LittleDonny

There are a lot of "fictitious" forces - and they are called fictitious because they do not exist in the real world. For example, electromotive force is a "fictitious" force - it isn't a force at all, it is a fancy name for potential difference (voltage). Centrifugal force cannot be represented on a free body diagram, therefore for all intents and purposes, it does not exist.

Bottom line is that cross-drilling helps wet braking performance, but how much is up in the air. Water stuck between the pad and rotor will reduce friction. The water has to be pushed out of the contact area because it cannot be compressed (well it can, but it takes more pressure than a caliper can provide and even then only by about 4%). The water seeks the area of lower pressure contantly, eventually making its way out of the contact area (we're talking fractions of a second). Now, having holes in the contact area would theoretically allow faster dispersion of the water between the pad and rotor because the water simply doesn't have as far to go and there are more places for it to go. This may explain why the initial bite is less effective in the rain, and gets better with drilled rotors.

technical

Now show me a free body diagram of water managing to find its way onto the rotor while driving on the freeway in the rain.

trackbird

iTrader: (4)

If somebody wants to break out the rotors and test gear (and a hose) we can prove or disprove this thing real quick. (I bet disprove is the word of the day). I'll supply a vehicle and a few drivers.

mitchntx

iTrader: (14)

It's not worth the fuel to disprove.

There are myths out there that have porpogated through time that will continue to propogate regardless of any effort to disprove them.

LittleDonny

I don't see much water getting on a rotor at speed, but I don't see none getting on one either. And I also don't see crossdrilled rotors helping any noticeable amount in the rain, but it does help on a minuscule level. Certainly not enough to warrant the downsides of crossdrilled rotors.

VIP1

OK, maybe I should have said that the "effect" exists and it is percieved as a "force". I aced College Physics, but that was 6 years ago. Granted I forgot much of it and tend to generalize. Are you in Physics now or is this your area of expertise?

I'll second that.

Louis

iTrader: (7)

brakes get too hot to even have water on them. We actually ran water nozzles much like an intercooler sprayer on turbo cars for the brakes on hard race courses. The water is vaporized long before it touches rotor.

Feel the rotor after a drive around town, Youll be suprised how warm they are.

technical

And when you're done, stick your tongue on the headers and see if they're warm also...

Louis

iTrader: (7)

maybe we need slotted headers to aid in water repellant

VIP1

trackbird

iTrader: (4)

Don't forget "cross drilled" on those headers.....

VIP1

mmm

Slotted and cross drilled headers..... that would sound interesting. Maybe a bit better than the rusted out exhaust on my mother's 1990 Chevy Lumina.