Backspacing to Offset Conversion?
Originally Posted by slayer6x6
Lets say were looking at a 19x10 wheel with 6.25" backspacing. How do I determine the offset? Will this fit a 4th gen?
1 inch=25.4mm
10/2=5
5X25.4=127mm
THEN
You take the backspacing measurement and convert THAT into millimeters, and subtract half the wheel width from it, so:
6.25X25.4=158.75mm
158.75mm-127mm=31.75mm
Rounding the .75 up, you're left with a 32mm offset. It'll fit, but it'll be right there on the ragged edge between being out to far and being "just right." See if you can find some pics of a car with 17X11 ZR1's with a 38mm offset. That'll be pretty close to how it'll look.
Originally Posted by Chris@DTD
thesound,
You forgot to add the 1/2" per side for the rim flange. The wheel is physically 11 inches wide.
158.75-139.7 = 19.05mm offset
You forgot to add the 1/2" per side for the rim flange. The wheel is physically 11 inches wide.
158.75-139.7 = 19.05mm offset
Originally Posted by thesoundandthefury
Wrong. Advertised widths are advertised widths. Not all rims have a "flange." All that is is a design style. Regardless of whether a company chooses to incorporate a flange in their wheel design, what they advertise the width as is the TOTAL width.
Now the "flange" is a varying dimension, 1/2" is a safe amount.
So . . A 9" wide wheel could have an "actual width" from lip face to lip face about 10" wide . .
Therefore, backspacing and offset are related, but "technically" it is not an exact science of figuring one from another, but you can get close. The one factor one MUST know to translate between them is the exact dimension of the bead flange.
Last edited by Xsta Z 28; Feb 28, 2006 at 11:16 AM.
Originally Posted by Xsta Z 28
Sorry sir . . . YOU are incorrect . . . "Advertised" width of a wheel is the distance BETWEEN the bead flanges . . . always has been and always will be.
Now the "flange" is a varying dimension, 1/2" is a safe amount.
So . . A 9" wide wheel could have an "actual width" from lip face to lip face about 10" wide . .
Therefore, backspacing and offset are related, but "technically" it is not an exact science of figuring one from another, but you can get close. The one factor one MUST know to translate between them is the exact dimension of the bead flange.
Now the "flange" is a varying dimension, 1/2" is a safe amount.
So . . A 9" wide wheel could have an "actual width" from lip face to lip face about 10" wide . .
Therefore, backspacing and offset are related, but "technically" it is not an exact science of figuring one from another, but you can get close. The one factor one MUST know to translate between them is the exact dimension of the bead flange.
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Originally Posted by thesoundandthefury
Okay I'll buy the "bead flange" explanation, but the part I'm not buying is the 1/2 inch on each side bit.
I just went and measured the bead flanges on the HPR5's I have and one side measures 1/4 and the other side measures 2 inches. With this much variation on just THIS wheel,
I don't even wanna contemplate how hard it would be to choose a set of wheels that would fit any specific vehicle if this was the standard by which the wheel width was measured.
There could be a million and one combinations for bead flange widths depending on how the wheel was designed.
IMHO, measuring TOTAL width is still "safer."
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Originally Posted by Xsta Z 28
Not sure how you can have a "flange" of 2". The "flange" is the small "flap" on either side of the wheel that the tire bead is pressed against. But a wheel can have a thicker flange on the inside and outside. Take for example a FIKSE 3 peice wheel, where the outside "hoop" is a rolled piece of aluminum, where the inside hoop is cast aluminum so the flange widths/thicknesses do vary.
(Officially taking foot out of mouth.) My apologies to Chris@DTD and Slayer6X6 for my errors in judgment. And thanks Xsta for the new knowledge.
Originally Posted by thesoundandthefury
. . . . And thanks Xsta for the new knowledge.
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http://cgi.ebay.com/ebaymotors/ws/eB...Pr3_PcY_BID_IT
Well this is why I was asking. Somebodys gonna get a good deal on these, I dont think Im gonna bid though.
Well this is why I was asking. Somebodys gonna get a good deal on these, I dont think Im gonna bid though.
