Do yourself a favor and lose the factory "pebble gatherer" wheels and put aftermarket wheels on. Spacers are just a failure waiting to happen, IMHO. Actual wheels are a lot stronger since they mount up solid to the hubs, and with factory length studs too.

I used to get a screeching rock in a brake pad about every time I wheeled, but not since swapping wheels. The new ones don't collect ice and snow either.