I currently have Goodyear Assurance ConforTred Touring tires on my RX400h. I have had no issues with them. I have been on snow, ice, and wet pavement and the handle great IMHO.
One must remember the the Hybrid Batterys work best between 70 and 80 degrees. So using the vehicle A/C helps regulates the battery temp that is why the vehicle has vents inside and not outside as the first Prius did.
There is an air intake vent under
the rear seats to cooling the hybrid
battery (traction battery). If the
vent becomes blocked, the hybrid
battery may overheat, leading to a
reduction in hybrid battery output
You need to also check your fuel. A lot of States require all grades of gas to contain 10% Ethanol from October to April. If your gas contains Ethanol, then you will see a decrease in mileage, as Ethanol has less energy then regular gas.
It could also be the fuel. In some states they use oxygenated gas which contains Ethanol. This will give you less energy thereby decreasing your gas mileage too.
Took mine in for O/C at 45,000 miles. Dealership while servicing the vehicle, checked the battery, found an issue, and replaced the battery free. Vehicle is almost four years old.
Per my Owners Manual, page 167, states without tow package 2000 lb. (907kg)
with tow package 3500 lb. (1588 kg).
I tow my Bass Tracker Pro 17'7 with no problem at all. My vehicle came equipped with Lexus tow package, receiver, and hitch. B)
See if this answers your questions.
https___secure.drivers.lexus.com_lexusdrivers_my-lexus_resources_download-owners-manual.do_docURI=http___tis.tmsnet.toyota.com_t3Portal_resources_jsp_siviewer_index.jsp_dir=omms_07LexMS_MS0009&href=xhtml_07LexMS_MS0009f.pdf
I just spent three days in Santa Fe, NM taking my son skiing at Ski Santa Fe. There was ice and snow on the road at the top of the mountain. I had no issues with my tires which only have 6,000 miles on them. They are Bridgestone Alenzes.
Page 414 of the 2007 RX 400h Owners Manual states" Premium unleaded gasoline with an octane rating of 91 or higher required for optimum engine performance." It also states"If premium gasoline is not available, you may use unleaded gasoline with an octane rating of 87."
Just remember that the traction battery like in the Prius works best between 70 & 80 degrees. I am currently averaging between 27.8 & 30 mpg here in El Paso, TX. If you just set your a/c to auto, recirculate, and between 74 and 76 degrees you should not see a hit IMHO. B)