When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I finally managed to figure out how to replace stock 21" wheels with something suitable for off-road. I figured this info may be useful for other LX owners.
It was almost impossible to find wheels with the same offset and lug holes configuration as the stock wheels (5x60). I did not want to mess with spacers or modifications. There are stock 18" Lexus wheels that could have worked, but they are extremely unremarkable, so I picked the Toyota TRD wheels (p/n: PT9603420002): PT9603420002 - Trd 18 forged bbs matte black alloy wheels - Genuine Toyota Accessory
These wheels are for Land Cruiser / Tundra, but they have the same offset and lug holes configuration as stock LX wheels, so it was a perfect match.
I also needed TPMS Sensor Fitting Kit (p/n: 04423-33060), to get new sensors installed in TRD wheels.
As for the tires, I picked Michelin LTX AT2, but was not able to find any in stock, so bought BFGoodrich T/A KO2 LT285/65R18/E 125/122R (32.6") instead.
Here is the result (suspension set to "Low"):
These tires are subjectively noisier than the stock ones, but not to the point where it becomes uncomfortable. No rubbing whatsoever.
There was no issues mounting the spare wheel.