Road car Steel Wheel weights vs Road car Alloy wheel weights

[Smokes]

Hi I have started to notice this style of steell wheel becoming more common with OEMs
http://www.fordpartsuk.com/shop/ford_f ... _c_388.htm
I am just wondering how much lighter are these than the cheap cast alloy which tend to be heavier than steels as they have to add more material in a cast alloy to make the me stronger.
Even though audis basic alloy wheel was a forged item
http://www.fuchsfelge.com/index.php?id=83&L=1

I am also wondering if these type steel wheel are stiff enough for track use as that would give a bigger handling improvement over the weak alloys

[Greg Locock]

Run away Brave Sir Robin. A styled steel wheel will be more compliant than a disc type steel wheel. It may be stiffer or lighter than a cheap alloy, I don't know about that specifically, I'd guess that 16x6.5 is getting close to the point where alloys are lighter than steels. It will be more robust than the alloy, as you can kerb it with greater gusto.

Basically in engineering if it looks kewl then a more boring looking version of the same thing will usually perform better objectively.

[tathan]

I thought they used that style so they can stick a spoked hubcap on and it still looks alloy-ish.

Steels are normally lighter than alloys except for expensive competition/motorsport wheels - I used to have 16" forged SSRs that were 6-odd kg each, mega light for a road car. The normal Halfrauds line-up though are heeeavy.

Problem with using steels is there is very little over 16", and the only 16" I know of is a VW one. Most are 13/14/15 which isn't much good for a track as you have to then have milk bottle tops for brakes.

[Tommy Cookers]

IIRC a steel wheel will never be as true as one would like
a cast alloy wheel, being machined to profile internally and in the centre bore, should be round, concentric and without lateral runout
some were/are ? not
cast wheels can appear out of round at the flange, but be true where it matters (on the bead seat)

as with tyres, the price will cover the cost of those rejected as out of tolerance
so quality (tight tolerances) is not cheap
rejects too often find their way onto the market

after this I found that weight seemed less important

[Smokes]

Sterling distort due to the welding but I doubt it alloys are easier to buckle hence why the are heavier. Cast wheels have the rim profile rolled to shape if I remember correctly. Matching would be a waste of material and time and would cause the material to crack. With regards to brakes what wrong with ducting them properly using race pads and brake fluid with braid hoses. As long as you keep the steel brakes cool they should not fade. And cheaper than fitting heavier discs
.

[kaiyara]

Wow. You do not see a new engine design every day (unless you happen to be a fan of our esteemed member, Feliks).

Thanks a lot, roost89, very nice video.

[MOWOG]

The general marketplace does not care. It demands 18+ inch alloys. Volkswagen does offer a very attractive "retro" steel wheel with hubcap on its new New Beetle, but again, that is there due to styling and marketing decisions rather than engineering requirements.

I notice when I take my Miata to track days that most of the serious racers run on 13" wheels, because they offer the lowest combined tire and wheel weights, and on a Miata, unsprung weight is critical. And I would point out that F1 runs 13" wheels and is able to stuff brakes inside them that generate up to 5 g's of stopping force. If you require more than 5 g's on your street car, you are very stout street racer indeed!

[neilbah]

in the past steels were fitted to base models which meant skinny widths and not a lot of tyre choice. a lot of guys i know use banded steels to overcome that limitation

[Edis]

Sterling distort due to the welding but I doubt it alloys are easier to buckle hence why the are heavier. Cast wheels have the rim profile rolled to shape if I remember correctly. Matching would be a waste of material and time and would cause the material to crack. With regards to brakes what wrong with ducting them properly using race pads and brake fluid with braid hoses. As long as you keep the steel brakes cool they should not fade. And cheaper than fitting heavier discs
.

Cast alloy wheels are cast and then machined round, and to be able to cast them you need a certain wall thickness, that's why cheap alloys can be heavier than steel wheels. Steel wheels are roll formed from sheet steel and then welded, a steel wheel hence have a very low thickness which will give a lower weight at the cost of stiffness. Aluminum alloys designed for casting are also not as strong as those designed for forging, but unless the steel wheel is made from some higher strength grade I would suspect the strength to be about comparable. But the alloys used for casting is probably not as ductile as mild steel, which is why they tend to crack rather than buckle.

More expensive wheels are usually forged and then machined. The forged alloy is stronger and more extensive machining means the weight can be kept down.

The general marketplace does not care. It demands 18+ inch alloys. Volkswagen does offer a very attractive "retro" steel wheel with hubcap on its new New Beetle, but again, that is there due to styling and marketing decisions rather than engineering requirements.

I notice when I take my Miata to track days that most of the serious racers run on 13" wheels, because they offer the lowest combined tire and wheel weights, and on a Miata, unsprung weight is critical. And I would point out that F1 runs 13" wheels and is able to stuff brakes inside them that generate up to 5 g's of stopping force. If you require more than 5 g's on your street car, you are very stout street racer indeed!

F1 runs 13" wheels because that is what the regulation demands.

That they can reach 5G during braking is due to aerodynamic drag (1G) and the excellent grip due to high downforce. Since a car is very lightweight, and since part of the energy is lost as drag you can make do with some very small carbon/carbon brakes given that the brakes use forced cooling. This is very different to what you find among street cars.