What wheel spacing does the GTM use?

[scottvette1989]

Is the spacing the same as a C6 Corvette? I don't have an GTM yet but it is coming in the near future.
Scott

[Kempo]

Here is a copy/paste of the wheel and alignment specs posted by FFR. Hope this helps and welcome to the forum.

Front Size: 8-9.5
Offset: 50-65 mm
Backspace Equation (inch): (width/2)+2.5
Tire Size, 245/45/17. 245/40/18

Rear Size (275-295): 9-10.5
Offset: 40 mm
Backspace Equation (inch): (width/2)+2
Tire Sizes: 275/40/18, 285/40/17, 295/35/18, 295/30/19

Wide Rear Size (305): 11-11.5
Offset: 46 mm
Backspace Equation (inch): (width/2)+2.25
Tire Sizes: 305/30/19

Extra Wide Rear Size (335)” 12-13
Offset: 52 mm
Backspace Equation (inch): (width/2)+2.25
Tire Sizes: 335/35/17, 335/30/18

Notes:
1. Wheel width is the advertised width measured at the tire bead
2. Factory Rear wheels use spacers provided with 275 tires for best fit
3. Max. recommended tire diameter is 25.9” (from 335/30/18) – fitment of larger sizes is unknown and not recommended.

GTM Alignment Specifications

Front:
Toe In (inches): 1/8
Camber (deg): -0.25
Caster (deg): 2.5

Rear:
Toe In (inches): 3/16
Camber (deg): -0.5
Caster (deg): N/A

[VRaptor SpeedWorks, LLC]

It's designed as a "one-donor" car (with the exception of the Porsche trans), so it is designed to accept the C5 wheels with the supplied spacers for the rear wheels. If you are not using the spacers and having custom wheels made.....I'm not sure if the info above is for use with or without the spacers. The offsets that I've used don't exactly jive with what FFR has in that post above.

[scottvette1989]

Thanks for the info guys.
Scott

[dreabrown]

I'm thinking about running 335/30/18's on the rear with the Forgestar rims FF sells. Anyone out there running this combination? How does it handle? Any tips?

Thanks