Crazy Idea

The reduction of receprocating mass (rotating weight) is a major aspect of proformance, so why don't they intagrate the wheel and brake rotor? Create a wheel with an inner ventalated lip with a calaper built onto the suspention arm. It would not only give more surface area to the pads but it would lighten the whole assembly because the intagrated rotor becomes a structrual unit of the wheel. Yes I know that you would have to insolate the heat from the inner wheel so it does not expand the air in the tire but I don't think that is too hard an engineering challenge. Just a crazy idea give me your feedback.

so that if you need to change brake disks you HAVE to change the whole wheel?
what if you want to change brakes from let's say a 4 pot to a six pot system? change the whole wishbone?
does that also mean that the manufacturer has to produce a bespoke wishbone for every car out there?
same goes for the brakes.
What if you want to have a carbon ceramic brake system, does that mean you HAVE to have a carbon ceramic wheel as well?
also, if the brake caliper is going to be fixed to the wishbine, then there would have to be a ball joint of some sort to allow for the movement needed in the suspension. If you're going to have this anyway, it doesn't make sense to integrate the calipers to the wishbones as you will still have a hub and caliper.

too many flaws in terms of pure product design.

And, as you said weight is the enemy here, especialy rotating mass.

By building the disc into the wheel rim your moving mass away from the center of rotation which means its needs more force to make it spin, and it takes more force to make it stop spinning.
And because the disc would have to so much large, it would also be a lot heavier.
And, finnaly, I can imagine heat disapation would be a real problem.

Its a really nice idea that actualy works well on push bikes, where the wheel rim is used as a the braking surface, and Iv seen motor bikes where a thin, drilled, light weight disc has been bolted inside the wheel rim, but the extra weight and complexity in a car design makes it impracticle on anything with more than 2 wheels.

so that if you need to change brake disks you HAVE to change the whole wheel?
what if you want to change brakes from let's say a 4 pot to a six pot system? change the whole wishbone?
does that also mean that the manufacturer has to produce a bespoke wishbone for every car out there?
same goes for the brakes.
What if you want to have a carbon ceramic brake system, does that mean you HAVE to have a carbon ceramic wheel as well?
also, if the brake caliper is going to be fixed to the wishbine, then there would have to be a ball joint of some sort to allow for the movement needed in the suspension. If you're going to have this anyway, it doesn't make sense to integrate the calipers to the wishbones as you will still have a hub and caliper.

too many flaws in terms of pure product design.

OK here are a few ideas
build it with a six or eight piston system standard so you would never have to upgrade it.
Yea you would have to make a wishbone for every car you produce, but this is not exactly supposed to be a "partsbin car" anyway
No carbon brake rotors could be intagrated with aluminum wheels.
You would not have to fassion the caliper to the wishbone but it would help keep it in proper prsition during suspension bound.
Like I said just a crazy idea prob too impractical for production just serching for an ideal setup.

I took my brakes off, I just have Doctor Phil ride with me and he talks to the car and works with it, and gets it to stop itself under its own will power.

Roflol!!!!!!!!!!!

Good one LOL

I think the keys here are heat and articulation. It would be very difficult to isolate heat. As it is, your wheels take a lot of heat from the rotors since they're bolted to them. If you use the actual wheel surface as a brake friction surface, not only would it require the use of an unsuitable material for the wheels, but the wheels will get screaming hot; probably hot enough to melt the bead of the tires.

You would have to build the wheels out of cast iron or forged steel which is not only a very unsuitable material for wheels, but its insanely heavy. You would (as someone pointed out) be forced to change wheels when the rotors wore out.

Basically, the setup that is in existence right now does what you're talking about. The rotor is basically part of the wheel since its bolted to it. Simply moving the rotor to the wheel itself wont save you any weight, and it will move the weight you have outward on the radius making polar moment of inertia worse.

Trains usually use the wheel as the brake disc. But their wheels are made in a suitable material.

If you integrate wheels and brake discs there are several problems that you run into. The heat from the dics will transfer directly into the wheel, but at the same time if would be difficult to get a good cooling flow through the discs.

Since aluminum and magnesium, common alloys used in wheels are unsuitable to be used as a friction surfaces you need to bolt a friction material onto the wheel. Differences in heat expansion and temperatures of the parts will tend to cause thermal stress followed by cracks.

Also, when the discs are worn out, you need to replace the whole wheel or the friction material applied to it. Also, if you need to replace the wheels, due to wheel damage or when you change between winter/summer tires, the disc also have to be replaced.

another problem you'd encounter in this is the pressure of the air in they tyre changing. brakes often pass 1200 degrees C and if this was attached to the wheel itself then you'd heat the air in the tyre too. this would cause the pressure to rise and the tyre would expand. so under hard braking your tyre would expand, your contact patch would reduce in size and your braking distance would increase dramatically.