Magnesium rims??

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Phill P
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by Phill P

I'm an engineer and I am always having crazy ideas....

I know American Classic made Magnesium rims, but don't seem to have them listed any more. I suspect they kept having issues with corrosion and erosion. AM also tends to make under weight products and I don't trust their durability (personal opinion...)

They only ever made road rim brake rims - why not MTB?
With the rise of road disc MG rims could be made without the need for a brake track - so less erosion and no longer exposing the Mg itself - the ano wouldn't wear.
Strikes me that are both mtb and road rims keep getting wider Mg rims could be a good intermediate step between Al and CF disc brake rims.

Does anybody know why AM no longer sells MG rims?
Does anybody know where AM got their Mg rims made?
Are the lower legs of suspension forks still made of Mg alloy? Nobody ever complained about suspension forks corroding....
Technical Director at www.TUFFcycle.com

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Marin
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by Marin

MTB folks don't complain. I have lowers with holes all the way through from corrosion.

Magnesium rims? We have carbon now :)

kulivontot
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by kulivontot

Pretty sure it has more to do with cheapo carbon wheels disintegrating the high end alloy clincher market than anything with durability.
I think the industry as a whole has kind of shifted away from the shallowest, lightest at all cost rims to more balanced semi-aero wider tubeless wheels.

Marin
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by Marin

Unfortunately the industry has shifted away from a weight focus - carbon rims have gotten heavier every year now.

chipomarc
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by chipomarc

Marin wrote:Unfortunately the industry has shifted away from a weight focus - carbon rims have gotten heavier every year now.


Not to worry about a couple hundred grams here and there.

Phill P
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by Phill P

Hmm I see everybody's point

The angle I was going for was intermediate performance and intermediate pricing.

If an Al rim costs say $5-10 to buy, but a CF rim costs $50-100 to buy, there is still room for something that costs $20.

I look on fairwheel and the cheapest Al rims they have are kinlins at $60-75 (normal price), but then they have many rim makes at $120+
Then the carbon rims (not Chinese/Taiwan rims) are $600-$1000

Seems there is plenty of opportunity to compete with a $100 retail Mg rim (if it could be made)
Technical Director at www.TUFFcycle.com

Phill P
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Joined: Sat Jun 02, 2007 1:10 am
Location: Nambucca, NSW, Australia
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by Phill P

Or maybe Scandium, wasn't Shimano using that as the base Al in the C24 rims?
but perhaps the wall thicknesses get a bit thin and hard to roll and keep a round rim. At least with Mg the walls would be a litter thicker.
Technical Director at www.TUFFcycle.com

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F45
Posts: 900
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by F45

With these complaints that carbon rims are too stiff, maybe there is a market.

But Mg is a bit soft, and a rim strike could ruin it.

You also run into corrosion issues. Often sealant and/or water will leak into the rim space.

You can call AC and ask them. Bill Shook seems like a gregarious fellow, often willing to talk and say some things that will make an engineer chuckle.

MikeD
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Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

Magnesium alloys don't have the strength and fatigue life that aluminum alloys do. No advantage. Kirk Precision made a magnesium frame. They all broke. Some guys at work made magnesium rims using extrusion dies used for aluminum. They all failed early, cracking at the spoke holes.

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pdlpsher1
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by pdlpsher1

I'm aware that Paketa still makes tandem bicycles out of magnesium. It's not high volume production but at least someone can still find a way to make it. I think given magnesium's vibration damping characteristic, a frame made from it could give an interesting ride.

Damping is a measure of the rate at which unforced vibration disappears, and is an intrinsic property of the material. Because magnesium has the highest known damping capacity of any structural metal – as much as 10 times greater than steel, titanium, or aluminum – the ride is truly amazing. Vibration from the road literally disappears within the structure of the frame and never reaches the rider. For this same reason, magnesium is used in the high-tech world of aerospace hardware; they have discovered that magnesium offers the best platform on which to mount sensitive electronic equipment, as it is so “quiet”.


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