front wheel - backspacing

[MYBAD79]

Stock rim has 4" BS. Is anyone running 4 1/2" or 5" BS on the front ?? I am wondering if there is another 1/2" or so room to run 4 1/2" BS.

The sketch below shows a stock rim (8" nominal width is 9" overall), nominal width is measured where the tire seats inside the rim's lip.

It seems that a 9.5x17 rim with 4" BS moves the outboard side of the rim out by 1 1/2" compared to stock. I have barely room for that and a 4 1/2 BS rim would fit better, just not sure if it would hit the frame or swaybar on the inboard side.

 

[mrvette]

I can't say who read what where or what research....but...

I have had 17x9.5 C4 wheels on all 4 corners of my '72 for some almost 16 years now...using VBP 2.5 inch wheel adaptors....

I was lazy in my measurements....so measured off the outer FACE, (not the turnout) on the rim surface....to the inner face of the mounting....

this all done well before the internet and all this superior information....

the same standard of measure was done with straight metal cut to length to set on the FACE of the outer flange the tire bead set on...like the upper section of your drawing SEEMS to show...eliminating that little lip turn out...so my olde tyme notes are to that time period....sorry to be so confusing...

so by MY measures the stock 15x8 offset was 3.5 inches

the C4 wheels measured 7" even....

so with 2.5 inch adaptor yielded 4.5 net and so I cut off the emergency brake cable mount and moved to behind the rotor....moved the frame mount end outboard and angled it into position...

so that gave me 3/4 inch of savings in tire clearance...

and I ate up about 50% of the factory clearance ....

so kept the same centerline of the tire/wheel combo....

did the same in front....but one size smaller in tires...

275/50/17 rear......255/50/17 front....

:mobeer:

 

[MYBAD79]

ordered the rims with 4" BS... should fit.....

rota rotundus.....

:drink::drink: