Rear wheel backspacing questions

[dickeymoore]

I have a 1979 Chevy Malibu with a 8.5 Grand National Rear End in the back all stock I was wondering what is the correct or a good backspacing for Wheels I'm trying to buy 17 x 8 on the rears I see they have4", 4.5" and 4.81" backspacing will the 4.81 inch backspacing be good enough I don't want them to stick out too far from the fender Wells

 

[oldsofb]

The factory 15x7 Olds SSIII came with a 4 inch backspace. A lot of repo's that would come in 15x8 would have the 4.5 backspace. That seems a standard backspace for an 8 inch rim regardless of 15, 16, 17 inch size.

The best way is to measure the actual vehicle and find the limits of what will fit. They make wheel checking devices to help get that right.

Maybe you have a buddy with 17's that you could try on your car and see what works.

Hutch

 

[dickeymoore]

Ok

 

[lilbowtie]

Figure it out mathematically - You have aprox 5.5 inches from the face of drum to the frame. You need to know what tire you are going to run and get the cross section of that tire. Lets say it is 10 inches, that means the tire is going to be 2 inches wider than the rim or 1 inch per side. So if you run a 4 inch backspace plus and extra inch for the tire it will fit (5 inches). A 4.5 backspace w/ an inch for the tire you will hit the frame (5.5 inches) So find out which tire you are going to use, get the cross section and go from there. Measure both sides to make sure it's centered and the drum to frame measurment is good. You can also measure out to see if they stick out of the wells

 

[dickeymoore]

275 40 17 rear tires with 10.83 width so 4" backspace will work?