Finally got my wheels off and did some measuring.  This is from a 2002 4dr V6 tracker ZR2

Wheels:
15 x 6
4" backspacing

Inner Diameter at mounting surface (clearance)
13.25"

Diameter of rotors + calipers
12.75"

Leaving 1/4" of clearence all around

I was going to see if someone would take measurments on a GV to see if they are the same, but I looked up replacement rotors, and they are not the same!!!!  From NapaOnline.com

Rotors for a 2002 Tracker

Item#:  UP 86927
Attributes:
# of Bolts / Holes:5
Brake Rotor Type:Rotor
Discard Thickness:.591"
Height:1.145"
Outside Diameter:11.290"

Rotors for a 2002 GV

item#:  UP 86922
Attributes:
# of Bolts / Holes:5
Brake Rotor Type:Rotor
Discard Thickness:.787"
Height:1.140"
Outside Diameter:12.195"

Since the GV rotors are almost 1" bigger, there is no way that Tracker wheels would fit.  Several people have suggested that, but has anyone actually tried it?

.....

On a hunch I checked and found out that the rotors for the Tracker are the same as the ones for the base model Vitara.  Apparantly the Tracker has the same brakes regardless of if it has a 4 cylider or V6.

out

The main problem is the caliper hits the backside of the wheel.

Josh

Do you mean the calipers hit the back of the spokes, and not the inside of the rim?

Well then here is a stupid question: If I had to replace the brakes, could I pick up the Tracker rotors and calipers to fit the 15" rims?

If the V6 Tracker has the smaller rotors and calipers then the stopping power can't be much less.

RustyRed

tried 15" wheels on a 2003 GV, the calipers toouch the wheels, see here

http://www.offroading.net/html/projects/gv.htm#wheels