cwapface

My 87 pickup SR5 had the factory 15x7 aluminum alloy wheels on it, with a machined finish that was corroding and looked like crap. I found a set on craigslist with tires for cheap, but they appear to be OEM silver painted or coated. The lug holes are smaller and tapered, and thanks to this forum I went out and got some acorn lugnuts to mount them.

Now I'm curious, the wheels I bought must be steel, correct? How many different versions of the split 4-spoke wheels are there? Are they limited to SR5 models? Are my old alloy rims worth anything besides scrap value?