Assuming that you are driving at 100 km/hr speed; your main line program (the loop function) will be interrupted at every 73 ms (1/((491100)/(6060))) interval. Have you thought about this -- your MCU/loop() function might not like these kinds of frequent interruptions. They are machines; but, we have induced intelligence into them through programming; they might get tired/fatigue like human beings and ultimately end up with catastrophic breakdown.
You may check your system by simulating interrupt signal at every 73 ms. If you are not happy with the performance, you may think of assigning a counter (TC0/TC1/TC2) to accomodate so many wheel revolution pulses; read the count via interrupt strategy or polling strategy (I would prefer polling!).