FamilyRX

We just had a snow storm leave 6-10" which has literally shut down the city. I know in other parts of the country this is just a nuisance but it is a big deal here. I wanted to find out how well the 450h does in these conditions as the AWD system is "not for off road use".

Our RX has the 19" wheels with Bridgestone tires. For those unfamiliar with the 450h's AWD system it uses an electric motor to drive the rear wheels. There is no driveshaft from the front and no locking differential like the RX350 AWD. It does have a Hybrid Snow mode, although it must be reactivated every time you restart the vehicle.

Most of the roads here are flat with some slight hills mixed in. The RXh did extremely well, not getting stuck once. There were a few times where I felt it lose traction but maintaing a steady speed and throttle application moved it through without drama. After a while I was deliberately looking for unplowed streets to see how it would do. Again, the RXh had no problems.

Overall, the car did great, although having prior experience driving in the snow does help. There were MANY people on the roads who did not have a clue how to drive. I also believe that if the snow was much deeper than it was, the RXh would not have done as well due to its tires and lack of locking differential. It is comforting to know that it can be used in these conditions if necessary.

Next test? The beaches on the outer banks of NC.

vlad_a

Although the system performs very well in slow speeds, it does revert to FWD when cruising. I did not like that when driving at higher speeds on snow covered highways. And I have a dedicated snow tire set.
I also managed to miss a couple turns into parking lots due to longer stopping distances. Got to remember, it is a heavy beast. Other than that, it also performed well for me as well. Unplowed roads are not a problem at all.

I wouldn't take it to the OBX, though.

GRMick

IMO, it's not the system but the tires that determine the performance.

We mounted Nokian winter tires and out RX 450h is just been unstoppable even though it doesn't have a full time four wheel drive system. The system has done just great here in Michigan. The four wheel drive kicks in where we need it, to get started, and then front wheel drive is fine.

dug320

Experience and tires is important driving in the snow. But, weight of this vehicle sure makes it interesting. Plow wash is flattened with ease.

One of my complaints with the drive system is the lack of power in reverse and this becomes an issue when trying to extract the vehicle when stuck or when momentum is lost backing up a steep incline.

vlad_a

Have you tried turning the traction off? That's what may feel like a lack of power.

Droid13

My only complaint about how it handles in the snow is the noticeable understeer going around 90d corners at other than dead slow speeds compared with my FWD vehicles. Even this year with new snows it didn't make any difference. I'm not sure if it's weight, or the rear wheels providing some push, but I often have to fully turn the wheel before it will even begin to turn and when it does it goes from no turning to full turning fast. I've been trying to train myself to give it a bit more gas to see if the front tires will bite better to initiate a turn, but it's hard to want to step on the gas more when it starts sliding out straight forward while in a turn.

Because of that I'm always a little extra leery going around curves on snowy roads at cruising speeds, but so far it sticks fine in those situations.

jrfiero

Who knows what the Hybrid Snow Mode does?

Jonas

vlad_a

Jonas,

It retards throttle response a bit and keeps rear wheels engaged more aggressively.
Not sure if it has any effect on the VDIM system.

kitlz

Jonas, snow mode is similar to starting in second gear. Lexus has had it on the RX since it came out. I can count on my one hand the amount of times I've used it. Having driven manual for the first 10 years I don't like the feeling. Instead I keep a light foot and upshift or downshift as needed. It gives me more control IMO.

FamilyRX, great story. I have had many adventures myself too in 15 years driving the RX. Not stuck once. And I'm sure your RXh will enjoy the beach more than the snow. Stay safe, we have a way to go yet before winter's over.

vlad_a

Anita,

I will challenge the 2nd gear theory. It came up many times on the IS forum, however, I'm fairly certain the Auto IS I used to have always started in 1st. Needless to say, the hybrid has no gears, so it's a moot point.

kitlz

vlad, I said it feels similar to starting in second gear, not that it actually does.

Droid13

I use it all the time, even on simply wet cold roads (ie salted roads below freezing). I find it noticeably reduces front wheel spin and subsequent traction control activation, actually making the vehicle feel more responsive.

kitlz

Andy, I was told by my sales guy not to bother using snow mode for anything under 6" of snow. I've just not found it to be helpful in my experience. Don't get me wrong, I'm glad it works for you. Now I don't make it point to go out in snowstorms (10+") like I used to. Dealing with all the curves, hills and other drivers around me is bad enough. Add in the huge craters all over the place, UGH! Hill assist is something I'll use if I have to stop on an incline. That has helped me lower the risk of losing traction when starting out. VDIM also works well. I love how it works so seamlessly.

Droid13

Curious what situations you've experienced it and what happened? I've been driving VDIM equipped cars for almost 8 years. The only time I've ever been able to activate it (ie the traction slip flashing light coupled with the VDIM warning tones) was a couple of times on snowy roads when I purposely cranked the front wheels in an open area and stomped on the gas, just to see if I could trigger it. Not really a fair test for me to comment on how effective it truly is. I've never actually had a situation in normal driving that it activated when I wasn't trying to (I guess fortunately, knock on wood).

The comment your dealer made about the 6" of snow thing. I wonder if that is a bit throw back thinking to the good ole days when mfrs recommended part time 4 wheel drive vehicles not engage the front wheels on dry roads. That was because the front and back wheels were gear locked together causing strain and extra tire wear if the front and back did not have independently the exact same rotational speed, which was pretty unlikely. The RX450h is probably as far from that as you can get, the fact that the rear wheel drive is completely independent from the front drive. In my view, Snow Mode is a lot like ECO mode, it's just a slightly different set of parameters to guide the vehicle electronic's logic process.

Without snow mode, if I give it 80% throttle and hold it there turning out of a stop sign on cold wet roads = 80% power, trac activates and momentarily drops to 20% power, quickly back to 80% power, trac activates again more briefly, 40% power, back to 80% power again and by then things settle down as I'm up to speed. Where I get on the highway in the morning it's a short and uphill sprint to highway speed, on slippery days I sometimes get 3 of these wavers in power as the trac continues to adapt to the slippery roads. With snow mode I think just that little extra push from the rear tires makes acceleration more linear, maybe I push it more than most. I actually drive quite calmly in the summer and really try to get the best economy, but in the winter is when I have a bit more fun because I actually enjoy driving in the snow as long as the traffic isn't too bad, and the cold weather dampens my enthusiasm for trying to reach the best economy.

kitlz

Andy, a few weeks ago VDIM activated while driving to work. The weather had changed from rain to snow, causing black ice. I was going down a curvy hill and went to stop in order to make a turn. It was more like an inverted V than a typical turn. The RXh started to skid as I pressed the brake but stayed perfectly straight and under complete control. I know there were a few things flashing on the dash, ABS engaged, and probably some warning sounds too. Stereo was on. I went maybe 10 feet beyond where I wanted to stop. I still was able to make the turn though. Many other drivers weren't so lucky. There were a lot of accidents that day, mostly people skidding into curbs and each other.

I wish I could turn off VDIM to see what kind of difference it makes. In a controlled environment of course, LOL!