I got a 99 gmc sierra 2wd and i just ordered these http://www.summitracing.com/parts/AEW-3302-0962/ wheels today and i see there was two different backspacing I am not to smart with the backspacing thing yet can somone tell me PLEASE!! that these are gona fit my truck and im not gona have to send em back

 

Since they are 20s they will fit. if they were like 16s that would be too much backspacing. i think 6 is the most you want with smaller rims.

 

Ok good.. Now i had these same wheels on and s-10 and had to run spacers in the front am i gona have to run spacers on my sierra? anybody have these wheels on there trucks thanks!!

 

Everyone has those wheels, they're very popular. I think factory 20" backspacing is 5.9, so you shouldn't have to run spacers.