ltooz_a6_a8_q7

Hello all,
I finally took the A8 to the Sierra, CA last week. The car was great on the icy snow road until I had to brake hard and I can hear the ABS pumping and pulsating my brake pedal. The car doesn't stop, it's slipping and sliding, I was glad that I kept a good distance from the front car.
Is this normal or my ABS brake system is bad? It doesn't do it when it's raining or dry roads. The brake system is very smooth and efficient besides these ICY snow road.
Inputs are greatly appreciated.

Jkay

Please say which tires you have on, and how worn-out they are. Even Blizzak WS-50s only use the *special* micro-tube formula for the first 60% of the useable tread, then you're riding on normal tire formula.

JimR

4 x 0 = 0; quattro and ABS do not enable defying the laws of physics

ohbw

Hear! Hear!

ltooz_a6_a8_q7

The tires are Dunlop Sport 4040 or something like that with about 20k miles on it (50% tread left?). The road is like this
<img src="http://pictureposter.audiworld.com/61809/icy_road.jpg">

My concern is the ABS pulsating noise and the force pulsing back to the brake pedal. I have not experienced this before.

<img src="http://pictureposter.audiworld.com/61809/truckee.jpg">


Thanks,

JimR

Stand on the brakes, get used to what ABS sounds and feels like, so you don't lift off from being startled in a panic situation. You will feel pulsations in the brake pedal as the ABS controller modulates, and will hear a "grinding" noise. This is normal.

JimR

<a href="http://www.tirerack.com/a.jsp?a=AR4&url=%2Ftires%2Ftires.jsp%3FtireMake%3D Dunlop%26tireModel%3DSP%2B40%2BA%252FS">If this is the tire you have</a>, it doesn't appear too great in the snow.

If you're not in a place where you do wintertime snows, you might consider upgrading to <a href="http://www.tirerack.com/a.jsp?a=AR4&url=%2Ftires%2Ftires.jsp%3FtireMake%3D Michelin%26tireModel%3DPilot%2BSport%2BA%252FS">th ese</a>, the next time you need tires. I love mine, and they did well in snow/ice for me at Christmas.

Jkay

That's a big part of your problem. The noise and grinding and pulsing is proper ABS feedback.

Jkay

For winter dry-weather performance, but snow/ice traction too, I suggest the Blizzak LM25 .. they have a 235/45-17 size which should be perfectly fine .. anyone have a definitive answer on that? (Randy?)

For ***** to the wall all-out winter ice/snow grippage, go with Blizzak WS-50 .. the WORD in unstudded hardcore A8 winter tires. They come in the proper 225/55-17 size.

JimR

If he does a lot, he should get a set of snow tires/wheels.