How do you figure out offset rims ?

[bigcowl-imp]

A guy is selling some rims that he says will fit a fox Mustang but i'm coming up with something that won't fit... so i'm doing something wrong.... can you explain ?

This is what he listed...

-17x10 Rears 5-100/5-114.3 (5 x 4.5") Bolt Patterns [+20mm Offset]
-17x8 Fronts 5-100/5-114.3 (5 x 4.5") Bolt Patterns [+25mm Offset]

[License2Bill]

Offset is the distance from the mounting surface of the wheel to the centerline of the wheel. If the offset is negative, the wheel will have a concave or dished appearance. If it is positive, the wheel will have a flatter appearance, like the stock Marauder wheels.

http://www.discounttiredirect.com/images/wheel.offset.gif

bF4s5wDdvBg

[fastblackmerc]

Offset is the distance from the mounting surface of the wheel to the centerline of the wheel. If the offset is negative, the wheel will have a concave or dished appearance. If it is positive, the wheel will have a flatter appearance, like the stock Marauder wheels.

http://www.discounttiredirect.com/images/wheel.offset.gif

bF4s5wDdvBg

Good explanation!

[Embassy]

When I was considering aftermarket wheels for the MM, I used this helpful site:

http://www.1010tires.com/Tools/Wheel-Offset-Calculator (http://www.1010tires.com/Tools/Wheel-Offset-Calculator)

[ChiTownMaraud3r]

20mm will stick out of the fender way too much.

[ChiTownMaraud3r]

When I was considering aftermarket wheels for the MM, I used this helpful site:

http://www.1010tires.com/Tools/Wheel-Offset-Calculator (http://www.1010tires.com/Tools/Wheel-Offset-Calculator)


i like this one personally.

http://www.rimsntires.com/specspro.jsp

[MOTOWN]

Offset is the distance from the mounting surface of the wheel to the centerline of the wheel. If the offset is negative, the wheel will have a concave or dished appearance. If it is positive, the wheel will have a flatter appearance, like the stock Marauder wheels.

http://www.discounttiredirect.com/images/wheel.offset.gif

bF4s5wDdvBg

This should be a "STICKY" excellent post bud! and spot on!:bows:

[massacre]

http://www.jegs.com/p/Percys/Percys-WheelRite-Wheel-Fitment-Tool/761153/10002/-1

[bigcowl-imp]

20mm will stick out of the fender way too much.

Thats what i was thinking....at least on the backs..

So i'm i doing this right ?

-17x10 Rears [+20mm Offset = .7874 + 5.000 = 5.7874. offset right ?

-17x8 Fronts [+25mm Offset = .9842 + 4.000 = 4.9842 offset right ?

[License2Bill]

What you are trying to describe is backspacing. That is the distance from the mounting surface to the inside "face" of the wheel/bead.

[bigcowl-imp]

yes i know this but are my numbers right ?

[bigcowl-imp]

This link worked but i don't understand how they come up with .500 more then i do ??

http://www.ccwheel.com/technical-converter.php

I come up with

17x10 Rears [+20mm Offset or back spacing = .7874 + 5.000 = 5.7874. offset or back spacing

17x8 Fronts [+25mm Offset or back spacing = .9842 + 4.000 = 4.9842 offset or back spacing


They come up with

17x10 Rears [+20mm Offset = .......................6.2874

17x8 Fronts [+25mm Offset =......................... 5.4843

I'm taking half the rim plus the 20mm

[bigcowl-imp]

20mm x .03937 = .7874

25mm x .03937 = .9842

[ChiTownMaraud3r]

I too have tried the math and always seems to come up with different numbers than what the online calculators give. I think the best thing would be to look for someone with a crown vic '03+ that has the same wheel specs you are looking for to confirm how they will visually look/fit.

[Jeffonebuck]

[QUOTE] My 8" wheel marauder wheel is 9" outside to outside, so if you try doing the math yourself you will have to use 9" instead of 8" in your calculation. Also your tire will be wider than the overall rim width

http://www.discounttiredirect.com/images/wheel.offset.gif





Sent from my iPad using Tapatalk

[ChiTownMaraud3r]

[QUOTE] My 8" wheel marauder wheel is 9" outside to outside, so if you try doing the math yourself you will have to use 9" instead of 8" in your calculation. Also your tire will be wider than the overall rim width

http://www.discounttiredirect.com/images/wheel.offset.gif





Sent from my iPad using Tapatalk


Didn't know this, always used 8" thanks.

[License2Bill]

This should be a "STICKY" excellent post bud! and spot on!:bows:
Thanks man. Means a lot coming from you!

[EMAS]

Thats what i was thinking....at least on the backs..

So i'm i doing this right ?

-17x10 Rears [+20mm Offset = .7874 + 5.000 = 5.7874. offset right ?

-17x8 Fronts [+25mm Offset = .9842 + 4.000 = 4.9842 offset right ?

Nope, the offset is the offset from the center line as described above. It sounds like what you want is the back spacing. To estimate the back spacing when you know the offset, you take the advertised width add 1" and then divide that by 2. Then add the offset to that number.

The reason you add the 1" to the advertized width is because the advertized width is measured where the bead of the tire sits inside the "lip" while back spacing is measured from the outside of the lip. In general the outside to outside width is ~1" more than the advertized width. Yes it does vary depending on the wheel construction.

[bigcowl-imp]

Nope, the offset is the offset from the center line as described above. It sounds like what you want is the back spacing. To estimate the back spacing when you know the offset, you take the advertised width add 1" and then divide that by 2. Then add the offset to that number.

The reason you add the 1" to the advertized width is because the advertized width is measured where the bead of the tire sits inside the "lip" while back spacing is measured from the outside of the lip. In general the outside to outside width is ~1" more than the advertized width. Yes it does vary depending on the wheel construction.

This is what i was looking for ...thank you vary much.

[SGT_MERC]

I use this site. It lets me compare 2 completely wheel/tire combinations and explains the differences between the two.
Wheel and tire size calculator (http://www.rimsntires.com/specspro.jsp)