Hi guys, I'm after some info on Casting Magnesium vs Aluminium for wheels. If you have read my M20 build log you will see I'm making a lot of my own Die's for Uprights, bellhousings, Trans Cases, and Wheels. I have been told by the foundry I used for my Uprights that They can do Magnesium for my wheels after I expressed concern at the estimated weight of aluminium wheels They say its 2/3rds the weight but could cost as much as 5 times the price. Has anybody had experience with this and what were the draw backs?? is it really that much more expensive?? Does it need heat treating after?? and Is it stronger ??? any help would be apreciated. Cheers Leonmac.
Magnesium vs Aluminium Wheels
- Thread starter leonmac
- Start date
Hey Leon,
Very light for sure, tends to corrode fairly easily, mag is very strong for the weight, it tends to have a life span. So many hours and they start to develop stress cracks. At least that is the way it worked on my Marchesini motorcycle wheels. I know your molds are already made but I would be conservative and cast them with a little extra beef if going mag. Perhaps having someone do a computer stress analysis using your molds cast with mag would help make the final desision.
I picked up a ferrari F1 wheel of recent manufacture...I swear it did not weigh more than 2 pounds. Stunning.
Hope youre not too bored out there!
Very light for sure, tends to corrode fairly easily, mag is very strong for the weight, it tends to have a life span. So many hours and they start to develop stress cracks. At least that is the way it worked on my Marchesini motorcycle wheels. I know your molds are already made but I would be conservative and cast them with a little extra beef if going mag. Perhaps having someone do a computer stress analysis using your molds cast with mag would help make the final desision.
I picked up a ferrari F1 wheel of recent manufacture...I swear it did not weigh more than 2 pounds. Stunning.
Hope youre not too bored out there!
Cost vs. weight savings isn't really worth it unless you've got tons sponsor $$$ to dump into a racecar. Besides the point that an uncoated Mag takes alot of care, ages rather poorly, reacts with water and air negatively.
All in all just not worth it IMO.
If you did mag you should run off a number of sets. There is a market for them.
Crosswiate and Gardner in the UK are making magnesium wheels for original GT40s,
And I had the opportunity to lift a rear with a Goodyear Blue Streak on it. Scary light! I am used to hauling the aluminum SPF wheels with street tire around. I almosy fell over when I bent over and lifted....no resistance! Again, mag has a poor life on the street with rain, salt and other nasty stuff.
If you decide to go with the Magnesium Leon I think you could extend the life considerably by painting them with a suitable paint, I used to have a paint/preparation procedure here for the Jongbloed wheels of the TVR, but lost it in a computer meltdown....pain in the butt if you ever need to crack test later on, but then again the correct type of paint [ hard, non flexible ] in a lighter colour should give a good indication if a crack occurs in service
Or just have them coated with Dow 1 or 9 , gold or black finish...standard for Mag.
The newer Mag alloys dont corrode anywhere near as badly as they used to..
I have some samples from a local company,that have a nice machined finish on the wheel lip and they have not dulled in the last couple of years..
The newer Mag alloys dont corrode anywhere near as badly as they used to..
I have some samples from a local company,that have a nice machined finish on the wheel lip and they have not dulled in the last couple of years..
Thanks guys for your input, I would like to go Mag but I think it will come down to Cost, I have priced a set of M8F wheels from Vintage Engineering and to be honest they were reasonable if you are in the states but to expensive to have shipped out here. If I was to have a bunch run off I don't think I could compete with them in the US and here I would only have a very small market, A few F5000 guys Maybe. The thing is the foundry guys are real keen to do them and have said we need to talk about it. So watch this space. Cheers Leonmac.
Ron Earp
Admin
If you're not a professional race team, ie, getting paid to race for money or have big sponsors, I don't think it makes a lot of sense to go Mg.
If you go standard casting process Mag is the way to achieve light wheels.
Current BBS 3 piece racing wheels are using a forged aluminium center cnc machined and is even lighter than their previous "cast only" version without the hassle of mag.
THere are also a variaty of mag/aluminium alloys where wheels are made from. My racebike has TECHNOMAGNESIA wheels on it which are said to be made out of such alloy. they don´t corrode compared to the old campagnolo mags i have.
TOM
Current BBS 3 piece racing wheels are using a forged aluminium center cnc machined and is even lighter than their previous "cast only" version without the hassle of mag.
THere are also a variaty of mag/aluminium alloys where wheels are made from. My racebike has TECHNOMAGNESIA wheels on it which are said to be made out of such alloy. they don´t corrode compared to the old campagnolo mags i have.
TOM
Tom, We have a company here in NZ www.arrowwheels.co.nz that do Very high quality spun 3 piece wheels and I have spoken to them in the past about using their shells and my centre (Having a meeting when I get home) it would be a lighter opion, I just can't pull myself away from the original look just yet.
Ron, I hear you mate, the cost is certanly alot more than I expected, But I would ask, If I were to make these parts availible for sale would it make a difference??? thats the $10,000 question. I'm thinking more the uprights, bellhousings, Trans casing. Cheers Leonmac.
Ron, I hear you mate, the cost is certanly alot more than I expected, But I would ask, If I were to make these parts availible for sale would it make a difference??? thats the $10,000 question. I'm thinking more the uprights, bellhousings, Trans casing. Cheers Leonmac.
It really boils down to a matter of what it will cost.
If outright performance is your goal then magnesium is the way to go.
As a guide, a typical 17 x 11 magnesium wheel for a V8 Supercar weighs around 9.0 kg whereas the same size wheel made from aluminium would weigh around 13.5 kg. This is a saving of 18 kg of vehicle weight, but more importantly, it is a substantial saving in the unsprung weight which will substantially improve your vehicle ride and handling performance. (I don’t know if they still do it, but F1 cars used to use specially lightened magnesium wheels with 3 mm thin wall section to further reduce unsprung weight just for qualifying and then discard them after each qualifying session.)
The cost of a magnesium casting should not be five times the price of an aluminium casting. Whilst there is a little more care and attention required for melting and casting magnesium it should only reflect no more than 1.5 to 2 times the cost of an aluminium casting. Also, magnesium machines very well (providing you don’t use a blunt tool and start a fire in the shavings!!!) and therefore machining should cost around the same as for aluminium.
Corrosion is not much of a problem these days. Older wheels were typically cast in AZ91A , AZ91B or AZ91C and these did suffer from corrosion problems. However the newer AZ91D and AZ91E alloys are much purer and more corrosion resistant. Also, a (Dow) chromate or an (AnoMag) anodized finish will give additional protection. Preferably don’t paint your wheels as this will hide any fatigue cracking if it starts to occur and you will need to completely remove any paint to do any dye penetrant crack inspection (which you should do – particularly if it’s a new untried design.)
Structurally there is not much difference between a similar wheel design in either aluminium or magnesium but a T4 heat treatment is definitely recommended as this will improve the mechanical properties of AZ91.
Hope this helps….
Hi Leon
I have been searching for about 2 years to find someone or company that have a high standard on casting wheel center. As I intend to cast my wheel using one or three pieces rim. I saw a good casting by accident last year at Swap met. He told me that the person did it for him was from Nelson. Hopefully I will met him again this year during the swap met in Christchurch. Have you try Gavin Bateman from 41° RACING WHEEL (Wellington) he makes some Saker wheels.
I have been following your build thread, and found it very interesting and challenging for what you have achieved.
LIM
I have been searching for about 2 years to find someone or company that have a high standard on casting wheel center. As I intend to cast my wheel using one or three pieces rim. I saw a good casting by accident last year at Swap met. He told me that the person did it for him was from Nelson. Hopefully I will met him again this year during the swap met in Christchurch. Have you try Gavin Bateman from 41° RACING WHEEL (Wellington) he makes some Saker wheels.
I have been following your build thread, and found it very interesting and challenging for what you have achieved.
LIM