new lip size confirmation

[Jbpka06]

I currently have 15x7 et38 rs047.

Adding a 2.5" lip will make these 15x9 et13 according to this http://www.1010tires.com/WheelOffsetCalculator.asp

does this sound right? Can anyone back me up on this?

[E30SPDFRK]

What size lip do they have currently? Your math is correct assuming that they have a .5" lip now.

[Jbpka06]

yeah i have half inch lips now and I am going to be buying 2.5s

[E30SPDFRK]

yeah that's right then