15x10 wheels with 3.50” BS do they fit

[Zman91]

Hello everyone I’ve spent about a hour looking around and can’t find a concrete answer. I don’t fully understand the whole back spacing and offset thing

I’m looking at a set of wheels 15x8 with 4” bs I’m fairly confident these will fit with 215/70/15 tires

The rear are 15x10 with 3.5” bs and this I’m unsure of, it seems most guys are running a 4.5” bs with 15x10. The truck is lowered on djm beams and rear hangers I want to run a 275/60/15 on the rear but having trouble finding a wheel I like with a 4.5 bs

Any help would be extremely appreciated

[pcmdub]

Yeah...it is tough and there are tons of variables with old trucks...

Backspace is just the distance from the wheel bolting surface to the back of the rim. Wheel offset is a similar concept that uses mm of + or - movement from a center.
https://www.tyresizecalculator.com/wheels/wheel-offset

The 15x8 fronts will fit with 3" to 4" of backspace with DJM and factory brakes. 235 or 255 tires will fit better on an 8" rim thou.

The rear needs more info before someone can help you out. Different rear end, springs, brakes, etc can change the wheel fitment.

Actually, you can just measure your own truck here. Leave the truck on a flat surface, wheels on, (set the brakes and chock the tires), the get underneath and measure the distance from the outside brake drum, to the inside fender. Should be around 4-5" Then sitting on the side of the wheel, measure from the same spot on the inside of the fender to the outside fender lip. Subtract the two and you can see where you sit. Most F100's have shorter wheel tracks and can go with a smaller backspace (deeper faced wheel from the outside). Some just use a spacer to push them out a bit.

[390FE1972]

Here is some additional information on backspace and offset:

https://www.fordification.com/forum/vie ... =5&t=59040
https://www.fordification.com/forum/vie ... =5&t=64122

Regards

[Zman91]

Thanks guys. I’ll have to get under there this weekend if I have some and do some measuring

And for record my Truck has a 9” Rear end,