Have a 2014 Lexus IS 350 AWD, my rear tires are still in excellent shape and was wanting to replace just my front tires which are quite worn prior to winter. When I called tire rack the employee heavily recommended against just replacing 2 tires with an AWD system as it could lead to bigger problems down the road as its monitoring grip characteristics etc constantly which will lead to problems if the tires have different tread patterns.

Was he just trying to upsell me or does he have legitimate arguement? My current tires have a massive tread depth disparity between front and rear currently with no apparent issues

 

 

I had a similar situation recently due to inner tire wear on the fronts. The service adviser at the dealership said I could simply replace the fronts, but he "personally wouldn't".

I think it's fine to replace the fronts as long as they are the same model of tire. i.e., if you have Bridgestone Turzanza EL400-02 on the rear now, you should use the same tires for your replacements. I agree to an extent with the Tire Rack guy - for me personally I'd prefer to replace all of them especially if they are the OEM tires just to get into a better set. However, our cars eat front tires for breakfast, so it may not be cost-effective to replace all four every time.