89 GMC Sierra EXT 1500 4wd extended cab longbed.

Also is what does a 33 translate to 275?

 

well?

 

Don't know, but you might get more help in the Chevy Silverado forum.

 

285/75s are almost 33s... and yeah z71s will fit them

 

I'm kinda new here, but Im just gonna jump right in. the first number in tire size is tread width in mm thus 275 is 27.5 centimeters and the second number is sidewall percentage so 275/75is approx 8 inches of sidewall then you add in the wheel size so a 285/75 31x11 on a 15 inch wheel or 33x11 on a 17 inch wheel anyhow hope this helps