I thought I'd share my recent experience to see if other drivers have suffered similar incidents.
I was driving a Vauxhall Omega saloon, 3.0L automatic, rear wheel drive. The road was wet but thankfully empty.
I was accelerating up to speed on the motorway with only a slight left hand curve to the road. The rear of the car started to slide at 50 mph'ish and then the car started weaving violently from side to side. I presume it was my reaction to the initial skid that set it off but once started I had no idea what to do but hang on, brake and hope.
Was there anything I could have done once the slide had started? What caused the snaking?
I'm now scared stiff of driving anything with more than 95 bhp!!!
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Dave,
Rear wheel drive may give the ultimate balance for the sporting driver in the dry, or in the wet with a wide test track at your disposal, but this is just what they can do on a wet greasy curve to catch you out.
Others can tell you exactly what you should have done step by step but all I'll say is you need the minimum steering/throttle change/input to correct the problem and probably not the brakes.
I've had some hairy moments in the past with powerful RWDs but far far less with FWD.
MM
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Dave,
Once the back had started to slide the best thing to have done was to come off the gas and gently steer in the direction of the slide in order to stabalise the car. Braking is the last thing to do as that is likely to make the situation worse. The car started to snake as the rear tyres regained their grip and the energy had to go somewhere so it forced them back in the other direction. Called a tank slapper when it happens on a bike and often results in the rider being pitched off the machine.
If the back starts to snake it is possible to regain control by accelerating, but it requires expert throttle sensitivity and needs lots of off road practise to get right.
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I stuck 245/45/17" tyres on the back and rarely have this problem now.
The original 205/15" Kumho tyres on the back of my Omega stopped me from going round wet roundabouts at anything more than 5mph! Moving upto 15" Continentals helped a fair bit as well. Khumos leave a lot to be desired in my opinion.
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I'll agree with Tom there. Very gentle lifting of the throttle and corrective steering to prevent "fish-tailing" down the road.
Now you've done it once though, the next time won't be half as bad.
Paul Ripley always used to say the worst time to learn skid control was in an emergency.
I think if you ask your local police, they sometimes organise skid-pan days. A good idea for the owners of powerful RWD cars.
Rob MKIV Supra (not used in this weather)
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Rob MKIV Supra (not used in this weather)
Family friend had one of these and once couldn't get up the slope that led to his road. He reckoned any slippery conditions and it was almost uncontrollable.
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>>What caused the snaking?<<
Initially your rear tyres lost grip because they were not just having to cope with the cornering forces, like the fronts, but were also dealing with the acceleration forces as the car is RWD. As you back off instinctively, weight transfers from the back to the front, reducing the rear grip even further, making the problem worse. Think of a motorbike doing a wheelie then a stoppie for an extreme example of weight transfer!
In a RWD car the answer is to back off very gently. If you are not going much too fast, there may be a point where the grip comes back in and you keep control. If that point isn't there then you are stuffed anyway.
If you do lose control, you do have time to think and make decisions. Standing on the brakes is OK when you are at 60mph and 20 yards from hitting a brick wall, but it's often better to steer than brake - with all wheels locked up your steering does nothing at all. If you think about your situation - which is typical - with locked brakes you can only go further out into the corner (in this case into the traffic). But if you leave the brakes and keep the steering, you can at least aim away from trouble.
PB.
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davef,
I got into exactly the same trouble a few years with a borrowed Carlton 3.0GSI automatic when I kicked down to overtake whilst still exiting a bend at rather a high speed. The car was the owner's pride and joy but thankfully he wasn't in it!
Having driven in the days when snow-covered roads were not salt treated to any extent, I instinctively *eased* off the accelerator pedal whilst turning gently into the direction of slide. The common mistake in these situations is to overcorrect the steering and this leads to uncontrollable snaking.
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By the way, though I agree generally with PB, I think the problem with backing off the accelerator too quickly is not really to do with weight transfer. The problem is that, with a closed throttle, the engine compression is *braking* the rear wheels at the worst possible time. Ideally there should be no braking of any kind whilst you are correcting a slide.
The accelerator should be eased just enough to provide nil braking or accelerating of the wheels. If this cannot be achieved in the heat of the moment I think it would be better to declutch (on a manual car!). Declutching is also a good idea when sliding on ice.
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I'd concur with that exactly, Dizzy.
The rear wheels should neither be trying to accelerate nor slow the vehicle.
The front wheels should be pointing in the direction you are trying to go.
Only hit the anchors if things get out of hand i.e. if full lock on the steering isn't enough to point the front wheels in the desired direction..
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You are absolutely right about the engine braking effect, which reduces the available grip directly and because of weight transfer. Ideally you need a neutral throttle position that is neither driving or braking the rear wheels - backing off gently gives you a chance to find this position. The real message is to do everything very gently and progressively and think about regaining control rather than simply stopping. There's certainly no substitute for experiencing this on a skid pan or a racetrack.
PB.
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Just be thankful you weren't driving one of these, then!
abcnews.go.com/wire/Business/ap20030107_113.html
It's all relative...
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PB, Tom & Dizzy have covered it nicely - I wouldn't under estimate the influence of the automatic kickdown.
The sudden dropping of a cog as you corner is much more violent than a manual change and this often provokes a slide in wet conditions.
Anyone caught out like this in a heavyish saloon would be doing really well to hang on to it - it's hard enough when you're expecting it!
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Dead right, Steve! Some automatics now prevent gear-changing during distinct cornering (can't recall which ones) and that seems a very good idea, even if it does involve yet more electronics.
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Believe it or not, I've been suffering the same effect on damp, gritted or icy roads in a 7.5t lorry! I can only assume it's a combination of excessive torque, weight transfer whilst cornering, and rear tyres designed for longevity and puncture resistance rather than grip. The technique for me seems to be to accelerate in straight lines only, and to hold the throttle steady (ie neither accelerating nor decelerating) when going round a corner.
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a 7.5 ton taxi, Dave? ;)
The Astra has a 'cold weather' setting, which keeps the gearchange-speed right down when engaged. Car starts off in third, would you believe... disengages at about 50mph.
Not that I'd ever have to use it on local roads, but ...
(The stupid thing is that they bring in a car with this feature, but omit rear foglights!)
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Whilst there has been some excellent written replies to the correct procedures to counter a fish tail skid, there is no replacement for actually experiencing skid control correction on a skid pan, under professional instruction. In fact I feel that all drivers should be made to attend such courses. If you run a search on Google - "Skid Pan Training Courses", you will get details of various centres around the country. I have recently sent my son on such a course, and he said the experience was invaluable, and hopefully will stand him in good stead for life!!
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Ian - are you a piston ring salesman? ;-)
there is no replacement for actually experiencing skid control correction on a skid pan, under professional instruction.
Dude - Surely you mean: "Wet carpark after a few beers".
--
These are my own opinions, and not necessarily those of all Toads.
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Toad : don't know about wet car park, but whenever we get a covering of snow I find the nearest big empty space... It's always a good idea to know what it's going to feel like, and what you have to do to get it to let go.
Mother in Law picked up her first car with ABS on Saturday : we went straight to an empty car park so she knew what it felt/sounded like when it worked.
Pleased that conventional wisdom now says 'hit the clutch and don't touch the other pedals' in a skid ; I nearly failed my driving test on that one when conventional wisdom used to say "feet off the pedals"
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Ian - my 7.5t taxi can be seen at:
groups.msn.com/honestjohn/davestaxiphotos.msnw?action=ShowPhoto&PhotoI
D=61
taken on the way back from taking two 8ft long commercial freezers to a supermarket in Perth!
Posted this in the middle of a thread about diesel spills by mistake - it's getting late...
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I had the same problem in my boy racer days - MkII Escort driving around the city of London. Ended up pointing the wrong way down a one way street after a race to get away from some traffic lights, 30-odd taxis and buses breathing down my neck hooting at me...
...me, egg on face, learned a valuable lesson that day...
Splodgeface
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Another personal experience:
Driving in to work yesterday morning on the A7 into Edinburgh - went round a sweeping left hander, and went round further than expected/intended!
The back end started to slide, and I assume I must have over corrected, ended up fish tailing, and shortly thereafter came to a halt facing the wrong way, having gotten far too intimate with a stone wall - result one truly trashed Mondeo TD.
Interestingly worst damage to driver's side front and back corners, with the driver's side rear wheel (and suspension) totally wrecked... The hatchback imploded quite nicely all over the parcel shelf, and I'm fairly sure the chassis was bent, as some of the the doors, though not obviosly damaged, didn't want to open easily.
Was doing about 35-40 in a 40 zone, with 3 day old tyres on the front. I assume I must have gotten unlucky in the first instance and hit a patch of ice, then didn't recover it very well. All happened quite fast after the initial "oh, it's sliding a bit..."
Abaddon
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This is an instance where more grip on the front can actually cause the problem - its the same prinple as lift off-over steer. Lift off - weight transfers to the front, loading the fronts and giving them more grip - rear becomes light, hence losing grip and comes round. Oversteer in a front drive car is really difficult to control as it comes on REALLY quickly, as you found out. Lots of people with 205 GTis will testify to this!
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Thanks for all the advice. It all helps me come to terms with the incident. Although we survived it's not looking so good for the car which now rests in the hands of the insurance company.
The final twist to the incident in question was that after "fish tailing", the car veered violently towards the crash barrier and "crunch/ spin".
Bottom line seems to be:
Seek expert tuition on a suitable test pan.
Avoid kick down acceleration when cornering, especially when wet.
No braking or accelerating whilst in slide but gently steer into the slide until grip returns. This seems the bit to experience "safely" as you would be steering away from the desired direction.
"fish tailing" results from overcorrecting the slide and is bad news, as it seems the only way out is to speed up again. I guess at this point it's keep the wheel straight and hope the road doesn't run out.
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A couple of weeks ago I posted about my similar experience at low speed on a damp roundabout. The rear tyres on the car at the time were Kumhos fitted by the previous owner - in the wrong size! Now that correct size Bridgestones are fitted, the car has been much more stable, even on the 6 miles of untreated ice before the A-road I've had to cover each day this week. Still, it's easier in this weather in a FWD car.
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Nail on the head andymc, FWD or 4WD for me too, not been interested in any RWD since i lived on a very steep hill, the two RWD cars i had failed to get me onto my drive, moving to fwd solved the problem, leave RWD to drivers who like the rear meeting the front.
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jud, I agree that FWD can be better on steep and slippery slopes -- but don't forget the disadvantages at other times:
# Weight is lifted off the driving wheels on acceleration
# Hooking up a trailer also takes vital weight off the driving wheels
# Torque-steer can be a problem
# The turning circle is often compromised
# The ideal of a 50/50 weight distribution is difficult to achieve
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"The ideal of a 50/50 weight distribution is difficult to achieve"
And probably not even desirable, as it would reduce traction even more! FWD cars do accelerate well in reverse, though.. :-)
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I put an auto Carlton into some railings once: coming out of a roundabout, dark, wet, maybe even a little icy, floored it, got kick down, which pushed the back out and spun all over the place. I think I froze, and was actually accelerating as I hit the railings.
Just as well I was 18 and illicitly in my dad's car while he was on a trip to the USA then....
That, at least, taught me the value of skid control- though best learned at slow speed in the snow in a carpark. Not sure whether you need the few beers, Toad!
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