I use wheel spacers on My +8 Bitsa with disk wheels. When I converted to Wilwood brakes and rotor the caliper interfered with the wheel. The amount of thread loss on the studs are a concern. But I really do not know how many threads are too few. However I am careful to use a torque wrench to insure they are set properly.
"I think I've read the PCD is 4x130 - does that sound right?" Do not know what "PCD" is. I can guess it is 4 studs X 130mm long.
