Slipping on ice

[Sweed]

My 07 XC70 seems like is sliding a lot more than usual on mildly icy roads. The ABS kicks in extremely soon but the car still slides almost through stop signs. I am running 4 studded snow/ice tires as well. When taking off is also seems to not hook up quite as well as it did. In comparing it to cars I drive at work and my other vehicle, it's just not great. I was thinking wheel speed sensors, but no codes. Any ideas?

[oragex]

When the ABS kicks in, do you press with force on brakes ? On some cars we can actually get shorter braking distances on ice by pressing the brakes just enough 'before' the ABS kicks in.

How are the brakes ? May also lift and spin rear wheels see if the handbrake shoes may have delaminate and locking the wheels - just an idea

Done recently a brake fluid purge or brake job ? Thinking maybe air got inside the brake lines - or worse, inside the ABS unit

Also make sure not to drive in W mode - for the acceleration thing

[vtl]

How old are your tires? How many studs left?

[Rattnalle]

How old are your tires? How many studs left?

This is my question as well.

Personally I find it very noticeable when the tyres loose grip and the cars tech tries to help out. So it's quite easy to tell the two apart. This goes both for braking and accelerating.

Regarding ABS it's not supposed to optimise brake distance vs a skilled and prepared driver primarily but to keep some sort of steering ability plus reducing reliance on the driver braking the right way in a panic situation.

[vtl]

I always get a much shorter braking distance by pumping the brakes, like our fathers did. Much shorter than ABS can do (if it can).

[Rattnalle]

I always get a much shorter braking distance by pumping the brakes, like our fathers did. Much shorter than ABS can do (if it can).

I've tried that numerous times but the result is always that it's quite useless when it's actually really slippery. I've tried on several cars as well. A firm press but just not enough to lose grip is often the best, abs next best. In my experience.

If it's really slippery it's not an issue though since it's not possible to gain or keep much speed anyway

[- Pete -]

I’d be checking to see if the rear wheels are were getting power. If not, you’ll probably be looking at doing a DEM pump, collar sleeve, hopefully not a bevel gear though. Any are a possibility if the rears aren’t getting power.

Also, you can do the rudimentary DEM test by pushing and holding the “read” button on the turn stalk & simultaneously pressing the rear fog light button twice. Then you can push the read button to go through all the modules scanned. DEM should report “ready” if it’s functioning right.

[Sweed]

Ok, ill try to answer all these.
1. Only missing a ouple studs on the right rear tire. The siping and tread depth is close to like new.
2. If it's even remotely icy, the ABS kicks in with even the slightest amount of applied brake force, but still continues to slide way too far IMO.
3. Front brakes are new. Rear are still in great shape. As for brake fluid, I have not changed it, however, I know the feel of air in the lines
and this does not feel like that. I did have a booster vacuum leak which has been remedied.
4. Rear wheels are engaging. I have tested this often by doing some serious drifting on snow and ice for fun! It hooks up decent when being overly aggressive. Unfortunately the law wont allow me to drive like this.

Just as a comparison, our lightweight Ford Focus we had with all season crap tires, stopped way quicker than this thing with studded winters. My truck is the same and it weighs 9000 lbs and has crappy worn tires.

[vtl]

ABS kicks in when the vehicle starts to slide. ABS is not the cause of bad ice braking, but an indication of bad traction of your tires.

I've been using a lot of crappy plastic eco tires in the beginning that have had great MPG, but ugly traction. Now all my tires have lowest UTQG possible (wear out quickly), MPG is down from 24 to 19 on highway, but they are grippy. Current Volvo tires are Vredestein Quatrac 5 (XC70) and Pro (XC60).

[Sweed]

Ordinarily id believe that, but these tires were on our focus originally and worked awesome on that car which was only front wheel drive. Maybe the volvo is just not the greatest on ice.