Will this work on my 1979 Cutlass Calais? 10 inch wide rear with 4.5 backspacing?

[JAMCAR223]

Just so I understand, and this is just for my knowledge........if I have a wheel with say the 4.5 backspacing......to get it away from the frame I'd need
a spacer of say 1.25 is that correct??? Would that then make the backspacing 3.25? Im just trying to understand this........

Yes

 

[azmusclecar]

Yes

Thanks for the reply...........I think I finally get it............to put a 10 inch wheel on my Cutlass I would need 5.5 at minimum backspacing
to keep it away from the frame.........and yes the tire bulge does add another half inch. So a wheel with 5.75 to 6 inch backspacing would be needed.
Between all these metric +19 or -9 why can't we all just get along with one measurement............Thanks again. AZ

 

[565bbchevy]

Thanks for the reply...........I think I finally get it............to put a 10 inch wheel on my Cutlass I would need 5.5 at minimum backspacing
to keep it away from the frame.........and yes the tire bulge does add another half inch. So a wheel with 5.75 to 6 inch backspacing would be needed.

The higher the number for backspacing the closer it gets to the frame a 5.5" BS would probably have the rim itself rubbing on the frame.
Section width or "tire bulge" can vary and be 1-2" or more overall wider than the rim.

 

[565bbchevy]

Nowadays most wheels are sold by using the offset to show how it fits.
Example a 15 x 8 rim that the mounting point is centered will have 0 offset but will have 4.5" of backspace because it includes the 1/2" thickness of the rim.

 

[azmusclecar]

The higher the number for backspacing the closer it gets to the frame a 5.5" BS would probably have the rim itself rubbing on the frame.
Section width or "tire bulge" can vary and be 1-2" or more overall wider than the rim.

Yes I got it backwards.............the backspacing needs to be LESS to push it away from the frame? YES? So a 10 inch wheel would need to have a
backspacing of say.........3.50 instead of 4.50???
I'm just trying to get these numbers going in the right direction........I can see why math was my least favored subject in school...

 

[azmusclecar]

Nowadays most wheels are sold by using the offset to show how it fits.
Example a 15 x 8 rim that the mounting point is centered will have 0 offset but will have 4.5" of backspace because it includes the 1/2" thickness of the rim.

View attachment 122874

So actually a 10 inch wheel is basically a 9 inch mountable surface wheel due to the 1/2 inch edge.........Do I at least have this right?

I have no idea why this is so hard for me to grasp..............maybe Ol' Skool is catching up to me, thanks for your patience........

I need to start opening the doors to the garage when I have the car running I'd say huh?????????😊

 

[565bbchevy]

Wheel width is measured the same way regardless if you have a wheel with offset or backspace.

 

[565bbchevy]

A 10" wheel is typically going to either have issues with the tire rubbing on the frame or sticking out of the wheelwell (not a good look IMO)

 

[88ss408]

I have a 255 right now on a 3.75 inch back spacing 15x7 wheel.
I also had 295 on a 15x10 can't remember the backspace on it would have to measure.
But there was no rubbing and I don't have my frame moded.