What about this idea? Alcons on 17" snow wheels?
 

What about this idea, I now run the 370mm Alcon brakes so 19" or special 18" with extra space is the smallest you can go in rim size, but I want to run 16" or maybe 17" ice "spike" tires to go extremely fast on an ice track.

So why not buy a set of used A4 B7 front brakes and run them for winter use? Get some extra grip with high performance brake pads?

And for a bonus not getting winter dirt and salt on you expensive Alcon dics!

Nice idea, keep us up to date.

Bad idea.
 

Brakes are all about front/rear balance and changing out your fronts to A4 rotors would destroy the balance. The A4 brakes are inadequate for the power of the RS4. Lots of other issues to consider.

proportioning valve...

May in fact be able to code the ABS/ESP module for use with smaller brakes...
 

which controls proportioning. Haven't done any research on this, but it may be possible, it may not.

When going to ceramics the module must be coded to work with those units.

Cheers,

Brakes can be coded, and will run low gripp pads for the rear

wow! like the look of your Porsche, nice!

You should likely be fine if the ABS/ESP module can be coded for the smaller brakes...
 

as that will control your proportioning. I moved from Porsche based brakes during the summer on my turbo converted 90q20v down to twin piston calipers so I could go back to 15" wheels for winter for several years. Just have to be aware of the changes in grip and fade resistance, however fade resistance with gummy snow tires when on snow/ice really wasn't a huge factor;)

Cheers,

Thanx the info.

In theory you are correct. However, you have not taken into account all factors.
 

What he is proposing involves using snow tires. Braking power is used against traction. Regardless of road conditions, most brakes out there will have the power to kick in ABS on the RS4 if it has snows on it. The fact is, snow tires cannot generate that much traction. Therefore, the limiting factor is not braking power, but traction. As long as the front/rear balance is sufficient, there would be no problem with this.