Non-steel wheels.

I think I read somewhere, and I'm not sure where it was, that for Redline's purposes you perform this equation for wheel inertia:

32 X wheel width X wheel radius

then if it's a non-steel wheel you multiply either by 0.7 for alloy wheels, and 0.5 for carbon fiber, but I haven't found any information for aluminum wheels. I have taken this wild guess...

7.85g/cm3 for steel

2.7g/cm3 for aluminum

So the ratio for Redline would be....

2.7/7.85=0.34394904459

The cars I've tried with setting are quite stable, abnormally so, in fact, but they understeer, they're a bit sluggish to brake (shouldn't the opposite be the case????!!!), and then the worst problem is also the most obvious...... The weight of a wheel isn't just the rim, but all of the unsprung weight, basically the rim, the rotor, the caliper and other brake fittings, the tire, and the air. Therefore....I'm assuming my equation is wrong. Does anybody have something more refined?????

I too used the 0.5, but it does cause problems. I believe the Z06.R and C6.R handling problems come partly from this.

PS: Carbon fibre is about half the density of aluminum - if CF is 0.5, Aluminum isn't 0.4.

NoNameBrand wrote:I too used the 0.5, but it does cause problems. I believe the Z06.R and C6.R handling problems come partly from this.

PS: Carbon fibre is about half the density of aluminum - if CF is 0.5, Aluminum isn't 0.4.

Maybe the alloy figure of 0.7?????? I'm not sure what "alloy" means, exactly...

As far as I remember is alloy a mix of materials, one of which is a metal. In the automotive industry it might be aluminum with zinc (one of many aluminium alloys).
Steel is also an alloy, its main component being iron.
Aluminum alone is too soft to be used alone.
So when you write that alloy is 0.7 of steel, in excel terms that would be a circular reference
Inertia is not only weight dependant, also the distance of the mass (for example the rim bed) to the rotational center is important. So a larger aluminium rim might have the same inertia as a smaller steel rim, depending on the size difference (given the same total wheel diameter).
In my testing I found that going below 0.7 of Giles' formula has negative effects on braking, suspension setup and steering response.

Wikipedia has this article.

As I understand it, the constituent elements in an alloy are always metals - Tomte, perhaps you are thinking of composites.

Here is a nice table of data for you to chew on.

Battlewagon wrote:I'm not sure what "alloy" means, exactly...

Alloy wheels refers to any wheel made out of a lighter-than-but-strong-as-steel alloy. An alloy, is as dj described, a mixture of two metals.

I guess I meant to say that at least one of a minimum of two materials must be a metal. At least this is the definition I also found on Wikipedia. What exactly is the difference to a composite I cannot say right now (composite: at least two different materials?).
Anyway, I just find it misleading just to speak of alloy wheels, because every car that doesn't use wood, stone or carbon wheels has 'alloys'.

Tomte wrote:every car that doesn't use wood, stone or carbon wheels has 'alloys'.

... now there's an idea.

djpimley wrote:

Tomte wrote:every car that doesn't use wood, stone or carbon wheels has 'alloys'.

... now there's an idea.

Back to the stone age!!!