Prius scary to drive in heavy rain!!!

<div class='quotetop'>QUOTE(newkbomb @ Dec 22 2006, 10:37 AM) [snapback]365637[/snapback]</div>

I haven't noticed hydroplaning in my Prius and I've driven in a couple bad rainstorms. What's your tire pressure set to? If you are using higher-than-recommended pressure to increase fuel economy (as many, if not most, on these boards do), you should be aware that your traction will also be noticably reduced in certain situations. I used to set mine at about 40/38, but after awhile I got sick of the traction control cutting in every time I hit a big pothole or a small amount of loose gravel. I find there's a lot more traction available when I use Toyota's recommended 35/33. To me, a couple extra MPGs isn't worth not having every bit of available traction in a potential emergency.

 

I didn't have that much experience with the stock tires, I swap them out base on all the negative reviews on PC. I got the Goodyear Comfortreds. I don't have any problem with HEAVY rain at all. Others have used Hydroedge with good results.

 

Reducing the tire pressure, at least down to some point, may give better traction in certain situations as sumi's_man said, but I do not think wet pavement is one of them. From what information I have been able to find the opposite may be true. Tires will hydroplane sooner with less pressure.

Higher pressure provides a smaller footprint which means more weight pressing down per unit area which tends to force the water out away from the contact patch. For the same reason wider tires on the same car will also hydroplane sooner.

 

I have the stock tires (but will probably get around to getting winter tires sometime next week), and I think the Prius handles wonderfully in the rain (of course my last few cars have been weigh-nothing subcompacts, so my comparison is different).

 

here on the west coast where we average 1220MM of rain (4 feet for the non metric litterate) the stock Goodyears are p**s useless on wet roads. I put a set of HydroEdge on her car and what a difference. First the car actually tracks and the wet road performance makes it into a normal car. No more TRAK kicking in on wet and sand covered pavement. Slight hit on the mileage but for making the car safer I couldn't care.

 

<div class='quotetop'>QUOTE(newkbomb @ Dec 22 2006, 09:37 AM) [snapback]365637[/snapback]</div>

I bought my 06 last April and was unhappy with the way it handled on wet pavement. I decided I didn't want to go into a Chicago winter with the original tires. After reading a number of tire threads on this forum, I purchased a set of Goodyear Tripletreads; I've had them about a month. The first rainfall with them, I drove around in an empty parking lot to see what it would take to put the car in a skid. They are a huge improvement! And I'm pleased with the way the car handled our first major snowfall.

BTW: My Integrities had only 5k miles on them - I received a trade-in credit of $15 per tire.

I think that how you feel about the handling in rain depends on what you drove pre-Prius. I traded in a Subaru Impreza AWD that handled great in all kinds of conditions. My husband, on the other hand, drives a Camry and he wasn't as bothered as I by the Integrities. He says that the Prius with the TTs handles way better than his Camry. What I'm trying to say is a lot depends on how you drive and what you expect. Me - I'm really glad I upgraded tires!

Mary

 

My new set of integrities seem to do just fine in heavy rain,
although the drawback is that they're *so* good at pushing water out
to the sides with that directional chevron tread that they pull more
energy from the car to do so, and MPG really gets whacked in the
wet stuff. On dry roads at proper pressures they seem to roll
just fine, though.
.
_H*

 

After all the years of pressure debate, no one has ever presented data showing that softer tires increase traction for a real-world car in real-world situations. Basically, tires of today hold there shape well under a much wider range of PSI than in the past.

I upgraded to HydroEdges years ago, so traction became far less of an issue. In fact, yesterday I got to use them on slush and a slippery driveway. All was fine... though I did use the floor-it side-side feature. Dropping the pedal all the way while on an snowy incline will cause the front tires to rapidly alternate traction. It's something I believe unique to our hybrids, that has proven rather handy.

In short, you can't go wrong with an upgrade like HydroEdges.

 

I had my second set of integrities siped and have no problem with hydroplaning with 42/40 pressure. We have a lot of wet driving conditions here in the Northwest.

 

In heavy rain I slow down and as such I tend to have no problems with hydroplaning regardless of what vehicle I am driving as long as it has legal street tires with plenty of tread.

 

<div class='quotetop'>QUOTE(newkbomb @ Dec 22 2006, 10:37 AM) [snapback]365637[/snapback]</div>

I would like to disagree with the majority opinion regarding high tire pressure and wet pavement. I think it depends on the car and tires.

I performed the experiment with my Ford Escort, which at that time had low-rolling-resistance ("gas-saver") tires. Which, I as I understand it, are not the grippiest of tires even in the best of circumstances. The tires were practically new -- a few K miles on them at best. At 5 PSI over the recommended pressure, the car was all-but-impossible to steer on smooth wet pavement. Downright dangerous on (say) a highway offramp. That's a true pre-post analysis -- same car, same tires, only one change, huge difference. I put them back to recommended pressure, problem solved. So, for some tires and some cars, yes, modest overinflation of the tires can significantly comprise steering on smooth wet pavement.

Having said that, I've noticed no loss of wet-pavement control on my Prius with 42/40 inflation. Or course, I drive way far away from the limits of stability on the car (ie, I drive like a little old lad)y, and I have no complaints about the stock tires (they're like round 'n' stuff, that's good enough for me), so I'm probably not the best test case there.

Do people really trigger VSC/traction control/ABS on a regular basis? Annoys the heck out of me when that happens. If anything, the electronic controls make me drive more conservatively, to avoid triggering them off. I figure that if I used those all the time, that would mean I was driving too near the limits of control of the vehicle. I figure they're for emergencies, or something.

Also,contrary to the original post, I don't think the Prius is a particularly light car in any sense that matters here. It is both reasonably dense (lbs/cu ft) and, to my eye, with the stock tires, has as much or more weight per tire contact area (lbs/sq ft) as any other car I've ever driven. Haven't tried it in snow, but have had no problems with rain and wind.

 

<div class='quotetop'>QUOTE(maryi @ Dec 22 2006, 09:22 AM) [snapback]365689[/snapback]</div>

My experience is very similar. Before replacing the stock crap Goodyear Integrities, I had all kinds of traction-related problems when the roads were even just slightly damp. Traction control would kick in every time I drove away at a green light.

Since switching to a set of TripleTreds, I have yet to activate the traction control. If the stock Integrities perform so poorly given the mild weather we have in Northern CA, I can only imagine how badly they behave in more severe weather.

 

<div class='quotetop'>QUOTE(tumbleweed @ Dec 22 2006, 11:37 AM) [snapback]365661[/snapback]</div>

I don't agree. The idea is to have the entire tread contacting the ground so that its pattern can direct the water to the rear and sides as designed. By overinflating the tires, you are indeed decreasing the area of the contact patch (which does, as you suggest, increase the pressure on the road per inch squared), but you're also compromising the design of the tread, by lifting the edges off of the road.

I think it's pretty obvious that the forces involved with hydroplaning are immense; while your suggestions hold water (if you'll pardon the pun) on a theoretical level, practically what you're suggesting is a net loss, not a net gain in traction.

I'd humbly assert that, in wet conditions, tires with new or a reasonable amount of tread left will resist hydroplaning best when the pressures are set near the manufacturer's recommendation.

 

<div class='quotetop'>QUOTE(Pinto Girl @ Dec 22 2006, 12:50 PM) [snapback]365794[/snapback]</div>

I wish we had some good objective test data so we could know for sure what presures are best. It must be an interesting curve with less traction at the high pressure and the low pressure extremes and the area we are interested in somewhere between. Driving the car and saying "well it feels like more traction at this pressure" is far to subjective unless it is really bad.

Increasing the pressure by the amount we are suggesting here definitely won't lift the edges of the tread off the road. I think it will shorten the contact patch slightly in the direction of travel but it will also hold the tread open better so water can drain more effectively.

I think manufacturers tire pressure recommendations (for most cars) are weighted toward a nice soft ride rather than fuel economy or handling.

There are some excellent photos by Hobbit (I can't find them right now) of a set of Prius tires that were run their entire life at Toyota's recommended pressures. They are badly worn on the edges indicating the pressure was to low.

 

<div class='quotetop'>QUOTE(newkbomb @ Dec 22 2006, 07:37 AM) [snapback]365637[/snapback]</div>

There is a VERY simple solution, and it applies to every vehicle driven on wet pavement. SLOW DOWN. Water acts as a lubricant (as well as a planing support).

I know what hydroplaning feels like, and it ain't fun. Since the carefree days of my mis-spent youth, no matter what car I'm driving, I have managed to avoid hydroplaning by simply driving at a safe speed for the conditions.

<div class='quotetop'>QUOTE(tumbleweed @ Dec 22 2006, 03:03 PM) [snapback]365843[/snapback]</div>

Thanks for saving me the trouble of typing all this! Very well said. And I agree, if that counts for anything...

 

It rains plenty in Puerto Rico. I have had no problems with hydroplaning with either the stock tires or the Goodyear Viva2s.

 

I still have the OEM tires on mine. One month ago I drove to my family's residence down near Wilmington as they were having tornados that had just killed 9 people. Needless to say the rain was a nightmare. I felt very secure in the Pruis. No wobble, no slide, no hydroplane at all. Again this evening we drive from Raleigh home in a very very heavy downpour. Again, no problems with hydroplaning, although visibility was terrible, no wipers on any vehicle would have been able to go fast enough to clear the windshield. Just my experience. If I had been experiencing hydroplaning, with my family in the car I'd switch 'em out in a heart beat, but so far, no worries.