4wd buggy tires...

[viper7016]

I am about to buy a Durga kit and I am wondering about tires. Why do 1/10 scale 4wd buggies have a wide rear and skinny front, but 1/8 scale uses skinny all around? And I am also wondering if I can use wide rears all around, what are the cons of this? The track I run on is out doors and is like a hard pack clay/dirt with fine dust on it, any tire recommendations that won't wear out quickly would be appreciated too : D