Wheel Back--Space Info Needed

[70rcode]

Hey all,....need some help on Chrysler/Mopar Oem type Steel wheel Back--Space measurement procedure.....Have repeatedly ordered Wheel Vintiques thru Summit, Chrysler Oem 15 x 8 x 4.5 lug spacing x 4.0 Back-Spacing and receiving 4.5" Back--Spaced wheels when i measure them.... What am I doing wrong before I go the Custom built, Non-refundable route & same problem occurs ?

 

[33 IMP]

Are you ordering, BY PHONE, and telling them not to ship the wrong wheels, just cause they have them in stock? Frankly, I didn't know a 4"bs was even available till I looked at summits site.
A 4.5 bs usually fits better. Any particular reason you want 4"?
Are you ordering the 63-581204 ?

 

[70rcode]

Hi 33,....Yes,.... 63--581204, verbally by phone & Emphasizing the importance of the 4.0" Back-Spacing & no substitute (plenty in stock)...The Hoosier Quick Time 29 x 11.5--15 fit & clear the Leaf springs better with the 4.0 Back-Spacing...

 

[70rcode]

Could I be measuring the BS wrong ?

 

[66Satellite47]

Back spacing is measured from inside the lip not from the outer lip. And even so, the spacing can be tricky.

 

[70rcode]

Hi 66Sat,... That's the problem I've talked directly to 4 Summit customer service agents, Wheel Vintiques, Wheel Smith, Jegs & Stockton Wheel & everyone says with wheel front side Down, "Lay straight edge across backside wheel Lip Edge & measure to hub face" ...& That measurement comes up 1/2" Longer than your Inside Lip method..... They're all telling me 4.5" BS wheels have been put in 4.0" labeled shipping boxes !!

 

[66Satellite47]

Hi 66Sat,... That's the problem I've talked directly to 4 Summit customer service agents, Wheel Vintiques, Wheel Smith, Jegs & Stockton Wheel & everyone says with wheel front side Down, "Lay straight edge across backside wheel Lip Edge & measure to hub face" ...& That measurement comes up 1/2" Longer than your Inside Lip method..... They're all telling me 4.5" BS wheels have been put in 4.0" labeled shipping boxes !!

I think the BS is measured from the inside of the lip because the lip varies, from wheel to wheel. if Summit et all thinks otherwise I can't explain. Maybe uninformed.

 

[Darter6]

Could be China doesn't know what inches are...

 

[33 IMP]

I think the BS is measured from the inside of the lip because the lip varies, from wheel to wheel. if Summit et all thinks otherwise I can't explain. Maybe uninformed.

I would have to disagree. I have always measured backspace from the wheel edge to the mounting face. If you look at an aluminum wheel, 15x8, meaning an ACTUAL nine inches wide (width is measured bead to bead) , if the bs is 4.5, the offset will be zero, meaning the mount face is in the middle. That is the way summit, and everybody else will list that wheel.
Measuring the way I do, I get the same results the wheel maker states. The way you do it would be off by the thickness of the bead.

 

[33 IMP]

70Rcode, if they are all in the wrong boxes, AND THEY KNOW IT, have someone check the wheels before they ship them.....

Oh, wait. THATS not gonna happen......

 

[66Satellite47]

I would have to disagree. I have always measured backspace from the wheel edge to the mounting face. If you look at an aluminum wheel, 15x8, meaning an ACTUAL nine inches wide (width is measured bead to bead) , if the bs is 4.5, the offset will be zero, meaning the mount face is in the middle. That is the way summit, and everybody else will list that wheel.
Measuring the way I do, I get the same results the wheel maker states. The way you do it would be off by the thickness of the bead.

OK

 

[Darter6]

measured backspace from the wheel edge to the mounting face.

That's they way I was told. Test against a known wheel backspace to see.

 

[70rcode]

I'm confused now,.....How do I measure my 15 x 8" wheel's Offset then ?

 

[33 IMP]

I'm confused now,.....How do I measure my 15 x 8" wheel's Offset then ?

You can't MEASURE offset, that's why I don't like it, it has to be calculated from measurements you can make, namely backspace (unless of course you are looking in a catalog that lists wheels by offset, then you have to calculate the backspace.)
I don't bother with offset, cause I can't remember which direction is + and which is - and I don't care. Tell me what the bs is and I'll know where the wheel is.

 

[33 IMP]

Okay, anyway. For your example, a 15x8 steel wheel with 4" backspace, I'm gonna assume an overall width of 8.5" (8" between beads, plus a quarter inch steel bead on each side) . So, a zero offset would be 4.25 backspace. Yours is a 1/4" different, so a quarter of 25.4 mm, your offset would be 6mm and change. Plus or minus, I have no idea. I could find out. So can you.

 

[Darter6]

Just a description.Let's say a 8'' wheel using zero as the center line, meaning 4'' to front of center 4'' to rear of center.
Positive offset would be 3'' to front of center and 5'' to rear of center (front wheel drive and some late models)
Negative offset would be 5'' to front of center and 3'' to rear of center.
That's the best that I can describe offset.

 

[33 IMP]

So negative is "deep dish", and positive is hiding most of the tire in under the car? I have a pair of wheels with each of those extremes.
If somebody told me what those offsets were, in mm, I still wouldn't have a good idea of what they look like.
If I told you I have a 15x10 1/2 with 7 1/4 bs, and a 15x12 with 3 1/2 bs, I bet you can tell which is which.

 

[70rcode]

Summit specs this wheel Backspacing = 8.0" & Offset = -12.00 mm. My direct measurements get BS = 4.5" & Offset = 0.0mm . I need help to verify I'm measuring these correctly.. Each should be separately Measurable & agree. Thx.

 

[33 IMP]

I think summits offset # would be right if that 15x8 wheel was aluminum, and actually 15x9 overall. I don't think a STEEL 15x8 is 9" wide, and I stand by my numbers in post #15.

 

[70rcode]

Both Summit & Wheel Ventiques (the manufacturer) spec this steel wheel as posted.....The Ventiques sales assistant sounded very competently knowledgeable about this wheel..