Rims Weight

[yener]

I'm wondering;

Let's say a rim weights 5kg. 4 times 5 makes 20kg all together.
The minimum weight of a car including the driver, fluids and on-board cameras is 640KG. Including the rims.

Lets say a team makes 2 kind of rims. One set with 5 kg a rim and another set with 2 kg a rim.

Now when entering parc ferme at the end of the Quali they need to use the heavy rims to get to their minimum weight. They also start the race with the heavy ones. But after the first pitstop they can change to the lighter rims which make them run 12KG lighter then legal.
At some track this could be worth at least 0,2 seconds a lap.

Is their any control of the FIA ?

[FoxHound]

I believe that the rims are only dimensionally regulated:

Front 305-355mm; rear 365-380mm

However, you do have a very good point in that lighter rims could potentially be used to lighten the car during stints.
But there is a caveat.

Why would a team run heavier mass on all four corners of the car when it could be lighter? The more central and lower the mass is, the better.
So if a team is using heavier rims during qualy, and lighter rims during stints.... it's to paper over cracks in their initial calculations of their concept or possible issues with fuel consumption/mass(they may run heavier alloys at the end to be legal).

So my guess is, they would run the lightest possible alloy at all times.

[Lycoming]

not to mention less unsprung mass.

I agree, It would be preferable to just run the lightest rim all the time. It's better to carry weight as ballast, especially when it lets you get weight off the corners. You would also have to switch back to the heavy rim for your last stint, because they will inspect everything in post race parc ferme. So, you're compromising two stints so you can drop a chunk of weight for one stint. I wouldn't bother.

Also, I get the feeling that somebody would notice this sooner or later. Pirelli mounts all the tires, and I get the feeling somebody would notice that 1 set of rims from a team ways more than double the other set from the same team.

[strad]

And just how would they make this light set of wheels?

12.3 Wheel material :
Wheels must be made from AZ70 or AZ80 magnesium alloys.
12.4 Wheel dimensions :
12.4.1 Complete wheel width must lie between 305mm and 355mm when fitted to the front of the car and between 365mm and 380mm when fitted to the rear.
12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when fitted with wet weather tyres.
12.4.3 Complete wheel width and diameter will be measured horizontally at axle height, with the wheel held in a vertical position and when fitted with new tyres inflated to 1.4 bar.
12.4.4 Wheel dimensions and geometry must comply with the following specifications :
- The minimum wheel thickness is 3.0mm.
- The minimum bead thickness is 4.0mm (measured from hump to outer edge of the lip).
- The ETRTO standard bead profile is prescribed.
- The tyre mounting widths are 12” (304.8mm +/-0.5mm) front; 13.7” (348.0mm +/-0.5mm) rear.
- The wheel lip thickness is 9mm (+/-1mm).
- The outer lip diameter is 358mm (+/-1mm).
- A lip recess of maximum 1.0mm depth between a radius of 165mm and a radius of 173mm from wheel axis is permitted (for wheel branding, logo, part number, etc).
- With the exception of the wheel lip, only a single turned profile with a maximum thickness of 8mm is allowed radially outboard of the exclusion zones specified in Article 12.4.5.
- The design of the wheel must meet the general requirements of the tyre supplier for the mounting and dismounting of tyres including allowance for sensors and valves.
- The wheel design cannot be handed between left and right designs.
12.4.5 No wheel material is permitted in the following exclusion zones :
- A concentric cylinder of diameter 305mm and length 115mm positioned with its inner face lying in the same plane as the inboard face of the front wheel.
- A concentric cylinder of diameter 305mm and length 25mm positioned with its outer face lying in the same plane as the outboard face of the front wheel.
- A concentric cylinder of diameter 305mm and length 100mm positioned with its inner face lying in the same plane as the inboard face of the rear wheel.
- A concentric cylinder of diameter 305mm and length 30mm positioned with its outer face lying in the same plane as the outboard face of the rear wheel.
2013 F1 Technical Regulations 45 / 78 25 September 2012
© 2012 Fédération Internationale de l’Automobile
12.4.6 When viewed perpendicular to the plane formed by the outer face of the wheel and between the diameters of 120mm and 270mm the wheel may have an area of no greater than 24,000mm2.

[yener]

I believe that the rims are only dimensionally regulated:

Front 305-355mm; rear 365-380mm

However, you do have a very good point in that lighter rims could potentially be used to lighten the car during stints.
But there is a caveat.

Why would a team run heavier mass on all four corners of the car when it could be lighter? The more central and lower the mass is, the better.
So if a team is using heavier rims during qualy, and lighter rims during stints.... it's to paper over cracks in their initial calculations of their concept or possible issues with fuel consumption/mass(they may run heavier alloys at the end to be legal).

So my guess is, they would run the lightest possible alloy at all times.

The car including the rims would be as light as possible. So the minimum weight of 640kg including the "heavy" rims. But they could use a extra set of rims whih are way lighter then the ones which they parc at parc ferme.

Lets say rims weight normaly 3kg a rim. Then they should put 5kg rims and adjust the rest of the car to get a min weight of 640. After the first stop they can change to the 3kg rims and then run a couple of kg lower.

It would be illegal, but since the fia cant prove rain in monsoon (RB FLEX) this should be possible.

[megz]

A great idea, but given the rule below

12.3 Wheel material :
Wheels must be made from AZ70 or AZ80 magnesium alloys.

It can't hold water, the material is more or less the same for all teams - the only way to make them heavier is to make them unnecessarily thicker in all areas which could influence brake cooling etc.

Cheers to Strad for posting said rule.

[KeiKo403]

Can't scrutineers call a car into the weigh bridge at anytime during a qualy in-lap?
I'm sure drivers have had penalties and reprimand's before now for ignoring stewards calling them onto the scales when entering the pit lane.

[FoxHound]

Can't scrutineers call a car into the weigh bridge at anytime during a qualy in-lap?
I'm sure drivers have had penalties and reprimand's before now for ignoring stewards calling them onto the scales when entering the pit lane.

Of course.
But they cannot call a car into the weigh station whilst in-race.

[Lurk]

Anyway tyres are mounted on rims by Pirelli if I'm not mistaken. So someone who is not part of the team will have the light rims on his hands.

Plus the gain will only be during a third of the race. Better to have light rims with "heavy" car all the time than heavy rims with light car 66% percent of the race or more, plus qualifing.

[FoxHound]

@Yener

As strad kindly posted before, they are limited to the type of magnesium they can use. The difference would have to be measured in grams, and the effort required along with the dubious rule breaking implications would not make this an avenue worth exploring.

Nice idea though.

[FoxHound]

Anyway tyres are mounted on rims by Pirelli if I'm not mistaken. So someone who is not part of the team will have the light rims on his hands.

Plus the gain will only be during a third of the race. Better to have light rims with "heavy" car all the time than heavy rims with light car 66% percent of the race or more, plus qualifing.

Brings another question to light...Will Pirelli inform the FIA if the rim where to be underweight? I wonder what power they have in this area.

[Lurk]

I think that even if Pirelli don't directly talk to the FIA about that, Formula one is a small world. One of the Pirelli guys will speak to someone (journalist, colleague, friend...) and quickly everybody will hear about the trick, Charlie included.

[strad]

you make a rim out of specified material to a specified size and thickness...It's gonna weigh the same every time.

[marcush.]

wasn´t it rims needed to be homologated and you have to stick to the one design released before seasons start?

[yener]

Anyway tyres are mounted on rims by Pirelli if I'm not mistaken. So someone who is not part of the team will have the light rims on his hands.

Plus the gain will only be during a third of the race. Better to have light rims with "heavy" car all the time than heavy rims with light car 66% percent of the race or more, plus qualifing.

Brings another question to light...Will Pirelli inform the FIA if the rim where to be underweight? I wonder what power they have in this area.

Foxhound I understand that they have to be made of magnesium.

But they party can make the tyres of heavy metal. It's not the fia is going to split the rim to see if they use anything other then magn.

They have to fit the Tyres self on the lighter rim, so even Pirelli would not notice it.