salimshah

At the end it is a moving surface and fixed surface "connection"... either in slowing down or trying to go faster. Behind that scene is the force ... spinning or braking and somewhere is the silent "inertia" [weight based].

In scientific terms it is the coefficient of friction and the road-surface, tires and any medium in between (ice/snow/water).

Salim

stumpiesgr

good comeback . . . the issue is one of inertia: a body at rest will not move - because only 1 front wheel spins (snow/ice). if it were a rear-wheel differential problem, i could apply the emerg brake lightly to transfer the load from one side to the other.

Jeff Lange

iTrader: (1)

The same can be achieved at the front wheels with careful brake pedal modulation.

The RX uses a open differentials front and rear. Only the F/R bias is really controlled by the computer, however 3rd generation RX models equipped with VDIM do have an electronic LSD function which will apply braking force to limit wheel slippage. Models without VDIM do not attempt to control L/R bias in any way (mechanical or electrically).

This came up previously in the thread and there was some question as to the effectiveness of this form of LSD. I've seen it used to some decent effect in off-road situations in vehicles like the FJ Cruiser, Tacoma, and 4Runner. On-road the IS F made okay use of it for 2008-2009 before adding an actual LSD for 2010. I am not sure on the exact engagement conditions for control in the RX, but based on my reading it seems to be used more for control through corners than in situations where only a wheel is spinning (from stopped or while driving straight).

Jeff

stumpiesgr

thankyouse ! one concentrated bushel of information you have provided.

gent commenting to his lady, "no idea why you wanted me to put the cake in at 120degrees."
she looking into the oven at the cake balanced against a protractor at exactly 120degrees, "GEORGE !"

CSpecISF

In all honesty, it does sound like the tires are not up to par for the weather you're driving in. I have a 14 RX350 F-Sport that came with the original Michelin Latitudes when I purchased it, it was scary to drive in deep snow as my winter tires hadn't arrived yet. When I changed to my Bridgestone Blizzak WS80s (new WS90s are out this year), the RX was much better in the snow. In addition to the RX and IS-F, I also own both a Subaru WRX (open diffs front and rear, with a viscous centre diff) and WRX STi (LSD front and rear, with electronic centre diff), where both Subarus are also equipped with excellent snow tires. While the RX350 isn't exactly as good as the Subarus are in the snow (to be expected, since it's MUCH larger), it still is unstoppable and easy to drive. I haven't experienced any situations that would thwart ones confidence or cause one to worry about driving in inclement conditions. If I'm honest, the only thing more that I kind of wish the RX did offer to me as a driver is a little bit of extra freedom to be able to throw the car around a bit more in the snow. I just hate how much the nannies on the RX interject, not a deal breaker all in all since I have other cars to have fun in the snow with.

I guess the moral of the story is don't be afraid to pay a bit extra on a better set of snows, you'll be thankful you did. I love the Hankook iPikes and the Blizzaks, both fantastic snow tires.

stumpiesgr

appreciate the response; we are not on the same page. if one wheel spins and the other three do not, the problem is not the rubber.

CSpecISF

Yes, it is. The 1 wheel spinning is due to the other 3 having traction and the 1 spinning wheel not having traction. The only thing between the rim and the driving surface is the tire. The fact that only 1 wheel is spinning is because the RX has open differentials both front and rear, and the path of least resistance is the 1 spinning wheel, where traction between that tire and the surface you're driving on does not exist. Change to better tires and you won't have nearly as much slip due to the improved traction = no path of least resistance.

stumpiesgr

thankyou. specificially; if rubber was the true problem, with only one tire spinning, why would one other tire (RX - different differential) not also spin ? were two tires slipping, i would look seriously at the rubber solution.
with only one wheel spinning, i cannot. i believe the previous suggestion to use brakes to bind the spinning wheel to cause a load/traction transfer to be spot on. unfortunately, that was not attempted (then), so the solution remains only potential.