Improving emergency braking performance in raining condition

(1) What tires do you have? If original, they may be due for replacement. If they have already been replaced, the brand and model may give some tires guy here a clue.

(2) What is your tire condition? Miles, or tread depth, or some form of description to tell us how much wear they have experienced?

(3) What air pressure is in the tires? Low pressures are more susceptible to hydroplaning.

(4) Did the Brake Assist or ABS or Stability Control trigger in this very wet condition? If not, you may not have been applying full brake force.

 

As far as comparing LRR tires, check out this article from Tire Rack about their testing of different LRR tires.

 

49 psi probably exacerbated the problem. if you're serious, you probably need to replace the tyres with some good stopping power. and lower your psi to 42/40.

 

YIKES.

No doubt in my mind that your excessive tire pressure probably played a small part in the problem that you (almost) had.

I personally do NOT believe in exceeding the book recommedaion more than 5 LBS or so because more than that changes the tread's perfoamance characteristics too much.
(Others will no doubt disagree with that.......without any real proof to offer.)

A panic stop on a road with less than ideal traction is a crap shoot.
Even with ABS, a little hydro-planning could have occurred.
If the shower was brief, there could have been a slight oil slick.

I think it is likely that there isn't much that you CAN do to improve things in that kind of situation.........except maybe slow down and re-think your rock hard tires.

On a clean, dry road, wider tires might be better.
On a wet or otherwise slick road, they might be a tad worse.
It is impossible to eliminate all the bad possibilities.
Worrying about it won't help either.

 

i've never run anything but the stock tyres and wheels. perhaps someone with experience can help, or you might try searching tyre and brake threads. all the best!

 

i've never run anything but the stock tyres and wheels. perhaps someone with experience can help, or you might try searching tyre and brake threads. all the best!

 

excessive tire pressures baloon your tires. You dramatically decrease the contact patch area. Grip, especially wet grip, is dramatically reduced. Do not exceed the recommended pressure by more than 5 pounds as said here. The ride becomes harsh, grip drops and wear and rattles increase. All for your 1mpg. That accident is not worth it. Even more important, avoid cheapo (chinese) tires. Always get known brand tires with a high silica content. This gives you the wet grip. High silica means higher price, unfortuantly. Cheap tires improve dry grip via soft rubber. They do not last and will scare the shit out of you in the wet. High silica tires dramatically improve grip while using harder rubber. So they last longer, have both wet and dry grip, but cost more. There is a reason cheap tires are called ditch finders. The Prius OEM braking system can get your tires to break traction even at highway speed. So no need to upgrade pads or such bits. Wider tires improve dry grip, but increase the risk of aquaplaning. Your mpg will drop as rolling resistance goes up. Wide rubber beyond a certain width vs. diamter also tends to tramline. This makes highway driving tiresome. A very good tire in the upper price range will offer more braking performance than a budget wide tire and last longer. But you safe the expense for wide rims.

If you rely on top braking performance, get one of the top 3 tested tires. LRR has a small drop in performance, but the trade if is mainly in comfort. LRR tires are rather stiff.
Marko


So drop that pressure and try again.


iPad ?

 

LA area? Insurance scam attempt?
Want to improve your wet surface braking? Tyres tyres tyres. Overinflation will help mileage but not traction.
Get good wet weather tyres and inflate to proper levels. You can go 15% over Toyota recommended value and not affect traction. Much more than that will.
I like Nokian WRGIII tyres and inflate to 40 front, 38 rear. They are "all weather" and also LRR.

 

So the op has no name tires over inflated and hydroplaned
I agree, good rain tires and 40ish psi will be safer in deep water, and let me be so bold as to say 40ish is better than 30ish for air pressure in this instance, the higher pressure is more responsive at both turning and stopping.Yes the op could go to 17" wheels with 45 series rubber but why give away 3-4 mpg's.

 

High pressure reduces hydroplaning, not increases it. That is according to the aviation and NASA sources that have studied it. I learned about it after discovering that a previous car's recommended pressure was too low for my rainy climate.

But that doesn't cover wet grip absent hydroplaning, which is a separate issue. Despite plenty of strong opinions, I've seen no consensus on this.

 

You can't make THAT flat statement either......as the effect of higher pressure on the tendency to hydroplane depends almost entirely on the tires construction and tread pattern.

All other things being equal, a narrower tires has less tendency to hydroplane but it is not a guarantee that higher pressure will create a smaller contact patch.

 

To give you more shorter braking distance? To give you more cornering grip to swerve away from a hazard? To avoid the trauma of a crash? To avoid injury in a collision? To avoid the headaches of dealing with insurance? To avoid the inconvenience of not having your car when its away for repairs? ... to save some tiny amount of money?

 

Double post

 

get proper rubber with a good wet traction rating (high silica content = high price) and dump them after 4-5 yrs the latest. The rubber gets hard with time and grip gets worse. Wear actually goes down. So folks tend to use them forever as there is still thread left. Wnna kill yourself, get cheap chinese ditchfinders witha 60000 mile warranty. First drop of rain and you think you're in a sled on ice. There is a reason good tires cost serious dosh. Dry grip is not an issue anymore except for the most bizzare brands. On wet roads the differences show. Some budget brands compensate lower silica content, high silica =? high wet grip) with softer rubber. The price you pay is wear rate. So medium priced tires with good wet grip wear fast. Higher priced tires tend to offer both wear resistance plus grip. You pay your money. Buy cheap, slide twice.


iPad ?

 

Overinflater or not, this is how ABS works. Allows you to steer around obstacle. Sounds normal to me.