: Backspacing for 8" wide rims on '84 Sedan Deville

05-31-05, 07:03 AM
I'm looking at this fender, and thinking I could even go bigger than 8x15, but anyways, what's the backspace number I'm looking for?

Thanks for your help,

05-31-05, 04:45 PM
I don't know how well this relates, but the 17" Impala wheels are:

17 X 8.5, 5 X 5 Bolt Pattern, 4.95" Offset, J or JJ Flange

Found at:

My guess is the 15x8's are 4.5" backspacing. I will email a friend and see what he says to confirm. Look for my edit of this post.

05-31-05, 05:23 PM

what's that J or JJ mean anyway?????

05-31-05, 07:43 PM
Honestly I don't know. That is what is posted there. If I find out I will let you know.

06-01-05, 11:43 AM
>Scott, do you know the wheel backspacing for the 15x8's for the
Impala/9C1? I suspect it is 4.5", that was GM's favorite for RWD for a great many cars.

There were no factory 15x8 wheels used on the B-car. However '91 and earlier C-truck (2WD truck) 15x8s will work. They look like the 15x7 9C1 wheels except for rectangular rather than round slots, and accept the same bolt-on center caps. I think the 15x7 9C1 wheels are 4.375" backspacing, while the 15x8 2WD truck wheels were 4.25" backspacing.

These same basic wheels are available from Wheel Vintiques in a 15x8 version with 4" backspacing under [42 SERIES O.E. STYLE PICK-UP RALLYE
(`71-'87) (SILVER)] p/n 42-580504. You can see this in their catalog at <http://www.wheelvintiques.com>. It is normally silver but also available in bare steel for $5 less.

><http://www.9c1.com/technical/ <http://www.9c1.com/technical/> here
shows the 17" wheels to be 4.95" backspacing, and the Impala wheels are wider, so it seems to line up. This is in reference to a question on CadillacForums.com about wheels for a 84 Deville (RWD). Thanks! Tom

The stock 17x9.5 Impala SS wheels have a 5" backspacing I believe. Scott.

06-01-05, 04:11 PM
:bouncy::dance:N0DIH IS DA MAN:dance:HELL YEAH:bouncy:

:greendudeYea MUTHA F'ER, N0DIH IS DA MAN...

Thanks for taking the time to find that out, as I'm sure many, many Cadi owners were wondering the same thing. I owe you one.


06-01-05, 11:24 PM
Keep lurking around the Scott Mueller tech pages on the Herd and other Impala SS/9C1 sites. He is THE Guru, not I. I just don't forget a number! aaaaaahhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!!

With all this talk of 8in wheels one must wonder if one is going to get the Deville to G-Machine status?

I am going to pickup a 1.5" HA rear bar for my 94 FWB in a couple weeks and then look into putting my Rancho GTIII front sway bar on the front (1.25", adjustable lever) off of my 80 Turbo Trans AM. Sorry, Rancho doesn't make 2nd Gen F car stuff and 77-96 B/D stuff anymore.... :( So the 8" wheels I am pickup up this week will get stuffed with some large meats for autocrossing!