it depends on where you drive it. the mashers are alot bigger, if you have a weak engine i wouldnt suggest them. if your current tires are still good you should wait untill you wear those out. if you drive on pavement that should be about 2 tanks. i ordered some trc park tires recently because i drive alot on pavement. oh and for the front you should keep the ribbed tires unless you get mashers then id go with the mashers in front also.