larryV

After going through many sets of stock pads and a set of Pagid RS14 Black compound race pads, not to mention a set of rotors, the following are my observations and a few thoughts regarding brake pad wear.

The image below is that of a brembo GT8 brake system as found on an A8 W12, which is basically the same system on the RS4 except ours has cross-drilled rotors. I have used it here to illustrate the brake wear patterns I've found on my car. The red/dark red numbers correspond to each individual brake pad on the brake system, with the bright red numbers 1 and 2 corresponding to the outer brake pads and the dark red the inner pads. (2 pistons per brake pad, 4 pads total each caliper assembly)

The brake pad on position #3 exhibits the most wear compared to the others and in some instances (after a hard flogging at the track), that particular brake pad has shown the most cracking near the edges, and it just plain looks toasted at times. The brake pad on position #2 is second, and the ones on #1 and #4 show the least amount of wear relative to the others. While 1 and 4 seem to have the same amount of wear, 2 is actually closer to them than it is to the amount wear 3 has. Bottom line is that brake pad #3 takes one hell of a beating during heavy use. This is consistent with the brake pad wear patterns on both driver's and passenger's side.

My thoughts: it makes sense that #3 will show the most amount of wear over the same given period of hard use since it is on the inside and above where there would seem to be the most heat and least airflow. While there is actually a cooling duct that directs intake air from the bumper into each front fender (just in front and inside of each front wheel), it is not exactly focused cooling and if anything it just seems to cool the front part of the rotor where there are cutaways of the rotor splash guard, and not the caliper itself.

Why should you give a ****?: While brake pad rotation seems like a ridiculous concept, if you frequent track events and don't mind swapping your brakes yourself between street and track compounds on a somewhat regular basis, it would at least be wise to keep track of which particular brake pad you are replacing when doing swaps. For example, when I swapped my track pads out yesterday to put my street pads back on, I made sure to install the thickest brake pad on position #3 and the rest accordingly. This is especially important when putting the race pads back on so that when the brake pads run thin, I can not only ensure I can get the most out of the set but also reduce the risk of running brake pad #3 down to the backing plate and consequently damaging the expensive rotor (which I've already done on this car). Since replacing the front brake pads is very easy to do on this car (possibly the easiest I've ever found on a any car), I say why not rotate them when possible?

The wear patterns seem to be the same for both the stock pads and the Pagid race pads when driven hard but during normal use (away from the track), the wear differential between individual brake pads are less exaggerated. This means that those who don't track their cars or don't brake aggressively on a regular basis should just ignore this post and let your brake pad wear sensor tell you when your stock pads need replacing.

<img src="http://homepage.mac.com/lvelano/.Pictures/random/brakesd.jpg">

Bob W.

...perhaps switching to the smooth-face rotor from the A8 W12 would reduce pad wear. IIRC, cross-drilled rotors decrease 'gassing' (excessive temperatures) at the pad/rotor interface at the expense of eating through the pads quicker.

Der Kimbo

The A8 W12 does not use the Brembo 8 Piston, 16.2" Rotor steup system Larry posted above. It is on the Bentley Continental Family of Cars and the RoW Phaeton W12.

larryV

isn't it on the euro W12? either way, image was purely for illustration purposes

Der Kimbo

No worries...Just clearing up or Bob's reply.