jadeboy

iTrader: (1)

I have to replace my front 2 tires (both Pilot Sport A/S) 2254018 on the IS 350 with Pilot Sport A/S Plus.

But other have suggested that I replace the 2 rear tires also to keep the car balanced. These rear Pilot Sport A/S 2554018 has about 10,000 miles on them and seems to be in decent condition, but I have done high performance driving and autocross with these tires.

Should I spend the money and replace both front and back or just the front?

What are the issues if I just replace the front?

mitsuguy

iTrader: (2)

the potential is to have mismatched tire performance, which could lead to severe oversteer or understeer, or very unbalanced braking...

the car is designed around a certain amount of understeer, for safety reasons...
if you put a tire that ends up having more grip on the front, you might make it oversteer, which is less predictable... if you put a tire on that ends up having less grip on the front, it could make it understeer even more... similarly, braking might be affected and ABS engage earlier...

these all might or might not be noticeable, and might not be anything to worry about, but, these are your potential problems any time you mismatch tires...