I don't drive my wife's 550 much but have never cared for it's around-town ride. It's excellent for highway driving. Recently we used it on a ski trip and coming home there was a decent amount of standing-water puddles on the parkway. Every time I'd hit one the truck would pull quite hard to the shoulder. So much so that I had to slow down or even ride the center a bit when one approached. The 550 has pretty wide tires in front and I'm sure that is a big factor. I'd guess the 450 would be better but I'm interested in your feedback on this. Was usually driving 50-60 due to conditions...

 

The tires are pretty wide on all models. We had the exact same issues on the stock Michelins on the 320. It is far less on the Nokian WRs we have now. Big problem with the 550, is there are very few 21" tires, and even less with the correct load rating etc. to choose from.

 

Exactly....! I am waiting on my 2011 450 and it is coming with 19" tires and there are not many choices there either! It is indeed the the width of the tires relative to the sipes ( grooves ) ability to displace water. Ironically, the cars of the 1920's went through water and snow better than many of our AWD fat tire cars of today! BUT.... they were no where near as comfortable!

 

We had some heavy rains here yesterday and I happen to be driving it again on mostly local roads. Plenty of flooding and there were no issues up to about 40 mph regardless of puddle size. I guess the answer for highway driving woul be to slow down, but it doesn't seem right for me to have to creep along in the right lane while getting passed by Accords and Camrys not having problems ...

 

It's called hydroplaning...it happens to all vehicles. The narrower the tire, the better it'll track through rain. I use Dunlop's for summer tires on the stock 19's, and they are very good in the rain - compared to all seasons...they seem to displace the water quicker and more efficiently. Then I place a smaller 18" wheel on in the winter months with Blizzacks on them...best of both worlds. Good luck.

 

Thanks for the input, but IT IS NOT HYDROPLANING. That occurs when the sheet of water lifts the vehicle off the roadway and the tire is not actually in contact with the ground any longer. Similar to being on a sheet of ice. What's going on in my case is the tire contacting the puddle is actually being "slowed down" relative to the other three wheels and the net result is a pull or jerk to that spot. It happens on either the front right or left. Due to the width and also tread pattern the tire isn't able to "slice" right through the water like it would if narrower or many more grooves instead of solid rubber. You are 100% right in displacing water which is key to preventing hydroplaning and would also help what I was talking about. Thankfully my wife's driving pattern is very little highway and there isn't a ton of standing water puddles on them or I'd have to do something for safety's sake.

 

Get wet weather specific tires. Even on 295mm wide tires, these will cut through the water better than skinnier tires on regular rubber.

Also, make sure to keep your foot on the gas (not stomp it, just continued light pressure) otherwise your AWD is rendered useless in in help to keep you straight.

 

Excellent advice on the Awd... Chego ve delayt v Grozny?

 

I respectfully disagree. It is hydroplaning. But it is happening on the one side of the car you are hitting the puddle with and then sliding - nearly immediately your awd system is recognizing it and is controlling the slide over the water with light braking to bring it back into control. With the weight of the ride, and higher speeds - it's a dangerous combination on water.

 

We'll have to agree to disagree, but either way it is a disconcerting feeling. I'll ask my wife what goes on in her normal driving routine.

 

I also agree that this is not hydroplaning as the effect can be reproduced at low speeds. Additionally, AWD/braking system intervention essentially amounts to an ESP trigger which does not always occur. While wide aspect tires are perhaps the biggest factor in causing such a "pull", it seems more pronounced in the GL than several sports cars I've driven with even wider tires. I suspect the combination of tire width, ride height, and potential turbulence within the wheel-well all contribute.

Regardless of the the dynamics involved, a few pointers I discovered help mitigate the effect:

1. Stay on light throttle through standing water.
2. Lower vehicle to Sport mode (lower center-of gravity and space within wheel-arches)and/or use the off-road program button (changes transmission and AWD bias).
3. Winter/ narrower width tires as mentioned.

 

With regards to #2 above: When the GL is at highway speeds it is lowered automatically for better drag co., also the off-road option can not be used at high speeds, so that would not be an option here.

 

The transition from normal to sport ride height happens automatically at about 65-70 mph. I mentioned that ride height can be manually lowered, as I'm assuming most folks aren't cruising at higher speeds than this with heavy rain/ standing water. The off-road program is not speed limited, though the automatic lowering function is disabled when active.