Well, in the past I have had a few minor wiggles in the rain with my XK8, but nothing to get excited about. I think somebody back a year or two had a thread explaining the reason these cars wiggle when hydroplaning in the rain. Camber I think? This morning it was wiggles as usual in the rain and I took my time and slowed down. Sadly, as I passed Kitchener I spun out with all four wheels "floating" on a river of water flowing across the 401. I think it only took 2 seconds and I was into the concrete barrier. I'm OK, and so is my friend, but the XK8 is another story. She is now a parts car.
I think anyone with this model should drive very gingerly in a heavy rain or pull over to wait for the storm to pass. (Or figure out how to stop the wiggles)
Alfred

 

I recall a thread where alignment issues were discussed WRT this model being a bit over-eager to hydroplane.

However, I'm sure tires must also play in to no small extent. So, what tires, specifically, are you on?

Cheers
DD

 

Hydroplaning is 75% tires, 20% driving speed and 5% suspension. Any car will hydroplane with the wrong tires, worn tread or higher speed into standing water. ANY CAR.

Glad you're OK...sorry to hear about the damage.




.

 

Damm another 03 bites the dust...sorry to hear about your troubles and happy all are OK. Big wide tires do act like a flat bottom boat!

 

Tires were Michelin Pilots on all four. Rear tires 4 years old with 80% tread and front one year old with 90% tread. I understand tires... my father worked at Uniroyal for 35 years and he ingrained on his sons a desire for the best rubber when driving. I also understand why a car hydroplanes, but what bothers me more and more since yesterday's event is the wiggling on small puddles and the final one that turned into a full spin while other cars only seconds in front and behind me hit the water without any consequence. As we waited for 30 minutes for the tow truck it began to rain hard again and I could see at least one hundred of cars negotiating the "river" at speed and continue on their journey.
On a side note, none of the front airbags deployed despite hitting the concrete at 80 km/hr. We spun around and hit the barrier a second time on the passenger side and the side air bags did not go off either. Thanks to the Lord we are OK.
Alfred

 

Here's the thread I was thinking of, FWIW

https://www.jaguarforums.com/forum/x...erving-108372/

Cheers
DD

 

this is from plums about a year ago and explains why my old corvette done a 360 traveling down the road as I hit a small dip in the road that had about a 1/2 inch of standing water in it!
Alfred I saw your post there also it's ironic that nearly a year later you would lose your car to this very thing!

Randy

The condition is somewhat obscure and relatively new because it does not apply to fixed live axle rear suspensions. It took a lot of searching to find the cause and solution after a particularly scary drive on slush over black ice on the highway. The little gem was finally located in a single thread on a automotive board in Canada ... the home of winter slush. This led to refining search terms to find more information. Most of it came from northern areas with a lot of snow. But, still not a lot of hits.

On a live rear axle the tires point straight ahead at all times ... provided the axle has not been bent or twisted.

However, on a independent rear suspension with adjustment provisions this is not usually true. There is usually some toe-in on the rear suspension. This toe-in or even worse, toe-out, will tend to push the rear end from side to side when the tire grip is not even in low traction situations. Each tire is fighting the other to be in the natural straight ahead position. If one gets the upper hand, the other is in worse position and will fight harder to get to straight ahead. The wobbles in the rear is the result of being a witness to the ebb and flow of the fight.

The solution is to set the rear toe-in to zero or just a hair in and exactly equal on both sides. Never toe out ... at least on Jaguars.

Doing the above requires either very careful DIY, or a custom four wheel alignment. "in spec" is not good enough as the spec is quite wide. I chose diy.
__________________
2001 X308 SC

 

As previously pointed out, the wider the tire the more likely it is to hydroplane even with decent tread remaining. Just gotta slow down during periods of heavy rain. Glad to hear that you're okay....

 

Michelin sells about a dozen different tire designs with 'Pilot' in the name. I guessing some are better in wet conditions than others

Just out of curiosity did you ever have the rear suspension toe setting checked as mentioned in the other thread?
Has anyone?

Not very comforting but the angle of impact plays a role in air bag deployment. If the impact was somewhat less then 'head on', the system might not have triggered....by design.

Agreed

Cheers
DD

 

I had a similar (I guess) situation which was very noticable in winter as the rear would break out quickly and on certain wet patches as you say. For me that was a misalignment, after that was set right (can't remember though, possibly to much toe in at the rear).

 

Thanks Doug and V8deuce for the details that I was trying to remember. I did have the alignment adjusted when I put new shocks on the rear but other than being "on spec" I really do not know if any + or - toe was still present. Certainly something I will be **** about if I replace the car. At this point I'm still reacting emotionally to the event so the voice in my head is saying "buy a hummer!"
Alfred

 

I hate it happened to you but you can be in a hydroplaning incident at anytime there's water on the road. Sometimes it's a fluke... Sometimes it's tires.. Sometimes it's driver error... Sometimes who knows...

That's why it's called an accident. Fortunately no one was seriously injured..

 

In decades of driving I've experienced hydroplaning exactly once. Pure youthful stupidity. It left *quite* an impression on me. I was driving wayyyy too fast for the conditions. I saw standing water on the road ahead but there was just no way to slow down soon enough. I hit it the blink of an eye.

Next thing I knew I was all over the road at 70 mph. Felt like driving on grease. With literally zero traction there really isn't any conscious regaining of control. It's just a matter of gritting teeth, holding breath, and waiting to slow down enough for the tires to touch the pavement again.

I was southbound on the Pacific Coast Highway in Malibu, north of Topanga Canyon. Rainy December night in 1979. I was driving my 1973 Pontiac Grand Am. Maroon. Black interior. Fleetwood Mac on the tape deck.

Lesson learned and never forgotten. I've made it a point, successfuly, to avoid a repeat experience.


Cheers
DD

 

The twitchiness is excessive toe, in or out, in the rear. So I run as close to zero as I can achieve by measuring with a laser. (I can measure down to 0.05 degrees although the adjustment cam becomes very touchy.)

Twitchiness is not necessarily hyrdroplaning although it does indicate a lack of traction. A commercial pilot explained here last year that hydroplaning is completely dependent on tire pressure. He was adamant about this and the information checked out at other sites. The limits were surprisingly high.

 

Hey Doug,

During your hydroplaning incident near Topanga in 1979, was that Fleetwood Mac album on the tape deck "Mystery To Me", "Heroes Are Hard To Find", or "Rumors" ?

Glad you were okay, by the way....

 

I think he was listening to Paul Simon .. Slip Sliding away !

 

Rumors ! I didn't own either of the other two

Cheers
DD

 

I don't quite understand. Can you elaborate or find the old thread?

Hydroplaning will only occur at certain tire pressures...or....?

Cheers
DD

 

Sure.

The assertion is that the onset of true hydroplaning is completely determined by tire pressure and completely independent of other factors that we might expect such as tread depth, profile, and design. The member pilot mentioned that pilots use charts or calculations for this based upon the tire pressures carried in the landing gear. He also pointed at the study done by NASA JPL as a reference. Or maybe I found it afterwards.

This is why I made the distinction between lack of traction and hydroplaning.

Bear in mind that aircraft carry tires that have at most a bunch of longitudinal grooves as tread, that the pressures are much higher, and the speeds at landing are also higher.

When I checked the charts against the 35 psi that I use, I think the limit was something like 50'ish mph. If I reach back into the gray cells, that seems about right. I have skidded in water below 50 mph, but I would not call it hydroplaning because there was always some traction ... just not enough. The difference in my mind is that there was always some degree of steering and braking control ... it just took a very delicate touch to dance at the edge.

One way for an experienced driver to figure out how much traction he has is to do a few weaving motions. The pucker factor will quickly tell you whether you are at a safe speed. This used to be a habit any time the pavement was not bone dry. A more exaggerated weave is also useful for getting rid of tailgaters.

The four times I have spun a car on the freeway had nothing to do with water at all ... black ice was the culprit. One of them was a 1973 Pontiac Trans Am which was otherwise excellent in snow. Never had a set of winters on that or most vehicles.