This is the first winter that I have owned my 1990 C2 Cab, and already the UK weather is doing its best to upset things.

In heavy rain, I am experiencing a disturbing tendency to aquaplane where 'rivers' of water run across the road. At any speed over 60mph the 964 loses traction and feels as though it is about to go sideways. Fortunately, so far it has regained grip quickly enough for me to stay pointed in the right direction.

My tyres are all only about 1,000 miles old (Continental Contisports, 205 front, 255 rear). I have a strut brace which was fitted by the last owner, and I wonder whether the springs may have been changed also at some point.

My questions are:

- Has anyone else experienced aquaplaning problems similar to this?
- Is the strut brace/ possible change of springs likely to have much effect?
- Any other suggestions on how to eliminate the problem?

Any help very much appreciated.

Cheers,

Jeremy.

 

ContiSports are meant to be very good in the wet...

 

Hi Jeremy,
I also have Conti Sports and am very happy with them but on returning from Bramham Park this year in torrential rain I had a major aquaplane passing a massive truck shunting out water (a very scary experience to say the least!!)

Firstly are your Conti's "N" rated?? you said they are almost new so the groove depth won't be a problem.
Secondly, maybe someone could answer this one, does Geometry set-up play any part in this??

Cheers
Gary '91 C2 (tip)

 

Hello,I have Conti Contact tires also. I have
experienced severe hydoplaneing this summer
when I got caught in a south Texas rain storm.
My tires have very few miles. I attributed
the hydroplaneing to the depth of the water
(12-18 inches),the speed that I was traveling,
the width of the tires,and the flat under-
carriage of the Porsche. (I still have my
engine pan attached.)
I also have an American road rocket that has
extra wide tires that also hydoplanes but not
to the degree that the Porsche. My wife's
lux-cruiser has regular width tires and exhibit
very little hydroplaneing in high water at high
speeds. <img src="graemlins/yltype.gif" border="0" alt="[typing]" />

 

Aquaplanning danger usually starts above 50 mph. If you have wide tires you will aquaplan sooner than with narrow tires. Newer tires stick better, but can still aquaplan. It pays to slow down when it rains heavily. Trucks often leave rails in the road which can fill up with water and cause aquaplanning. At night, especially it is difficult to see how much water is on the road, and you can be suddenly in a dangerous situation. Life is short - don't speed when it is raining heavily... <img src="graemlins/wave.gif" border="0" alt="[byebye]" />

 

911's have a 40-60% weight distribution front to rear. The front would be first to plane obviously and would be most susceptible because of its relative lightness. I agree...slow down.

 

Dear Jeremy,
Winter and Contisports do not match. Your tyres are summer tyres. Once the road surface is below 7 degrees C leave the C2 at home or you may well end up leaving it somewhere else.
Ciao,
Adrian
911C4

 

I live in Cheshire UK, probably as wet as you can get, have driven 993 + P0, 993 + contisport, 996 + contisport and 964RS + bridgestone SO2 in such conditions . For most of UK no real distinction between summer and winter so Adrians advice bit hard to go by.....all the above car / tyre combos were prone to aquaplaning, so I think its normal, you just have to live with it and be careful. Skinny tyres especially on ice & snow are much better than fat tyres...but you are not going to fit those are you

 

Oh how the brain retains trivial info (that comes in useful sometimes). I remembered something about tire pressure vs. hydroplaning as it related to aircraft. A quick search of the NET came up with this :

The formula that is used to
compute hydroplaning speed is: Minimum total hydroplaning
speed (knots) equals 9 times the square root of tire inflation pressure (psi) or:
V = 9 ÆP

So for that 36 PSI front tire, it's 36 ^1/2 = 6*9= 54 MPH.

Of course, the "variables" come into play, tire condition, road condition, etc. So your speed may vary!

 

So, Lou - - - would the formula apply to that Goodyear or Goodrich rain tire that touts it can hold a gallon of water (or some such ridiculous amount) in the large groove running down the cener of the tire?

Chuck
93 C2

 

Thanks Guys for the info - all useful stuff.

But does the stiffness of the suspension and the associated mods make the situation worse in your experience?

Thanks,

Jeremy.

 

Chuck (scupper)

I don't know about Goodyear Aquatreads, but formula applies to a F-14 touching down with the tires inflated to 225 PSIG.

BTW - wheels look great.