What size spacer will I need?!?!

[pokeraddictxj]

Hey guys so I'll be getting some new wheels soon and I want the stance to be equal or close to what I have currently so here's what it is...I currently am running 16x8 et11 BBS RS's and I have a 15mm spacer...the wheels I will be getting are 17x9 et20...

Soooo my question is what size spacer would I run to get the same specs as my current set up? can someone also give me the breakdown of why I need that size?

[Even.j]

So you have a final offset of -4. To get the same inner clearance you will need a 37mm spacer, and your wheel will poke 26mm more.

I used this offset calculator..
http://www.1010tires.com/wheeloffsetcalculator.asp

[pokeraddictxj]

I went to that site...for some reason that seems wrong...thats a HUGE spacer for a wheel thats wider and the offset isnt that much higher...

[pokeraddictxj]

I think I need a 12mm spacer...that seems to make more sense...THANKS!!!

[Even.j]

Well, if you want the same inner clearance it isn't wrong. If you use the final offsets the inner clearance will be the same. 16x8 ET-4 and 17x9 ET-17.

[Even.j]

I think I need a 12mm spacer...that seems to make more sense...THANKS!!!

Ok. Same outer position.

[Tuck&Poke]

lol wtf, 37mm spacer. You need an 11 to have the exact same offset, but that would be custom so you need a 12mm spacer or a 1/2in spacer

[Even.j]

lol wtf, 37mm spacer. You need an 11 to have the exact same offset, but that would be custom so you need a 12mm spacer or a 1/2in spacer

Haha. Thought that since he already was using a 15mm spacer he needed the same inner clearance..
My bad. :P