Tire and wheel size/from 17" to 20" OEM

[cginstructor]

Fellas and ladies,

Currently, I have 285/70-17 w/ 2 " leveling kit with no rubbing. I recently bought four 20" oem GMC rims and I want a compatible size.

I looked in the "stickies" and found some good information. However, I wasn't able to find answers to the following..

Stock 17" backspace ?
Stock 20" backspace ?

Also, I was considering 285/55-20 . According to the charts posted, there seems to be no rubbing issues with 285/55-20 set up but, others have said there will be. However, the 285/70-17 and 285/55-20 are almost the same size.

Given the backspace on the 20" could I also go to a 305?


Any cares, comment, and concerns are welcome

r/,

John

[adampaul1964]

Backspace depends on offset, offset being the distance the mounting surface is from the centerline of the rim,factory offset is 31mm and 305/50/20 fit without modifcation. See my truck.