Wheel Offsets and caliper clearance for 17" Wheels

Vintage Wheel Notes for 17" x 8.5 and 10.5" 

Vintage Website
Bolt-on wheels/tires
Front, HA 17 x 8.5" with 4.25" backspacing, 245-45-17 tires
Rear:  HA 17 x 10.5" with 4" backspacing (not standard), 315-35-17 tires
Pin-drive wheels/tires
Front, HA6 17 x 8.5" with 4.0" backspacing (not standard), 245-45-17 tires
Rear:  HA6 17 x 10.5" with 4" backspacing, 315-35-17 tires
For wider 17" wheels from PS Engineering, follow the offsets below very closely.  Using 275-40 and 335-35 tires on these wheels leaves very little clearance on both the inside and outside.  Undercar exhaust using a pipe over the rear axle will not fit - you must change to a short pipe that exits in front of the rear wheel. We made changes to the splash panels behind the seats around chassis 530.  Before that chassis, we recommend 315-35 tires on the rear unless you change the inner panels.

If you are using Coleman, Sierra or Wilwood calipers, note the clearance shown below.  12.18" or 13" rotors can be used with the ERA hats.

FRONT WHEELS

The offset shown works for both bolt-on and pin drive.  For caliper clearance, see below.

Inquire for other wheel widths.

 9x17" wheel
If the back side of the wheel is machined, make sure that the drive pin hole depth of 1" minimum is maintained.  

REAR WHEEL

Increase the backspacing by 0.3" if you are using the ERA rear suspension with bolt-on wheels.

Coleman/Sierra/Wilwood caliper
The 6.85" figure shown is for 12.18" rotors.  If you are using 13" rotors, that number should be changed to 7.3".

Stock GM caliper
Uses stock 11" rotors.

HUB SPECIFICATIONS

The diagrams below show the wheel pilot dimensions and clearance necessary for front caliper clearance.  A single page diagram in PDF format is linked here.  A DXF file is available to qualified people by e-mailing me at eracars <at> gmail.com

Front bolt-on hub

Rear bolt-on hub