Final Answer - Track width difference when converting front to disks

[SABLT194]

So, After researching this a bit I found about 5 different answers on how much of a change going to Dr Diffs 10.95 would make on my drum equipped 1971 Dart Swinger. I've seen everything from no change, up to 1-1/8" . To put this to bed once and for all I measured. I set each assembly up on my mill table and used a height pointer to the CL of the lower ball joint zerk fitting. The final answer is …. the disk conversion shifts the wheel mounting surface out by 23/32" or .656 on each side. Pics on my setup below.
Hope this helps someone out.
Regards,
Steve

 

[66fs]

The difference in wheel offset is +.125 approximately. So you can subtract that from your measurements.

 

[SABLT194]

The difference in wheel offset is +.125 approximately. So you can subtract that from your measurements.

I wanted to ignore the whole wheel offset thing, but thanks. Are you saying that 73 and up BBP stock rims were +.125 offset over the pre 73 SBP rims???

 

[crackedback]

Yes, the BBP wheels had more backspace

Maybe stick with approximately 5/8" to make it easy!

Nice on the measurement.

 

[SABLT194]

Yes, the BBP wheels had more backspace

Maybe stick with approximately 5/8" to make it easy!

Nice on the measurement.

Would you happen to know the width and backspace of a 1973 BBP stock A Body rallye wheel?

 

[66fs]

I wanted to ignore the whole wheel offset thing, but thanks. Are you saying that 73 and up BBP stock rims were +.125 offset over the pre 73 SBP rims???

My original 14 x 5.5, 4.50 BC Ralleyes are long gone. I measured what I had and measured the offset from center. Hub surface to inside tire bead. Both factory Ralleye rims. 15 x 6.5, 5 x 4.50 BC offset toward outside .500 inches. 14 x 5.5, 5 x 4.00 BC offset toward outside .375 inches. I did not measure as precisely as you, but I was being careful since I was ordering custom wheels for the 66 Formula S.