[stracha]

So I picked up my M4 Comp xDrive last week, and decided to complete my break-in period as soon as possible. After 300km, I went out on the highway, it was raining, and I was fully aware that with race track tires you basically have no grip on wet roads. With that in mind, I set my speed to 80 kmh and turned Driving assistant with maximum distance set between car in front of me (the car in front of me looked sooo far away). I thought, well if I am going that slow (80kmh!?) and car in front of me looks so far away, it is going to be fine. Suddenly, three cars in front of me, car stopped, and all three cars started packing one on another. Driving assistant starts slowing down, then I hit the full brake and watched my car glide towards the pile of cars in front of me. I steered, and managed to avoid the car in front of me and to stop 2 inches from road fence and the car that crashed in front of me.

Takeaway - race track tires have basically no grip on wet road, and Driving assistant is not calibrated to account for this! On wet roads the car behaves like a car with a summer tires on a snowy road. Be very careful!!!

[Dethsupp0rt]

Honestly not sure what this has to do with Driving Assistance.

You're on (basically) slicks in the wet, which is the only real takeaway from this whole scenario. Don't do this.

[Tyga11]

Must be on the P Zero's - absolutely astounded how they can put these tires on any car with the way they perform in the wet.

[stracha]

Originally Posted by Dethsupp0rt

Honestly not sure what this has to do with Driving Assistance.

You're on (basically) slicks in the wet, which is the only real takeaway from this whole scenario. Don't do this.

Well, it is not something you can choose if it starts raining. If they already have all sorts of warnings, rain sensors etc, I think the system should at least warn driver that Driving assistant is not functional with slicks.

[spridge]

Originally Posted by Tyga11

Must be on the P Zero's - absolutely astounded how they can put these tires on any car with the way they perform in the wet.

I must have received the good set of pirellis. They work just fine in the rain for me.

[Tyga11]

Originally Posted by spridge

I must have received the good set of pirellis. They work just fine in the rain for me.

Not for me - I had to pull over during a heavy storm a month ago. Was doing 40 mph and was hydroplaning across the freeway.

[Bimmr7]

Originally Posted by stracha

Well, it is not something you can choose if it starts raining. If they already have all sorts of warnings, rain sensors etc, I think the system should at least warn driver that Driving assistant is not functional with slicks.

Are you serious right now? You clearly stated you knew that wet and slicks were not ideal. If the tire is what meets the road why would you rely on an electronic system.

[M3AWD]

What do you mean when you say racing tires?

[JTO24]

Or he has the optional cup2s that some countries offer as part of a track package.

[AndroidRobot]

Originally Posted by stracha

Well, it is not something you can choose if it starts raining. If they already have all sorts of warnings, rain sensors etc, I think the system should at least warn driver that Driving assistant is not functional with slicks.

driving assistant doesn't fully stop you that fast which is why it requires you to pay attention. AEB is for emergency situations not careless driving

[PLF69]

Read the manual before operating machine.

Pretty sure there is a mention somewhere to NOT do what you said you did..

I also have driving assistant in my car and I caught it many times stopping right into a bend, I took time to learn its limits and now it's been a wonderful partner for all sorts of drives.

[forza1976]

User error.

[Transfer]

So the other cars crashed but you avoided collision despite incorrect understanding of the safety tech on the vehicle? Sounds like tires were at least ok. Sometimes we all learn things the hard way.

[chicagofan00]

Originally Posted by Tyga11

Not for me - I had to pull over during a heavy storm a month ago. Was doing 40 mph and was hydroplaning across the freeway.

Too be fair though, the freeways flood here in AZ pretty damn easily if we get anything equivalent to a down pour or more. A couple of the storms we've had over the last month brought some torrential rain.

[vampire81]

what tires are on the car? michelin cup2?

[stracha]

The tires are Michelin cup2, my mistake for not reading the manual, taking the test, getting a race driver certificate or whatever.

I had a 2017 S class (with regular tires though) with assisted driving which prevented you from having a collision, always, from 0-200kmh, whether it was turned on or off, it was working perfectly. I expected BMW's to do the same with the 80kmh with the highest distance setting.

Obviously, inexperienced people (like myself) buy this car too. The point of this post was to warn people like me that these tires are really really really bad on wet roads. So bad, that car should limit speed to 100kmh when it is raining, or something like that....

[vampire81]

i regretted putting cup2's on my C7Z. not only un-drivable on wet roads, but tires need to warm a bit in winter months also.
for me, PS4 or equivalent is the way to go.

why would the Driving Assistance system not work in your situation is weird. the good thing you avoided a crash.

lesson learned: don't depend on the computer and be alert at all times.

[Gfit]

Glad you are okay. Thanks for sharing. Perhaps you will save a wreck or even a life if someone else didn't know.

[vj123]

I am glad that you were safe. So there are two aspects in your incident.

Driver assistance system:
I develop these systems for living. Radar and other sensing modules takes real time input from other modules (brakes) and it should be compensated lack of traction in this particular scenario. Not sure if this was a real time test case when they developed the system. I do not add any driver assistance packages on any of my personal vehicles as the technology is still maturing.

Tires:
Looks like other cars crashed infront of you and ts highly unlikely that all those vehicles had summer / slick tires as well. There might be an external cause why that patch of road had less traction. Maybe black ice or oil spill? Any manufacturer does tons of testing and they wouldnt qualify a tire for a particular vehicle if its unsafe. Safety is the first criteria in any tire development and its placed above cost or profit. BMW wouldnt chose a tire on this vehicle if it was really unsafe.

A simple google search shows that these tires are in several performance vehicles. People do drive their high performance vehicles in rain and those vehicles have more hp than a M3.



Several external factors are involved in this incident and not sure if i will just blame the manufacturer as a whole.

[Bimmer TiM3]

I feel like this thread should be titled "Do not trust that being able to purchase a nice car means you have brains".

[forza1976]

Originally Posted by stracha

The tires are Michelin cup2, my mistake for not reading the manual, taking the test, getting a race driver certificate or whatever.

I had a 2017 S class (with regular tires though) with assisted driving which prevented you from having a collision, always, from 0-200kmh, whether it was turned on or off, it was working perfectly. I expected BMW's to do the same with the 80kmh with the highest distance setting.

Obviously, inexperienced people (like myself) buy this car too. The point of this post was to warn people like me that these tires are really really really bad on wet roads. So bad, that car should limit speed to 100kmh when it is raining, or something like that....

So you put cup 2's on the car after delivery?
This was not an option from the factory if I'm not mistake.

[BMWRacer523]

complete user error. you drove with cup2 in the rain and you expected an electronic nanny to save you? where's my facepalm emoji?