Not bad if your tires are in decent condition. Replace them when the tread depth drops to 4/32", if you are concerned about wet weather traction. (The legal limit is 2/32" but that is unsafe in wet weather.)
Ive had no problem at all. Where I do have a problem is in the wind. The Prius is very susceptible to wind gusts on the road. Rain alone, no problem. Rain w/wind...still not a problem but you will be holding tight to that steering wheel during wind gusts!!
The only thing between your Prius and the ground is the tires. Good tires are essential to good handling in slippery conditions. If you're even slightly doubtful about your tires, it's time to replace them... a set of tires is much cheaper than a wrecked car or a trip to the hospital. Since the Prius is a front wheel drive car, it has an advantage over rear wheel drivers in that it is a lot more forgiving in slippery conditions. Coupled with the Prius's traction control, you shouldn't have to worry unless you're doing something stupid... no amount of safety features will make up for bad judgment.
*This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.
The strait line stability of the Prius is greatly improved by going to a wider section tyre and raising the tyre pressures. I can only guess how the US version handles in the wind with it's narrow 185 section tyres and the high side walls with 15 inch rims (except touring). The UK/European Prius come with 195 section tyres on 16 inch rims and that does not handle side winds well, but going to 205 section tyres really does transform the car. This in theory should reduce the MPG figures but I find that is not the case. Going on to the OP's question with good tyre treads I have never had a problem with wet or even deep puddled roads.
And if you get an upgraded brace may I suggest you give away or sell cheaply your stock brace to a Gen II owner that doesn't have a brace (If I remember correctly they fit). I know for sure my Prius doesn't have one yet.
This is a double-edged sword. Raising the tire pressure can reduce the contact patch, hence reducing traction. Not something you want to be doing in the wet.
But if you go to wider tyres you increase the contact patch, and there are those that would argue that by decreasing the contact patch you lesson the chance of aquaplaning, so bit of a balancing act.
Taking your statement to its logical conclusion, we can eliminate the issue of aquaplaning by driving cars that don't touch the ground at all.
Thanks for the credit but it's not me. It's called "linear correlation" and it's been in use since the 1850's.
Rain tyre - Wikipedia, the free encyclopedia You want a wide tire in dry weather, you want a smaller tire in wet weather with large v pattern blocks to channel water. In snow, a smaller tire with lots of edges to paddle through snow. Are You Looking to Get the Best Wet Traction and Hydroplaning Resistance from Your Tires? - Choose the Best Tires with Zig | Tire Rack
Raising the temp does reduce the contact patch (if overdone), but it opens up the grooves which is ideal for water channelling and wet weather traction. this will be more of a problem if the tires don't have much groove any more.
I had to drive through wind and rain on the highway under hurricane affected weather recently. My 2009 with stock tires at ~ 50 psi did not feel different in handling than under normal dry conditions. I wasn't trying to do any stunt car tricks though - when people ask about handling I always envision those cars zipping in and out of the lanes trying to speed ahead of everyone else, sorry.
That's just it... if you don't test your car's handling, you won't know how close to the edge of losing traction you are. You may be driving just at the limit without even knowing it. This is why it's best not to play with parameters that affect your car's safety.
