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Hey everyone:welcome:
so here goes another dumb question, what exactly is the difference between Mag Wheels and Convetional Wheels?
All I know is that they are magnesium or somethin', but what are advantages to mag wheels? Are they lighter? Easy to clean?

Just asking,



Mike
 

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I thought at one time "Mag" did refer to magnesium alloy wheels but eventually became a broader slang term to include custom wheels of pretty much all types...that's how its used where I'm from anyways.

Magnesium metal was lighter than the traditional steel wheels at the time. Density of around 1.74g/ cubic cm (pure magnesium) vs. 7.87g/ cubic cm for steel. The move to magnesium alloy was a big weight saver, however as mention below in the following post Aluminum came on the scene.

Shrug...someone correct me if I'm wrong :spank:
 

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Originally "Mag" wheels were cast from magnesium. Then the custom wheel makers started to cast the same wheels in aluminum, much cheaper. The term "Mag" wheel stuck. Al tho most are really aluminum. A real set of "Magnesium" rims will cost a young fortune and are very touchy about being polished constantly and they tarnish very easily.

Conventional wheels are cast/forged of aluminum or pressed in steel or a combination of the two. Most are plated or coated to reduce wheel maintenance.
 

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Magnesium is an elemental metal like iron, aluminum, and sodium. On the other hand steel and stainless steel are technically compounds of elements yielding an alloy metal of certain desired properties.

"Mag" wheels were originally cast from basically pure magnesium way back in the early years of automobiles. If you have seen those great blue Bugatti's from the early 30s with the wide spoked 21" or so wheels , those are magnesium castings. Magnesium's main desirable characteristic is light weight. It is 15% less dense than aluminum and 58% less dense than iron(steel). That is about the only good quality though. Otherwise it is more brittle and can crack and fail without warning is almost impossible to weld sine it will spontaneously ignite at temperatures much lower than welding temperatures, and is extremely reactive, reacting with atmospheric oxygen and water vapor causing severe pitting. It is almost impossible to keep a polished finish so most users let it go to it's natural state. It has a molecular weight of 12 and is only one step up on the periodic table from sodium metal. Sodium is so reactive that it must be stored in a non-aqueous liquid to prevent contact with water. If a piece of sodium is dropped into a container of water it bursts into a bright white flame you cannot look at. Magnesium fires like sodium ones cannot be quenched with water, they are accelerated by it so the only way to put out a magnesium fire is by smothering it. Ask me some time about the little fire I started on my dad's wood shop floor by lighting some magnesium metal shavings I gathered from making slot car racing frames and piled onto an aluminum plate!

The term "mag" has a special meaning in hot rodding circles. As stated above, in the early 50s it began to be applied to hot rod style wheels made from actual magnesium metal. as hot rodders gradually migrated to aluminum versions of the same wheel styles, the term went with them, thus it has become the slang term for a style of wheel rather than being a true technical term.

Here is a photo of an aluminum "mag" (5-spoker on the car), and a true 60s real "mag". The finish on each wheel is true - the mag quickly reverts to that oxidized surface in only a couple of months if not continuously polished. Aluminum is a great substitute - not that much heavier, easy to weld and machine, ductile so won't crack, not nearly as reactive so will hold a finish indefinitely with a little care.

 

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Tranny fluid. Those hydros are famous for the fluid coupling check valve failing (not if, but when) which allows the fluid to drain from the huge fluid coupling can back into the tranny. Fluid level builds up until it is as high as the rear output shaft and slowly drips out the weep hole in the tranny drive shaft yoke. Only happens if the car sits for more than 2 or 3 days w/o starting. I bought a 1 1/4" wide strip of 16ga sheet metal to install in the pan for enough spare volume so the fluid level won't ever build that high. Just need to get the time to cut the pan in half, weld in the strip, lengthen the pickup tubes and dip stick and get the pan re-chromed. All it takes is time and money!
 

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Real mags are relatively rare nowadays. They are out there but not being made anymore as far as I know. There are a lot of aluminum versions being made of hundreds of designs, few of which are exact duplicates of the great old originals. A notable exception is the ones shown on the front of my car below. These are EXACT aluminum duplicates of the Halibrand 'Gasser" front wheels that virtually all of the big named guys ran in the 60s. Almost impossible to find in original magnesium, these aluminum versions were mad by Dom Waldron, Rods West, and are a god-send to us gasser lovers. The rear slotted real mags shown in the above post will complete my set of real gasser wheels.


 

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A better, more correct term for newer wheels is "alloys". I'd kinda like to see the term "mag" reserved for the real thing so it means something.
 

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Ok, my "alloy" wheels, American Racing are polished, or were until they were left outside over winter & now have small white blems all over which I guess are tiny pits. So, I've tried mild cut polish & silvo but after rubbing small spots for an hour or so & getting little results, I'm frustrated. does anyone have a way & or product to speed things up?
 

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Hi,
Anyone know what the outer material is on the early wheels that have a steel rim back side??
These wheels were out in the 60's and were heavy also,usually with painted spokes.
Thanks,lumpy65
 

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I believe the most current term for "mag" is any wheel that uses a shoulder type of nut to center the wheel onto the hub.

I don't know if Cragar developed the "universal" wheel but it was very popular in the 80's with their "SS" model.
 

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So the follow-up question is:

If you were running REAL magnesium wheels, could you generate enough heat (say if you had a blowout and the wheel rubbed the asphalt, or if a driveline component went belly up and the wheel were to rub a steel half-shaft/U-joint) to set the wheel "ablaze." :pain:
 

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I do think mag, that is true magnesium-based alloy, wheels are still being made. They are however, quite expensive. Some of the C5 Corvettes (about 10% in 1999 for instance) came equipped with wheels, cast in Italy, that were supposedly real magnesium. The set of four was a $3K option over the standard aluminum alloy wheels that most early C5s were equipped with. I think this same Italian company also make wheels for some of the European exotica. FWIW-the wheels have the word "magnesium" painted (or maybe silk screened) on the rim.

PatM
 

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I have an early set of wheels that have a steel wheel back but an outer lip that is dull and won,t polish
like wheels made later.They must be very fragile because there is a metal backing under the front lip of
the rim.The 5 spokes are painted semi gloss black.The mounting caution is from Cragar Wheel co.
Any ideas about how old these are?


elkay65
 

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I have an early set of wheels that have a steel wheel back but an outer lip that is dull and won,t polish
like wheels made later.They must be very fragile because there is a metal backing under the front lip of
the rim.The 5 spokes are painted semi gloss black.The mounting caution is from Cragar Wheel co.
Any ideas about how old these are?


elkay65
If the front looks like a mag wheel w/ no steel rim showing the insert is aluminum. They made these in the 60s and 70s as a low cost alternative to magnesium or solid cast aluminum. They cast steel lugs in the aluminum insert so they could weld that to the steel rim. They should polish like aluminum, may have so much oxidation you will need to sand them with several grits before polishing step.
 

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Mag wheels

Yesterday I had questions about how old some mag wheels are ,so here are some pictures.
Notice the steel bead behind the outer edge of the outer lip.The back side is a steel rim.
I tried sanding the outer lip but it does not seem to really shine.??
elkay65
 

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Yesterday I had questions about how old some mag wheels are ,so here are some pictures.
Notice the steel bead behind the outer edge of the outer lip.The back side is a steel rim.
I tried sanding the outer lip but it does not seem to really shine.??
elkay65
Yes those are the same wheels I described in the post above. That aluminum should polish up. There are pretty deep machined scratches that will need to b sanded out with progressively finer sand paper until you have it smooth with 1000grit. Then you can go to the tripoli then white rouge bugging wheels and get a mirror finish.
 
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