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Driving along a sodden M4 last night with lots of standing water I rembered HJ's advice not to use cruise control in such conditions, (because when the front wheels slow, if they aquaplane slightly, my rear wheel drive car tries to speed up). Thanks!
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What car is this?
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I don't believe that for one second!!!!
My rear wheel drive car has ESP so will detect if ANY wheel is rotating at a different speed to the others and cut the power/brake accordingly. It certainly won't speed up.
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I'm with mscott, I've changed my behaviour as a result of HJ's advice which tied-in with a bad experience I had a few weeks ago.
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A forum like this can be a very good way to share useful information and learn how to deal with tricky situations.
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Surely it's common sense not to use cruise control in *any* adverse weather conditions?
Or maybe people need the 'don't dry your wet dog in the microwave' type of instructions these days.
I often wonder if people grapple with setting their wipers on the correct speed, wondering if the rain qualifies as 'heavy' to allow them to use speed 2. I suppose auto wipers have solved that dilema for some drivers.
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The CC on my Vectra-C automatically switches off in an event such as aquaplaning.
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On the motorway yesterday the rain and spray reduced visability down to not much more than 100 metres. However, visability wasn't impaired enough for the headlamps on the 56 reg Disco 3 to switch on, and if the car doesn't want them on, why should the driver bother. So he didn't. Idiot.
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Please will someone post a link to HJ's advice on this? Some people think it is terrific - one person thinks it is nonsense - perhaps we could read it and make up our own minds? I have tried a Forum Search and got no result
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"On the motorway yesterday the rain and spray reduced visability down to not much more than 100 metres. However, visability wasn't impaired enough for the headlamps on the 56 reg Disco 3 to switch on, and if the car doesn't want them on, why should the driver bother. So he didn't. Idiot."
The trouble is that auto lights are based on brightness rather than visibility. Yes the guy in the Disco should have thought of it but I must confess that with Auto headlights it's easy to forget.
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My 206 has auto lights, if the auto wipers are also activated & your doing more then 50mph the headlights lights will come on as well.
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Please will someone post a link to HJ's advice on this?
It wasn't on hear, or if it was, I cant find it. It was mentioned in The Telegraph.
www.telegraph.co.uk/motoring/main.jhtml?xml=/motor...l
Skid solo
Driving down the M20 in very wet conditions recently, I hit a large puddle at 70mph. My BMW 325i aquaplaned, then skidded violently. Only luck and the absence of other road users avoided a potentially serious accident. My car has 29,500 miles on the clock and is still on its original tyres, although they are due to be changed soon. I have driven in similar conditions before without mishap. Could this incident be down to misfortune or might there be other contributing factors of which I am unaware?
A.R., via e-mail
Your tyres are at the limit of their ability to disperse water because they are worn out. Don't economise by making tyres last in winter - change them tomorrow. Also, don't use cruise control on a rear-wheel-drive car in very wet conditions. The speed sensors are on the front wheels and if the rear wheels start to spin they might start to do so uncontrollably in an effort to maintain the car's pre-set speed.
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I've just read the piece in the Telegraph and it states that the speed sensors are only on the front wheels and therefore the car will accelerate as it thinks it is going slower than it actually is.
ESP monitors all 4 wheels individually, each wheel has its own speed sensor. Acceleration in these circumstances would be cut by the ESP as per my original comment.
Your thoughts most welcome.
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ESP monitors all 4 wheels individually,
Surely would depend on the car.
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The problem is common in America, where the combination of rubbish RWD cars, cruise control, heavy rain and drivers of low ability make such aquaplaning under power more common, the drag of the deep water, reduced the cars speed, so the car accelerates to maintain it which then spins the wheels and can lead to loss of control.
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>> ESP monitors all 4 wheels individually, Surely would depend on the car.
No it doesn't depend on what car at all. ESP monitors all 4 wheels, traction control monitors only the driven wheels.
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No it doesn't depend on what car at all.
Chill out man. You may disagree with HJ's advice, I don't really see any need to appear so angry about it.
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No it doesn't depend on what car at all.
It does if the car doesn't have ESP. I think you'll find the speed sensors HJ is refering to is for the CC, and not the ESP / TC.
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water I rembered HJ's advice not to use cruise control in such conditions, (because when the front wheels slow, if they aquaplane slightly, my rear wheel drive car tries to speed up). Thanks!
Why would your wheels slow when they aquaplane ?
Why would non-drive wheels slowing cause the car to slow ?
Why wouldn't various stabilty control stuff react ?
and perhaps the thread title is just a tiny little bit ott ??
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Why would your wheels slow when they aquaplane ? Why would non-drive wheels slowing cause the car to slow ? Why wouldn't various stabilty control stuff react ? and perhaps the thread title is just a tiny little bit ott ??
1, aquaplaning doesn't just mean skimming across the top.........it means not in contcat with the road. Most of the tyre could be trying to pile through water, which will slow you down
2,.... see 1,........anything trying to go through water slows
3, might take a moment to do so.......at speed that could be the difference between going beyond what the ESP can do for you
4, didn't find it that way myself.....took it to mean that someone was glad to have been told something that they previously didn't know about and now make sure they adhere to for their own safety
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Unless those brakes are sticking, I struggle to imagine an aquaplaning undriven wheel slowing down in terms of rotation significantly - the drag from the water will tend to keep the wheel spinning, not stop it.
Number_Cruncher
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The extra energy it takes to push the wheels through deep standing water slows the whole car down NC. Anyone who has ever driven through a deep puddle has felt the car decelerating, and if the puddle is on one side only, trying to turn as well. That is the moment when the driver has to know what is happening, do the right thing and not do any of the wrong ones.
I imagine HJ's advice applies to older, cruder cruise control setups without any of the trick save-you-from-yourself traction and braking controls found these days...
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>>The extra energy it takes to push the wheels through deep standing water slows the whole car down NC.
Indeed Lud, I quite agree, but as I understand it, HJ was suggesting that if an undriven wheel slows down during aquaplaning, via its speed sensor, the cruise control would act to speed up the car. My point was that under aquaplaning conditions, the rotational speed of an undriven wheel would probably not be dramatically different, as the water drag would tend to keep the wheel rotating at a speed commensurate with the forward speed of the car, not to stop it turning.
I think HJ's advice, suggesting that people turn off their cruise control in very wet weather is sound, largely for the same reasons that you give in your post, but I don't think much of HJ's supporting logic.
Number_Cruncher
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NC
I think you're right about the wheel-speed staying virtually constant, as there's less overall drag once the wheel rises onto the surface of the water. The vehicle may indeed speed up momentarily.
HJ's advice applies only to the comparatively rare [over here] vehicles that have ABS-type speed sensors on a front wheel, but no actual ABS/ESP.
As stated; ESP would detect [and correct] a slew or skid virtually before the driver had even noticed it.
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Maybe some of us mean driving through deep standing water, rather than aquaplaning over the top of it? I know I did in my post as I was using the term looseley.
Driving through deep water at high speed on one side will pull the car that way due to drag, if it is on both sides the whole car will slow down. That is when the CC will try and boost your speed.
Look at how standing water is used to brake log flumes, test rail cars, rocket tests etc...
www.ejectionsite.com/stapp/19.jpg
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I think HJ is in danger of starting an 'Urban Myth' - I can't think of any car that his suggestion would apply to.
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all these driver aid gizmo,s take the art out of driving,what will they think of next , proximity sensers to aid parking more than likley.. tut!
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I think the best way to save a life is to slow down in the wet weather.
Drove home on m5/m6 sunday in horrendous weather and was pressing on as much as I dared. Had to use wipers at full speed in stages and would not (not could not) drive any faster. Got good tyres fitted all round and have done more then the average driver in severs condition (rallying)
Absoloutely astounded at the speed of others going past me and how close they were to each other (and to me at stages). There is no way they could see more than me, or react much better than me, or control the car, or spot problems etc etc. To anybody that went past me; you are an absoloute idiot, and 1 of the reasons why so many speed cameras are in place; even though in places the nsl was too high! But dont let that slow you down!
Bring back driving standards and ability, not aids that wont always save you !
Way more important than whether wheels will slow down down or not in a puddle !
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