superswiss

Today's modern cars have EBD (Electronic brakeforce distribution) instead of fixed bias valves. These systems send the appropriate brake pressure to each wheel based on speed, traction, load etc. In some systems, EBD distributes more braking pressure at the rear brakes during initial brake application before the effects of weight transfer become apparent, or in other words as stated above to avoid nose dive under braking. The rear brakes are sized so that on average both front and rear wear about the same. The fronts normally still do more work, because the rears can only do so much before locking up. But brake wear depends a lot on driving style and if the car is driven in a way that ends up favoring the rear more than expected, then you have increased wear in the rear. Regular light early braking for example will do that instead of late braking. With my RS5, the fronts still wear faster, but I tend to downshift and use engine braking to moderately slow down the car instead of riding the brakes and generally brake late in line with a more dynamic/sporty driving style.

scoopman

I guess I'll just have to start stabbing the brakes later before the turns next time :-)

superswiss

Or divebomb into corners

Slides

Remember that Camry behind you doesn't have brakes as good as your car!

heisnuts

You might want to check them on the parts pricing. Looking at some of the online dealers, it looks like MSRP for the parts should be $401 (or $481 if 2 sensors are needed... It looks like there might be only one sensor per axle). I would also check out the dealers website as they will usually have a "service specials" link under service where you will find coupons for service and sometimes specifically brake work. I see Audi Marin has a coupon for service that will give you 15% off if you spend over $400. If they don't have it on their website, you can always ask if they would be willing to extend a discount for you on the work or match one of the other dealers in the area.

scoopman

Thanks for the responses -- definitely going to attempt to negotiate today on pricing. I needed my car and didn't want to drive around with worn brakes, and also don't have the time during my day, so decided not to take the car back and do lots of shopping around, independent garage etc. Audi Palo Alto actually has a 15% off brake coupon on their site, and I expect something off from this job to match this if these guys want to hope for my business to replace the fronts when those go relatively soon.

Questions:
-- For the future, do the rotors really always need replacing at the same time? 20k still seems awful short an amount of distance for the rotors. This seems more like a procedure for the dealer to make more money on every brake pad job.
-- For the fronts, if I were to go with an after-market harder material pad which theoretically would last longer, are there any concerns about two different pad materials from front to rear?

J. Patterson

20k miles is really soon to replace rotors. If not worn thinner than minimum thickness stamped on the rotor they can be turned and reused. I just did this on a friends TTS and will be doing it on my S5 before long. ( my original brakes are at 39k miles.)

For a street driven car, I would keep the pads alike as far as compound is concerned. Different compounds have different friction coefficients and could affect braking balance. A very good OEM replacement pad ( that will save $) is the Centric Posi Quiet Semi Metallic. I have used them on several Audis and a Porsche. Every bit as good as OEM in my experience. Not suitable for track use though. ( but neither is OEM)

scoopman

I'm looking at replacement pads, and there's not much aftermarket selection for the S5 SB. The two I'm looking at are the Power Stop Z16s (link) and the Chrome Brakes Ceramix (link).

The Power Stop is ceramic but is mostly advertised as low-dust but not higher performance. It also seems to be reasonably priced. (Power Stop's Z23 performance compound isn't available for the S5). Not sure if the Z16 will offer me better pad life than I got with the OEMs.

The Ceramix are a combo of semi-metalic and ceramic claiming to offer the benefits of ceramic without the drawbacks of ceramics when cold. But they're much more expensive.

Anyone have experience with either of these or other leads on pads that might be less-soft than the OEM ones?

scoopman

Quick update: I went with these pads (thanks for the suggestion).... I saw too many concerns / feedback expressed about ceramics to think it's not really what I want here. Very little choice in non-OEM brake pads, which is surprising based on the evidence that plenty of folks are seeing early wear like me and the B9 S4 appears to have same brake pad sizes.

J. Patterson

Very good. I hope and expect you will be pleased. I have a set incoming for my 2015 too. This discussion prompted me to pull a front and rear wheel and inspect closely. Inner pads a bit thinner than outer both front and rear. If I go ahead and swap them now I can reuse the sensor for front. My original pads at 39000 miles! ( manual trans car. Less brake wear due to engine braking.)