Magellan55

It was raining today, and I think my front wheels locked up while attempting to stop at a traffic jam on the highway this morning. Pretty freaky to hit the brakes and hear screeching up front and the car sliding while doing 70. Luckily I had some space in front of me and didn't hit anyone. No indication that ABS was activated on the dashboard, and no pulses through the brake pedal. I've got over 30 years of experience driving both ABS and non-ABS cars in bad weather, and this definitely felt and sounded like the latter. This has happened to me before on snow / ice, and each time I took my HS into the dealer and they said everything is fine. My tires are decent Michelin MXM4's with plenty of tread left.

Anyone else have this happen to them? Does the ABS light come on when it activates for you? I get a traction control light when that activates when accelerating on slippery roads, but no ABS light. My ABS light does come on for a second or two when I start the car, so the light works.

Am I just going crazy, or is my dealer incompetent?

TheAirman

The light won't come on.

That's the thing about some ABS systems. You think the tires are locked up like the old days because you hear your tire screeching, but they aren't. They are right there on the edge, though.

The system is applying just enough pressure to stop the wheel from turning and giving you the maximum braking force, that's why you heard it squeal, ...BUT.... it also is releasing the pressure enough so you still have steering control.

You might of thought they were locked up, but if you had to whip the wheel and steer, it would have done it, unlike the pre-ABS days where you would have just skidded out of control.

The HS has a very hi-tech, advanced electric brake system. It'll react differently in different conditions. In my case, when I come down this steep hill with a stop at the end, right before the stop is this frost heave in the road. When I hit that bump and hit the brakes hard, the tire must leave the road instantaneously, because I definitely hear mine pulsate just like the "other" systems.

Try it this winter on a snowy road. And by the way, did you hit the brakes hard enough to feel your seat belt auto retract and just about strangle you to the seat back? If not, you haven't hit the brakes hard enough yet. When that happens, it's a real eye opener!

Magellan55

Thanks Dave. No, I didn't hit the brakes very hard at all - the car started sliding pretty quickly, and pushing the brakes harder did nothing at all. next time this happens, I'll try turning the wheel, though I was pretty focused on the back bumper of the truck in front of me this time :-) It really surprised me - the car behaved like it was on a sheet of ice but it was 70 degrees and just raining.

I'm concerned about the tires too of course, ABS or not they should not have lost traction that fast in rain. Michelin has a new compound they used on this generation of MXM4; it's possible it hardens faster than the old compound. The tires are only 2 years old and have about half the tread left, with no uneven wear.

About once a year, we get an icy rain that leaves roads pretty slick with black ice. I'm planning to have my kid out there (up on a hill) video me as I drive down our road with the brakes locked up - it will be the final proof whether my ABS is working or not :-)

TheAirman

We get a little heavier winter stuff here in W. PA.

When the roads are covered, it's fun to try to make the car go out of control on a snowy road and test out the stability control. You get to feel each individual wheel brake as the car bring itself back into line.

What I do is on a curvy road, on an uphill part ( so in case you lose it, you scrub off speed real quick) is I way over correct on the corner, and force the car to spin out, The wheel that needs to will stop, and the car will right itself.

You'd be surprised just how hard it is to get a modern car with stability control out of shape. You'd have to be going to fast for the conditions to wreck.

ABS is a different matter. You won't stop any faster, which is a mistaken idea a lot of dead people had, but it will allow you to steer while braking the hardest without losing control.

Magellan55

I'm going to have to disagree with you a bit on that last statement :-) ABS also allows shorter stops, as the coefficient of static friction is higher than of kinetic friction on most materials. For tires on dry roads (not sure about wet ones), kinetic friction is only about 80% of static friction. The optimum point to maintain is just at the edge of slippage, also known as "threshold braking". Now, it won't be a ton shorter, but it is shorter. The big exception is on something loose like sand or gravel, where it's better to lock them up to plow up a pile of it in front of the tire.