AQUAPLANNING IN BELGIUM

AQUAPLANNING IN BELGIUM

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The Specials

Original Poster:

88 posts

132 months

Tuesday 21st October 2014
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Driving back from Mons Belgium in the company Focus Diesel at 120 kph and in difficult driving conditions and the warning signs about aquaplaning on the overhead. However, the Focus was fine through any standing water at 120kph and so were the white vans. Then we start to slow down and there is a new Porsche 911 rear end into the barrier and badly damaged. He may have been over 120kph, but not much as there are so many cameras around and the density of the traffic does not allow speeding. The standing water was about 100m before the spin and in subsequent standing water the Focus passed no trouble. I can only assume it was not a 4WD or that the tyres were crap. I was really surprised to see the car had spun as I would have thought, like the Focus and vans, it would literally sail through this type of standing water. PS: I don't post much on here, but enjoy reading and thought your Porsche aficionardos would be interested.

PTT

664 posts

120 months

Tuesday 21st October 2014
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Standing water and wide tyres are a bad combination.

996TT02

3,308 posts

139 months

Tuesday 21st October 2014
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PTT said:
Standing water and wide tyres are a bad combination.
Aye, wide tyres. Narrow tyres will cut through because the distance water has to travel to clear is shorter.

robgt3

2,585 posts

161 months

Tuesday 21st October 2014
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God Bless insurance!! Hope our friend is okay.

Rockster

1,508 posts

159 months

Tuesday 21st October 2014
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Even with new tires on either of my Porsches I can sometimes detect the early signs of hydroplaning if I let my car's speed get too high. And I'm not talking about autobahn too high of speed either I'm talking about staying at under 75mph down to even 65mph.

Thus I always when the roads are wet try to keep my car's speed down.

I've never had it happen to me but I have watched a couple of cars leave the road due to hydroplaning and it happens very quick. Since the tires are not making contact with the road braking or steering have no real effect and the driver (and any passengers) is (are) just along for the mostly likely very bumpy ride.

My Porsches are the worst for this tendency to hydroplane of any cars I have owned, except possibly a Dodge D200 pickup truck with fat tires and no weight over the rear axle. That thing would hydroplane on a humid day.

robgt3

2,585 posts

161 months

Tuesday 21st October 2014
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Oh! Boy looking forward to all this aquaplaning stuff!! My fettled Aston V8S was pumping about 470 brake. Going on a jaunt with Petrol Head Nirvana up and over the Alps wearing nothing but Potenzas in serious rain I can honestly say that they never ever let go. So in my soon to be GT3 what can I expect?

PTT

664 posts

120 months

Tuesday 21st October 2014
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Just be gentle with the loud pedal in the rain and you will be save.

sunbeam alpine

6,936 posts

187 months

Tuesday 21st October 2014
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It has been exceptionally wet in Belgium today (and the road surfaces aren't always brilliant). I had a couple of wobbles, and I was driving a Ducato van.

Edited by sunbeam alpine on Tuesday 21st October 20:09

SkinnyP

1,411 posts

148 months

Tuesday 21st October 2014
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Too many factors at play to say its the car or tyre width to be honest.

Yes very wide tyres may not clear standing water as well as narrower tyres but these things arent clear cut.

speedyellowrs

468 posts

206 months

Tuesday 21st October 2014
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IIRC, aquaplanning can occur at about 8 x the square root of the tyre pressure, give or take 5 mph, depending on tread depth. So anything more than 48mph on a well treaded tyre inflated to 36psi, or above 43mph on a lightly treaded tyre, could make for an interesting moment in standing water.

Happy to be corrected by someone smarter than me!

hondansx

4,562 posts

224 months

Tuesday 21st October 2014
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I have 315s on the back of my C4S and, despite the 4WD, it felt all over the place on the M20 when the rain was coming down a couple of weeks ago. It was torrential, but white van men were going over 80mph and i was having to back off at that speeds as i was getting silly having to make minor corrections with the steering!

Funnily enough, on the same stretch about 2 years ago i saw a 911 in the barriers on a rainy day. Now it makes sense!

Taking the GT3 on Cups to Snett on Friday... bring on the hurricane!

WindyMiller67

426 posts

139 months

Tuesday 21st October 2014
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This thread has just brought back a bad memory! (Although the ending was happy.) 27 years ago, when I was 20, I had an Alfasud Sprint with relatively fat tyres for that era . My sister was 18 and had just passed her test and had just bought her first car a 0.9l Fiesta! I don't recall where we were going, but for some reason we had to go in two cars and it was absolutely lashing it down with rain and there was standing water everywhere. She was ahead of me as we passed through our high street and I started to feel my car aquaplaning / torque steering. At 25-30MPH it was fun. I noticed my sister was pulling away... Then I remembered, as we leave our village, the 30MPH zone becomes national speed limit (it's 40 today - boo) and after a small hill, a horrible right-hand bend with an adverse camber. My sister was away - I just could not catch up with her to flash her and warn her about the right-hand bend. The rain was so hard, and the road a river, I just about maintained my speed but certainly couldn't get any traction down to increase speed. I can remember with such dread the helpless feeling I had as I was certain I would brow the hill before the bend and see her red Fiesta in the ditch. She wasn't there! Phew - she was now 1/4 mile further up the road! Her skinny tyres just sliced through all the water like she was driving on rails. When I eventually caught up with her at our destination, having nearly ruined my pants and fallen off every bend along the way, she calmly asked, "What happened to you?".
Thanks for jogging my memory! Happy days...

thegoose

8,075 posts

209 months

Wednesday 22nd October 2014
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speedyellowrs said:
IIRC, aquaplanning can occur at about 8 x the square root of the tyre pressure, give or take 5 mph, depending on tread depth. So anything more than 48mph on a well treaded tyre inflated to 36psi, or above 43mph on a lightly treaded tyre, could make for an interesting moment in standing water.

Happy to be corrected by someone smarter than me!
I'm confused as to why that calculation isfor pressure and speed? I'm sure many of the white vans mentioned are running pressures not disimilar to the sports cars, but with vastly different abilities to move water and resist aquaplaning.

Wozy68

5,387 posts

169 months

Wednesday 22nd October 2014
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robgt3 said:
Oh! Boy looking forward to all this aquaplaning stuff!! My fettled Aston V8S was pumping about 470 brake. Going on a jaunt with Petrol Head Nirvana up and over the Alps wearing nothing but Potenzas in serious rain I can honestly say that they never ever let go. So in my soon to be GT3 what can I expect?
You really want to know?
http://rennlist.com/forums/991-gt3/801096-porsche-...

The guy has gone back to (me thinks) Aston.

Seriously, I'm just over the county line from you. If you need someone to drive it back from the OPC, I'm more than willing.
Infact I'll scrub those tyres in for you a wee bit as well, so just leave her with me for a month or so ...... well until after Christmas maybe. smile

speedyellowrs

468 posts

206 months

Wednesday 22nd October 2014
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thegoose said:
I'm confused as to why that calculation isfor pressure and speed? I'm sure many of the white vans mentioned are running pressures not disimilar to the sports cars, but with vastly different abilities to move water and resist aquaplaning.
Hi Marcus,
I believe the size and shape of the contact patch is also a factor. The long thin contact patch of a van tyre will be less likely to aquaplane than the short wide one associated with a sportier tyre.
Again, happy to be corrected by someone with better engineering knowledge than me!
SYRS

Slickhillsy

1,772 posts

142 months

Wednesday 22nd October 2014
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robgt3 said:
Oh! Boy looking forward to all this aquaplaning stuff!! My fettled Aston V8S was pumping about 470 brake. Going on a jaunt with Petrol Head Nirvana up and over the Alps wearing nothing but Potenzas in serious rain I can honestly say that they never ever let go. So in my soon to be GT3 what can I expect?
You'd definitely have been ok in the Aston as you have a great lumping motor pushing the tyres through the surface water. Hence (partly) the reason the Focus was ok in the OP (helped also by thinner tyres). Any mid / rear engine car (especially those with wide tyres will be at risk).

I once wrote off a perfectly good 348TS in Switzerland after getting caught out in a freak rain storm in Switzerland... Nothing quite like aquaplaning at about 70 odd, spinning and then gliding down the motorway sideways. I came to rest on the hard shoulder having taken out a few saplings en route. Most amusing of all was that the Swiss authorities sent me a bill for thousands to 'repair' the grass and trees!!!
Fricken Swiss - gotta love um...



GoatRider

72 posts

140 months

Wednesday 22nd October 2014
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Be careful indeed. 2011 in the 997 GT3 on the way back from Le Mans and I arrived back in Blighty to lots of rain and pools of standing water. Never having driven the GT3 in that much rain I had a couple of real ring tightening moments as the back slithered away. I couldn't keep up with my mates and in the end I thought I was going to crash so I radioed the guys to wish them well and pulled into the inside lane at about 50mph, and even then the rear end felt squirmy. When I compare that to a rock solid Chrysler Voyager at 115mph in a proper Euro storm in Germany a few years back and I'm just glad my GT3 experience didn't involve Armco. The cause is mainly to do with wide tyres, light weight body and the rubber cut. Interestingly my super light and over powered Ginetta G33 did the 'run' a couple of years before and covered the entire return trip in torrential rain without a single moment. It's an issue well worthy of the occasional reminder to new 911 owners.

Lost soul

8,712 posts

181 months

Wednesday 22nd October 2014
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SkinnyP said:
Too many factors at play to say its the car or tyre width to be honest.

Yes very wide tyres may not clear standing water as well as narrower tyres but these things arent clear cut.
It is well known that wider tyres will be more affected than narrow

thegoose

8,075 posts

209 months

Wednesday 22nd October 2014
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I'm surprised no-one's linked to the UK 80 mile 991 GT3 that was written off due to aquaplaning. It was before the engine issues came to light which was ironic because the accident caused the engine to land about 50yards away from the car!

PTT

664 posts

120 months

Wednesday 22nd October 2014
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Aquaplanning killed this Dutch Porsche driver last February in Belgium.
So, be carefull in the rain and adjust your speed.

Edited by PTT on Wednesday 22 October 17:36


Edited by PTT on Wednesday 22 October 17:37