htm where the complete bike weighs 4755 grams, or 10.473 pounds. With your theory, why did they not use titanium? You also forget one important fact my friend, that you can greatly increase the stiffness by using mulit-shaped tubing, but I forget, you are just reading out of a textbook, never using practical applications.

One other point, what does the ignition/flash point of magnesium have to do with bicycle racing? Is the rider going to go so fast that air friction ignites the frame? Why then is Mercedes using magnesium as their firewall material in their high end cars? This just doesn't make sense either? Titanium also burns at temps approaching magnesium. Have you ever seen a titanium fire? Have you ever seen titanium dust ignite? Its Bright blinding white.

Originally posted by knifun
One other point, what does the ignition/flash point of magnesium have to do with bicycle racing? Is the rider going to go so fast that air friction ignites the frame?

I would imagine the ignition/flash point probably has an impact in the construction of the frame...

I think the major reasons Aluminium is used more than Titanium is it's still cheaper, and I believe easier to weld.

Richard

There are still a very few making cool bikes out of Magnesium due to the great strength to weight ratio of mg.

http://www.litech-mg.ru/mountain.html
Currently producting mg bikes.

LodeStar also made some mg bikes a few years back. Arrow Bicycles and 3DRacing may have dabbled in Mg bike if I recall correctly, but my memory is a bit foggy on this.

I have also been told that Magnesium has very good vibration dampening properties to it. One of the engineer's or scientists out there can probably explain the reasoning for this technical, but from what I have heard, it is more desirable than titanium or aluminum for dampening of vibration. This is why Easton is now making steps out of mg.

I believe titanium has a springy-ness to it that is not as pronounced with magnesium. Aluminun is very stiff and doesn't allow much dampening at all to vibrations. Aluminum just transfers shocks. This is also one of the reasons titanium is selected over aluminum as preferred material for highend hard tails in many cases - due to it's dampening. Aluminum is cheaper for similiar weights however, and thus the trade off between costs vs properties & performance. On the flip side, if you have a shock in front and rear, Aluminum becomes the preferred choice because the shock is doing the dampening and thus make the frame stiff as possible to "track properly" without losing comfort. The shock does the dampening instead of the frame.

Corrosion is an issue for magnesium, and I don't believe it's an easy material to work with, which is why you don't see a lot of folks using it. Magnesium parts are almost always painted in some color, to protect against corrosion which happens quickly with magnesium. It is a highly reactive material if I recall correctly. (Easton switched the color of their mg stems recently from gold to black . . . this switch is likely due to better corrosion protection with the paint they are now using)

Rockshox has been using Magnesium for years as a material to build fork legs out of as far back as the Mag 21 for those who remember this old classic suspension fork.

Believe it or not Halfords are having a few magnesium models made for this year. I've not seen one yet but if I do I'll report back.

As I have said before, magnesium is a b!tch to work with. That alone will make it an expensive frame material.

Merida Taiwans second largest bike manufacturer and also one of the biggest in the world, who also make bikes for Specialized and a few others (hence they bought about 60% of Specialized over a year ago if not two years ago) are the first bike manufacturer in the world to perfect the manufacturing of Magnesium frame bikes. Their road bikes are the Merida Magnesium 907 and 909 series, both of these bikes are high end racers and are top quality bikes with top quality components. The 907 features Shim Ultegra groupset, where as the 909 features Shim Dura Ace group set. Apparently true magnesium is a very hard alloy to weld, so Merida invented this shot tube welding technology, also plus where the human hands failed to perfect this art of welding, the robots and computers did not, and their accuracy was perfect.

To see more go to www.merida.com

Or to see a picture of the 907 click on this link:

http://www.belimport.ch/cgi-bin/merida-db/openwindow?ArtCod=42107

Arguably the best BMX bikes ever created were made in the late 80's from HUTCH. The very best model had a magnesium frame and forks. As well as Magnesium hubs with Titanium axles.. These bike were super light and beautiful to ride. Magnesium is lighter and stronger than Titanium. The biggest benefit is that magnesium flexes. This is a major plus and the secret behind the beautiful smooth ride. Where the stiffness was needed such as the hubs than Titanium was used for the axles. Smart eh! I have been waiting for someone to start producing Magnesium frames again. Now the bad part. Yes the Magnesium Hutches did have a tenancy to crack. I'd still buy one and they are worth more today than they were new.
Hope this helps

dude, this thread is 7-YEARS OLD!!!

So, in another 10 or 12 years we can give it a proper education in metallurgy.
BTW, mag is a truly fascinating material.

Magnesium weighs .06 lb/cubic inch. Aluminum .1 lb/cubic inch. Titanium .16 lb/cubic inch. Steel .3 lb/cubic inch. Their relative stiffness is in the same order as their density. So in some shapes and designs one material can be lighter than any other of these materials. It all depends on the nature of the loads and any size or shape constraints. All of these materials have their pros and cons.

Sorry to confuse this discussion with facts....

I want a Magnesium Pinarello Dogma FPX

One other point, what does the ignition/flash point of magnesium have to do with bicycle racing? Is the rider going to go so fast that air friction ignites the frame? Why then is Mercedes using magnesium as their firewall material in their high end cars? This just doesn't make sense either? Titanium also burns at temps approaching magnesium. Have you ever seen a titanium fire? Have you ever seen titanium dust ignite? Its Bright blinding white.

And to add to that magnesium flaming up, why did Porsche introduce in 1973 a magnesium engine block in their Carrera RS 2.7? They didn't self ignite when the blocks got hot. They did have other problems with that material but catching fire was not one of them. I have a sneaky feeling that a magnesium bike frame would never get as hot as an engine block thus fire would not be one of my worries if I had a bike constructed of this material.

The engines more than likely had steel combustion liners with aluminiun heads.

Regards,
J T

And to add to that magnesium flaming up, why did Porsche introduce in 1973 a magnesium engine block in their Carrera RS 2.7? They didn't self ignite when the blocks got hot. They did have other problems with that material but catching fire was not one of them. I have a sneaky feeling that a magnesium bike frame would never get as hot as an engine block thus fire would not be one of my worries if I had a bike constructed of this material.

Magnesium doesn't ignite that easily-it takes a lot of temperature though once reached it goes like a bat out a Hellena. When there is a large piece of magnesium, the heat from an flame welder will be disipated over the whole metal suficiently that the kindling point is not reached.
Once magnesium fire starts, CO2 extinguishers and water can serve as oxidizers due the high affinity of the magnesium to oxygen. Magnesium fires will burn under water. Can be smothered with dirt.

I was in a race shop once when a magnesium fire started when an errant welding spark ignited magnesium shavings. It has an extremely bright white hot flame, hotter than welders. One person panicked and grabbed a CO2 extinguisher-I grabbed him before he fed the extinguisher's oxygen to the fire and reminded him it was a magnesium flame. We moved the contents out of the shop door and let it deplete itself. It melted a hole in the asphalt outside the shop.

Weld failures are the biggest problem. Magnesium weldings are often weak-though the Russians developed welding technology to make good magnesium bike frames. The magnesium is less corrosion resistant than other metals.

The magesium frame is stiff to low frequency flexing yet absorbes high frequency jars making it great for bumps while averting frame flex losses. Lighter than aluminum, slightly heavier than titanium, it is a lightweight frame material. If bent in an accident, it is more prone to cracking than other metals.

Magnesium doesn't ignite that easily-
The magesium frame is stiff to low frequency flexing yet absorbes high frequency jars making it great for bumps while averting frame flex losses. Lighter than aluminum, slightly heavier than titanium, it is a lightweight frame material. If bent in an accident, it is more prone to cracking than other metals.

That was my point, mag doesn't ignite that easily. Now I did see a Porsche mag engine catch fire once, reason for the initial fire I don't remember, but the block did light up and after the first fire trucks came on the scene they quickly realized that water wasn't going to work and had to call in a foam truck to smother it; of course by the time the foam truck came out the car was a total loss.

Personally I would not want a bike frame made of mag and not because it could catch fire, but more because it's expensive, it will crack instead of bend as you pointed out, and it is subject to corrosion.

I think it would be funny if someone had a bike made of mag and their house caught fire to see the looks on firemens faces trying to figure out why the bike was burning and putting off a bright white flame that water couldn't put out. Well the thought is funny, not that the actual event would be funny.

Lennard Zinn will will build a Mg bike:

http://www.zinncycles.com/road-mortirolo.php

Carbon fiber has beaten the alloys of Al., magnesium, Ti and steel. . It is lighter and stronger and does not fatigue.
The metal that could give carbon a run for it's money is berilium. The only problem is that it is expensive and the dust or vapor from welding and grinding is deadly.

About time for this thread to go back to sleep for another 7 years.

The engines more than likely had steel combustion liners with aluminiun heads.Porsche actually started experimenting with magnesium engine parts back in 1928. There were quite a few magnesium engines on their cars:

http://www.rennsportsystems.com/engines%202.7-3.2.html
http://www.azom.com/materials-video-details.asp?VidID=99
http://www.911turboregistry.com/history.html

Many '80s+ Porsche engines used Alusil blocks. This is a high-silicon content (+21%) aluminium alloy with low-expansion coefficient, making them more suitable for use with forged pistons than regular aluminium blocks. There is a couple of extra procedures in honing the cylinders. After the final dimensions are achieved, a special etching compound is used to remove the aluminium from between the silicon crystals. The result is an extremely hard and wear-resistant surface. It's not uncommon for rebuilds at 150-200k miles to not require any cylinder-prep at all. Just replace the rings, bearings, a valve-job and it's back on the road!

There were also many of these engines with Nikasil coatings on the alloy blocks. These suffered from corrosion issues (similar with BMWs) due to the higher sulfur-content of US gasoline.

Many '80s+ Porsche engines used Alusil blocks. This is a high-silicon content (+21%) aluminium alloy with low-expansion coefficient, making them more suitable for use with forged pistons than regular aluminium blocks. There is a couple of extra procedures in honing the cylinders. After the final dimensions are achieved, a special etching compound is used to remove the aluminium from between the silicon crystals. The result is an extremely hard and wear-resistant surface. It's not uncommon for rebuilds at 150-200k miles to not require any cylinder-prep at all. Just replace the rings, bearings, a valve-job and it's back on the road!


This sounds disturbingly like the original Chevrolet Vega engine which was anything but durable.

http://en.wikipedia.org/wiki/Chevrolet_Vega#Aluminum_engine_block

Carbon fiber has beaten the alloys of Al., magnesium, Ti and steel. . It is lighter and stronger and does not fatigue.
.

Fatigue? That's a bogus remark concerning any material. There's been steel bikes that have been riden over a million miles, let me know when you find a carbon frame with those kind of miles. And carbon stronger? That's a hoot as well, if you lay the bike down and put a small gouge in the frame it's so long carbon frame, whereas with any other material all you would of had was a scratch. And where are all the carbon fiber touring bikes? Funny all the other material you mentioned as inferior are all available for touring frames but not carbon. then of course with carbon you have the nasty little problem that if it is compromised and you don't know it, which has happened a lot, it will fail suddenly and rapidly without warning; with steel and ti that won't happen and you can ride it home even after you notice a problem.

Pinarello used to make the Dogma frame from Magnesium but has since switched over to Carbon starting from the beginning of 2009. Right now, the only frames being made out of Magnesium is by Paketa in the USA. The Paketa frames look pretty functional. Suntour has come out with a compact crankset as well as a 130 BCD Magnesium crankset that looks pretty sweet for 2010.

Seemed to me that some years ago a couple of Russian aerospace firms were turning out protoype Beryllium frames. Another exotic and difficult-to-weld metal....Wonder whatever happened to that?

Pinarello used to make the Dogma frame from Magnesium but has since switched over to Carbon starting from the beginning of 2009. Right now, the only frames being made out of Magnesium is by Paketa in the USA. The Paketa frames look pretty functional. Suntour has come out with a compact crankset as well as a 130 BCD Magnesium crankset that looks pretty sweet for 2010.Paketa thread over in the Tandem forum:
http://www.bikeforums.net/showthread.php?t=594272

They didn't like my comment about fatigue very much - probably ill-advised anyway.

Magnesium has been used as a lightweight material for a long time. "Back when" some Mag Wheels were actually magnesium-probably an alloy of course, but mainly magnesium.Now Mag Wheels are aluminum usually.

For most practical purposes-units of goodness per unit of cost it is hard to beat aluminum or steel.But then a practical person only needs one bike, and lotta folks have more than one bike, so no claims to practically here.

Since magnesium is a b!tch to weld (it burns very easily, and the resulting fire is extremely hard to extinguish), and since it is so expensive, and actually weighs a bit more than titanium, I'd say the future for magnesium is quite limited.
According to the 1972 American Welding Society Handbook, Volumn 4 Magnesium and its alloys are weldable. The GTAW process is usually the best way to do it. It is most likely easier to weld than Titainium because Ti. requires an inert atmosphere until the temp drops below about 850 degrees F.

Fatigue? That's a bogus remark concerning any material. There's been steel bikes that have been riden over a million miles, let me know when you find a carbon frame with those kind of miles. And carbon stronger? That's a hoot as well, if you lay the bike down and put a small gouge in the frame it's so long carbon frame, whereas with any other material all you would of had was a scratch. And where are all the carbon fiber touring bikes? Funny all the other material you mentioned as inferior are all available for touring frames but not carbon. then of course with carbon you have the nasty little problem that if it is compromised and you don't know it, which has happened a lot, it will fail suddenly and rapidly without warning; with steel and ti that won't happen and you can ride it home even after you notice a problem.
Who makes a Magnesium touring frame? How many Ti touring frames are on the market? Aluminum can fail catastrophically.
Specialized makes this bike with a carbon fork that is designed for fenders and racks that can be used a a touring bike.
The falacy in your arguement is that there are so few touring bikes made that there is no one willing to make one from carbon.

Actually aluminum powder is very flammable also. There is a product called Thermite which is a mixture of powdered aluminum and iron oxide. When lit (by a magnesium ribbon igniter) the aluminum "burns" by extracting the oxygen from the iron oxide and the tremendous combustion heat melts the now free iron. This stuff is used to do field welding repairs and was often used to repair cracked railroad tracks.

Who makes a Magnesium touring frame? How many Ti touring frames are on the market? Aluminum can fail catastrophically.
Specialized makes this bike with a carbon fork that is designed for fenders and racks that can be used a a touring bike.
The falacy in your arguement is that there are so few touring bikes made that there is no one willing to make one from carbon.

That's ridiculous. Look at Trek, they make lots of CF bikes. What do they choose for the frame material of their touring model? Steel. If Trek thought CF would be a good material for a touring frame they would make it. Jamis, Fuji and many others as well. CF simply is not as durable as steel or Ti or even Alum. for a touring bike frame. I'm talking real world durability, not lab test theory. To say that CF has beaten the alloys of the other metals is a crock.




About time for this thread to go back to sleep for another 7 years.

+100

Porsche actually started experimenting with magnesium engine parts back in 1928. There were quite a few magnesium engines on their cars:

http://www.rennsportsystems.com/engines%202.7-3.2.html
http://www.azom.com/materials-video-details.asp?VidID=99
http://www.911turboregistry.com/history.html

Many '80s+ Porsche engines used Alusil blocks. This is a high-silicon content (+21%) aluminium alloy with low-expansion coefficient, making them more suitable for use with forged pistons than regular aluminium blocks. There is a couple of extra procedures in honing the cylinders. After the final dimensions are achieved, a special etching compound is used to remove the aluminium from between the silicon crystals. The result is an extremely hard and wear-resistant surface. It's not uncommon for rebuilds at 150-200k miles to not require any cylinder-prep at all. Just replace the rings, bearings, a valve-job and it's back on the road!

There were also many of these engines with Nikasil coatings on the alloy blocks. These suffered from corrosion issues (similar with BMWs) due to the higher sulfur-content of US gasoline.

Interesting you quoted Rennsport Sytems but failed to catch what they said about magnesium engine blocks Porsche used, and their problems that require extensive-read that as expensive-machine work to make them reliable for rebuild; plus pulled head studs and main bearing bore distortion from excess heat and cylinder heads warped and valve guides needed replacement within 50K miles. It was always cheaper to replace the mag block with a AL block then it was to try to get the mag block to work right. I don't care how long Porsche used magnesium, it was obvious that from 1928 to 1977 they learned nothing about the metal. In 1978 Porsche gave up on the mag blocks and went with AL and had extreme good
luck with that series of engines.

This sounds disturbingly like the original Chevrolet Vega engine which was anything but durable.

http://en.wikipedia.org/wiki/Chevrolet_Vega#Aluminum_engine_block

The car you pulled into the service station to have the attendant fill up the oil and check the gas. :crash:

Interestingly, the same technology was used in the 494 Can Am engine the Team McLaren cars were using at the same time, and the aluminum cylinder engines would keep going through the end of the race even when the enging had lost its oil. Of course those were only 200 mile races, maybe they would have seized in another hundred miles.

Oddly enough, Kent has recently been making a couple of magnesium folders. Who'da thought Kent would use exotic materials on something. They were advertising the light weight on those folders.