Is Rx330 A True Awd?

[i-spy]

Hi,

I am interested in the AWD version of the RX330 and wonder is it a true AWD (like ML and X5) or just FWD most of the time (like MDX).

Thanks!

i-SpY

[wwest]

I can only guess how it's done but my AWD RX300 registered 95/5 initially on a 4 wheel dyno. After we forced the rear wheels to lag the front via braking the rear dyno only it did go to 75/25. The change was obviously due to the viscous clutch in my 2001.

The 2004 and later RX330s don't have a viscous clutch just a simple open diff'l in the center. The RX330 uses the braking to apportion engine torque should a driven wheel begin to slip.

My guess is that Lexus and Toyota (HL) use the different final drive ratio in the front versus the rear to attain a higher level of engine torque in the front versus the rear.

Additionally the RX, HL, and Sienna cannot have snowchains on the rear due to close suspension/tire sidewall clearance. While clearly acknowledging the hazardous nature of higher roadbed traction on the front vs the rear in their own owners manuals they then recommend snowchains be used ONLY on the front.

My 2001 AWD Rx300 has 1.5" wheel spacers all around, 17X8 wheels and 235/65-17 Bridgestone Turanza EL30 summer tires. I choose the tires mostly for quiet running. My answer to winter conditions is to always keep snowchains (two sets) on board during the winter months and do not hesitate to use them.

[Booyah]

I dont know the specifics of the AWD system in the 330, but I can tell ya I had NO problem at all in the Feets of snow we got last winter--it was great.

[wwest]

Booyah:

I never had any problem driving around in "feets" of snow in Alaska or Montana even with RWD only. It's the packed snow and/or ice that always caused me to install the tire chains.

Now tell us how it did when the roads in Alaska are perfectly smooth, say in the early spring when the ice thaws during the day, fills all the potholes and then freezes overnight resulting in a perfectly smooth, but extremely slippery roadbed.

Studs or chains?

Personally I NEVER want to experience any FWD, or front torque biased AWD, in adverse roadbed conditions, way to hazardous for me and mine. Absent off-road, which I don't do, I'd op for RWD and a good set of snowchains anytime over any AWD, or 4X4 without them.

Remember that DRIVING all four wheels gets you up and moving from a stop, and provides better overall traction for acceleration, but what have you done to help you stop or turn.

If the traction surface is so marginal that you really need AWD or 4X4, remember that doesn't change the fact that you rely, really, on only the front wheels for turning and stopping. Adding engine drive traction, or even engine compression braking, to the front wheels will always reduce the level of traction available to maintain directional control of the vehicle.