you might be talking about "the clunk". if you tap the accelerator sharply back and forth while in gear (especially in higher gears) you will get a loud 'clunk' from driveline slack, which is normal for terminators. if you lay into the pedal differently, either softer or mashing it, you cant hear it as much.
i dont see how the new drag radials are now causing a problem you aslready didnt have though.
if you already know what this is and your sound is something else, than maybe what others have said..