I have my factory jeep rims with 31x10.5015 an they rub my lca's so I bought spacers well I'm having a shimmy problem with them on the front so I brought them to work an there true so now I'm going to put breaks on the front but the question is is it.gonna hurt to just rub two on the back? Its 4x4 an there 1.75" thick

 

I would just buy some new wheels and forget about running spacers. You can find some nice wheels for cheap at www.summitracing.com and not have to worry about a wheel flying off because of a failed spacer.

 

Quality spacers properly installed are perfectly safe.

Quality spacers properly installed will not cause any alignment/steering/wobble issues.