Aquaplaning in a Z4

S

Sceptre

Member
 Cambridgshire
I was having a spirited drive from London to home last night.

Very heavy rain and strong winds.

I hooked up with a Jag XF (too dark to see model inscription but boy it roared from traffic lights.

We had about a 30 mile play - it was that, not a race - good manners from both but spirited.

I know most of the water spots on the A1 out of London but the depth of water was so much more than ever before.

My tires are about 4mm of tread at the moment (run flats) but I have to say that the ESP on aquaplaning corners was magnificent. I hate to say it gave me confidence but I must have aquaplaned about 6 times on that journey. Credit to the Z4 handling and to the inferior ability of the XF.

What thoughts have you got on aquaplaning in the Z4?

Sceptre
 
Thats interesting.. a quick google on some crude stats:

XF vs Z4
Tyre width: Comparable (245/40 R18 for the Jag)
Weight: XF:2330kg vs Z4:1470kg
Due to the weight difference I would expect the Jag to survive longer.

In an aquaplaning scenario ESP/DSC isn't going to help you much until you regain contact with the road.

I dont understand why handling would effect aquaplaning likelyhood?
 
The other major variable I thought of as I posted that would be that the XF is front wheel drive.. Z4 rear..
That maybe the reason :)

Happened to me once.. scared the life out of me!! :rofl:
 
and you have no way to knowing his tread depth versus yours. New tires will outperform worn out tires in the rain every time, regardless of brand.
 
Street said:
The other major variable I thought of as I posted that would be that the XF is front wheel drive.. Z4 rear..
That maybe the reason :)

Happened to me once.. scared the life out of me!! :rofl:
Click to expand...

Jag XF - rear wheel drive. Only the X Type was front and only then in basic 2 litre and 2.2 diesel models.
 
Guys - I wasn't using this as a Zed beats Jag post- Driver skills will always be a bigger decider than the car (except on a drag strip).


The point was that I was amazed and started to abuse the confidence given be my car when aquaplanning. When I twisted on a slide (as I entered 'lake' whilst on a bend) the car corrected itself without a worry. I'm sure the Jag has the same ESP capability but I am sure the driver got scared of the event rather than realising what the tech did for him.

Three cheers for the Zed's ability on aquaplaning. This was not a race with a Jag, merely a reference to another spirited driver.

Regards

Sceptre
 
DSC doing it's job :)

That is where you really want it, when you are caught out and it makes a potential loss of control a less potential loss of control!

The Z4 will be my first car with TCS or ESP, but I look forward to having it there as a backup for the rare times you are caught out by standing water or fuel spillages on the road etc.

Dave
 
I remain bemused on rereading this post that after aquaplaning on well worn tyres, (which if you were truly doing and not just skitting an odd wheel about a bit, equates to a complete loss of any ability to brake, steer, etc.) you would repeat that another 5 times on a public road.

The various electronic aids on the Bimmer are good but cannot as BMW themselves remind overcome the basic laws of physics.
 
If you really aquaplane then all wheels loose contact with the ground and you 'float' on a layer of water. You can't steer and can't brake effectively. It is very dangerous and no DSC/TC will help you until the wheels regain contact with the road! I've seen some pretty nasty crashes posted on various sites where aquaplaning was supposedly the cause. Be careful out there!
 
A few times I've exerience what I thought was aquaplaning. The car felt like it moved sideways a little without grip. It wasn't even for half a second but it felt like the car was on ice before I felt grip again.

Is that a brief aquaplaning experience?
 
Yeah, that's aquaplaning. It's not good.

Street said:
XF vs Z4
Tyre width: Comparable (245/40 R18 for the Jag)
Weight: XF:2330kg vs Z4:1470kg
Click to expand...
Not sure if those weights are acurate, the XF looks like a gross weight. Kerb weights are more like XF:1800kg, Z4:1300kg. But your point still stands, the XF would be less likely to aquaplane with comparable tyre contact areas.
 
bras0782 said:
A few times I've exerience what I thought was aquaplaning. The car felt like it moved sideways a little without grip. It wasn't even for half a second but it felt like the car was on ice before I felt grip again.

Is that a brief aquaplaning experience?
Click to expand...

Yes - as the tyres cease in ability to be able to remove water from the road to remain in contact caused by a combination of speed, depth of water, width of tyre and tread depth /pattern and weight, the car rises up and skims(planes) on the water. From that point and until something changes (end of the water, speeds drops, etc._ there is zero grip, traction, steering. Often the car will rotate as it was likely off balanced as it entered the water.

I've done it numerous times on skid pans and you can have all the electronics in the world and they are useless until the tyres regain bite on the road. From then on it's just luck if the combination of electronics, driver and amount of road are enough to regain control in time before ........

People often mistake simply hitting a puddle on one side and pulling the car with a bit with aquaplaning
 
Hey CJ10jeeper,

I didn't go back to the same puddle over and over again.

I continued on my journey on a very very wet night. Would you have pulled over and waited for the rain to stop and water flow away? I might have been traveling fast but feel with the width of our tires and weight of car, aquaplaning would have occurred at anything over 50mph.

Would 4mm tread be called well worn? I'm looking forward to shodding Falkens on the car in March/April but feel that the conditions were bad enough to cause a car with new tires to aquaplane too.

Most wet spots I could anticipate due to knowledge of the road (I've driven the A1 from London to home about 4000 times - no kidding). The worst spot on the A1 for sitting water has to be XXXX where I have met 12 inches of water before.

As for training, I used to spend hours and hours on ice covered car parks and snow covered quarries in both front, rear and four wheeled drive cars. With Stig Blomqvist (http://en.wikipedia.org/wiki/Stig_Blomqvist) and Ari Vatanan (http://en.wikipedia.org/wiki/Ari_Vatanen) as my hero drivers I tend to like the sideways approach in life.

Sceptre
 
How fast do you call fast in such conditions :o

Doubt I'd have been travelling much more than 40mph given your description of the conditions...

Electronic aids only go so far, and can get things wrong :(
 
I'm really not looking to argue and am sure you're a superb and skilled driver. Do as you will because you're a long way from any road I'm likely to be travelling onin the opposite direction, but if in your judgement 50 would have caused aquaplaning, then that would be too fast. I'm all for amazing antics with cars, and seem to have spent half my life upside down or sideways down in a Jeep, or getting out of some stupid situation I drove into, but not in uncontrollable conditions on a public road. Save it for the circuit, or at least quiet roads out of the way of others. Do it enough times and you'll run out of road sooner or later.

4mm - well for a high performance car driven as you like to then I'd say they are getting to the end of their life useful life, compared to the legal min of 1.6 and original of 8mm.
 
Ive aquaplaned mine a couple of times, thankfully for only a metre or so and never at any serious speed, but it scares the hell out of me.. Particularly as i read quite a few posts on here last winter of people writing off zeds (often Ms) by doing this. Ive always thought that a relatively small low weight car like mine with huge tyres is incredibly susceptible to this, so i ease off massively when i think i might inadvertently go swimming..
 
Sceptre said:
I was having a spirited drive from London to home last night.

Very heavy rain and strong winds.


Sceptre
Click to expand...

I think the answer is in the first 2 sentences...........not the ideal situation.
 
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