Magnesium bike?
10-30-14, 06:32 PM
#1
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10-30-14, 07:02 PM
#2
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I am not at all knowledgeable about magnesium or the brand, but $1,000 seems awfully high for a dinged 8 year old bike with 105.
10-30-14, 07:39 PM
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Ever drop magnesium in water in chemistry class at school? I don't think a bike made of magnesium is a good idea.
10-30-14, 07:49 PM
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I think they're mostly aluminum, but I'm not a materials expert by any means.
10-30-14, 09:05 PM
#7
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The Paketa website says the material is "92% magnesium, alloyed with other metals to achieve optimal mechanical properties while facilitating the extrusion and welding processes."
In his series "Metallurgy for Cyclists" written in the 1990s, Scot Nicol (founder of Ibis) had this to say about magnesium as a frame material.
I think I'd pass.
In his series "Metallurgy for Cyclists" written in the 1990s, Scot Nicol (founder of Ibis) had this to say about magnesium as a frame material.
Originally Posted by Scot Nicol
Magnesium
Imagine a metal with half the density of aluminum, strength better than 6061, and elongation around 10 to 11 percent. I'm describing a magnesium alloy here, currently being tested by Easton. While magnesium is not normally known for its ductility, Easton says the material looks promising with those 10 to 11 percent elongation numbers. Although the modulus is low, in the range of 6MSI, that really shouldn't be an insurmountable problem. Aluminum has a relatively low modulus, but it doesn't mean an aluminum frame can't be built stiff. The same will hold true for magnesium, in fact a lower modulus would be welcome in the eyes of many.
One issue that needs to be addressed with this metal is the extreme problem with corrosion. Leave a magnesium part out in the rain and it will disappear faster than just about anything except unpainted steel. This problem can be overcome with proper surface treatment, like painting or anodization.
One of the intangible benefits of magnesium is that if you need to start a fire for some reason, just scrape some flakes off your dropouts, and light them up. They'll easily burn. For the mini- Hindenburg effect, just add water. The oxygen and hydrogen in the water disassociate, and party down with help from the magnesium. By the way, titanium does the same thing, but it's a little harder to get it started.
Imagine a metal with half the density of aluminum, strength better than 6061, and elongation around 10 to 11 percent. I'm describing a magnesium alloy here, currently being tested by Easton. While magnesium is not normally known for its ductility, Easton says the material looks promising with those 10 to 11 percent elongation numbers. Although the modulus is low, in the range of 6MSI, that really shouldn't be an insurmountable problem. Aluminum has a relatively low modulus, but it doesn't mean an aluminum frame can't be built stiff. The same will hold true for magnesium, in fact a lower modulus would be welcome in the eyes of many.
One issue that needs to be addressed with this metal is the extreme problem with corrosion. Leave a magnesium part out in the rain and it will disappear faster than just about anything except unpainted steel. This problem can be overcome with proper surface treatment, like painting or anodization.
One of the intangible benefits of magnesium is that if you need to start a fire for some reason, just scrape some flakes off your dropouts, and light them up. They'll easily burn. For the mini- Hindenburg effect, just add water. The oxygen and hydrogen in the water disassociate, and party down with help from the magnesium. By the way, titanium does the same thing, but it's a little harder to get it started.
10-31-14, 08:26 AM
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This is likely the best known of the bikes marketed as a Magnesium frame, but I think lots of bikes were built with some kind of magnesium alloyed tubes. I always assumed Bianchis mangalloy stays had some percentage of magnesium in them. Wonder how many more times I can get magnesium in this reply to a post about magnesium? 
I do agree the bike the OP links to is way over priced. It is likely only rare because that is the only one the seller has ever seen out in Hooterville.
Kirk Precision. These were a cast magnesium (one more) and were targeted at the TriGeek market in the late '80s.
I do agree the bike the OP links to is way over priced. It is likely only rare because that is the only one the seller has ever seen out in Hooterville.
Kirk Precision. These were a cast magnesium (one more) and were targeted at the TriGeek market in the late '80s.
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10-31-14, 09:47 AM
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I am impressed that they found a way to weld even a magnesium alloy. It has been done, I know. Mercedes at LeMans comes to mind and the Porsche 917/30 allegedly had a magnesium sub frame which no one would admit to because of the LeMans Crash that had the Mercedes fly into the grand stand to horrific results.
10-31-14, 09:55 AM
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Pinarello Dogmas were magnesium up until the 2009 model year, except for the carbon seatstay and fork. In 2010 the Dogma went all carbon.
$5500 MSRP if you'd like to buy one NOS. Most distributors have marked them down to $4500 now.
Not saying a Paketa is a Dogma, but Magnesium is difficult & expensive to work with. That's why you don't see many of them, and [my guess] no more new production into the future.
$5500 MSRP if you'd like to buy one NOS. Most distributors have marked them down to $4500 now.
Not saying a Paketa is a Dogma, but Magnesium is difficult & expensive to work with. That's why you don't see many of them, and [my guess] no more new production into the future.
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Last edited by Ex Pres; 10-31-14 at 11:30 AM.
10-31-14, 10:22 PM
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10-31-14, 11:04 PM
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I am impressed that they found a way to weld even a magnesium alloy. It has been done, I know. Mercedes at LeMans comes to mind and the Porsche 917/30 allegedly had a magnesium sub frame which no one would admit to because of the LeMans Crash that had the Mercedes fly into the grand stand to horrific results.
11-01-14, 05:35 AM
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I owned one of the magnesium Pinarello Dogmas and it's an amazing bike. Crazy fast, very smooth riding, top notch in almost every way. Almost, it seemed to have premature BB shell corrosion from water/sweat collecting where the FD cable wrapped around the BB shell...it was heavy. When I bought it has already been ridden heavily by the previous owner, my guesstimate is that it had upwards of 50,000 miles on the clock.
For $1000-1200 there are a lot of nice name brand bikes out there....wait until the weeks before Christmas.
11-03-14, 09:44 AM
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The 'mang' in mangalloy comes from manganese.
11-04-14, 10:33 AM
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Not bad considering I am not 'smithy' nor trained in the arts of metallurgy!!
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Last edited by Bianchigirll; 11-04-14 at 01:15 PM.
11-04-14, 12:09 PM
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11-04-14, 01:21 PM
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Well since no one else posted it. Personally I don't think the bike looks all that expensive, check out that seat post binder bolt.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
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Last edited by Bianchigirll; 11-04-14 at 01:26 PM.
01-10-21, 06:31 PM
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+1. And for a no name bike it makes it even less the deal.
I owned one of the magnesium Pinarello Dogmas and it's an amazing bike. Crazy fast, very smooth riding, top notch in almost every way. Almost, it seemed to have premature BB shell corrosion from water/sweat collecting where the FD cable wrapped around the BB shell...it was heavy. When I bought it has already been ridden heavily by the previous owner, my guesstimate is that it had upwards of 50,000 miles on the clock.
For $1000-1200 there are a lot of nice name brand bikes out there....wait until the weeks before Christmas.
I owned one of the magnesium Pinarello Dogmas and it's an amazing bike. Crazy fast, very smooth riding, top notch in almost every way. Almost, it seemed to have premature BB shell corrosion from water/sweat collecting where the FD cable wrapped around the BB shell...it was heavy. When I bought it has already been ridden heavily by the previous owner, my guesstimate is that it had upwards of 50,000 miles on the clock.
For $1000-1200 there are a lot of nice name brand bikes out there....wait until the weeks before Christmas.
