Reply
 
Thread Tools Display Modes
Old 12-31-2009, 12:29 PM   #1
Han
DK Sucks.
StanceWorks OG
Han's Avatar
  • Join Date: Oct 2009
  • Location: Dallas, TX
  • Posts: 4,294,967,261
  • User Status: Offline
  • Contact this user:

    Send a message via AIM to Han


Default How to Calculate Offset after Lip and/or Barrel Change

Made this a while back...


Before we start, please use Roan's (zeroluxxx) DIY Guide on measuring wheel parts so you get the correct calculation to start out with: [ http://forums.vwvortex.com/zerothread?id=3773369 ]


Maybe this could help some people as I know it can get confusing. Let's start with my wheels as an example:

Fronts:
BBS RS320
17x8 ET43 (7" barrel + .5" center + .5" lip)

Rears:
BBS RS300
17x9 ET53 (7.5" barrel + .5" center + 1" lip)

Adding the center's thickness into the equation only works if your wheels are sandwich mount (lip, face, barrel).

I moved the 1" drop lips from the rear to the front, resulting in:
17x8.5 ET37 (7" barrel + .5" center + 1" lip)

Now how did I get the final offset? Using [ http://www.1010tires.com/WheelOffsetCalculator.asp ]. I input the stock set up (8 ET43) and input the new width (8.5) and got to ET37 to maintain the same inner position because you aren't changing anything except the outer position.

I have noticed for every .5" you go out (pattern), while maintaining the same inner position/clearance, you will lower your offset by ~6mm (6.35mm to be exact (25.4 / 4 = 6.35). I have also noticed the outer position will go out 12mm (using the calculator, it gives you 12mm) (12.7 to be exact; 25.4 / 2 = 12.7)).

Then I got 1.5" lips to replace on the rears resulting in:
17x9.5 ET47 (7.5" barrel + .5" center + 1.5" lip)

Now what about if I changed the barrels up? You'd see the same pattern, but the outer position stays the same, whilst the inner position goes in or out (depending if you get smaller or larger barrels, of course).

Let's use my stock fronts for example (17x8 ET43 with a 7" barrel):

I'll put a 6.5" barrel on it, resulting in: 17x7.5 ET37 (6.5" barrel + .5" center + .5" lip). Notice the pattern again; .5" on that inner position results in 6mm lower offset (again, technically 6.35mm, easier to round down). Same thing with the inner position, it would gain 12mm (12.7 to be exact).

Well, what if I do both [smaller barrels and bigger lips]? You basically use the same formula/input the same things, but one at a time.

For example, lets use the stock fronts again but put .5" smaller barrels and a 1.5" lip on it.

Stock we know is 17x8 ET43 (7" barrel, .5" center + .5" = 8")
.5" smaller barrels we know results in 17x7.5 ET37 (6.5" + .5" + .5" = 7.5)
Now lets add that 1.5" lip to the equation: 6.5 + .5 + 1.5 = 8.5"
Final specs would be: 17x8.5 ET24 (which would gain 12mm inner clearance and outer position would "poke" 26mm more than stock lips).

Hope this helps
__________________
Quote:
Originally Posted by Jesus Christ View Post
if "life, liberty and the pursuit of happiness" doesnt include being able to buy a huge veiny motherfucker then the declaration of independence isnt worth the hemp it was written on.
Quote:
Originally Posted by Jedidiah View Post
he speaks the truth.. he doesn't even have the -- -- eyes.
  Reply With Quote
Old 05-19-2010, 05:32 PM   #2
firelizard
Banned
StanceWorks Addicted
  • Join Date: Mar 2010
  • Location: Winnipeg, MB
  • Posts: 590
  • User Status: Offline


Default

That's a lot of text to essentially say:

Lip increase, converted to MM = net reduction in offset
Barrel increase, converted to MM = net increase in offset

Lip and Barrel changes: net reduction by lip + net increase by barrel = net change in offset (could be negative or positive)
  Reply With Quote
Old 07-24-2010, 04:49 PM   #3
Ghk420
StanceWorks Newcomer
  • Join Date: Jul 2010
  • Posts: 8
  • User Status: Offline


Default

^^^^^i was thinking the same
  Reply With Quote
Old 07-27-2010, 02:28 PM   #4
migid
StanceWorks Newcomer
migid's Avatar
  • Join Date: Jul 2010
  • Location: Hungary
  • Posts: 7
  • User Status: Offline
  • Contact this user:

    Send a message via MSN to migid Send a message via Skype™ to migid


Default

Hi! I want to by an e46 m3 rim for my e36 320i. I dont know if the rim will work perfekt without the modification on the fender etc..., on the car. There isnt any e46 m3 rims near here, so i cant try it on. The rims are 8JX18 ET/IS:47 9JX18 ET/IS:26 .
  Reply With Quote
Old 08-16-2010, 09:57 PM   #5
BLKonBLK98
StanceWorks Regular
  • Join Date: Oct 2009
  • Location: Houston
  • Posts: 305
  • User Status: Offline
  • Contact this user:

    Send a message via AIM to BLKonBLK98


Default

Quote:
Originally Posted by firelizard View Post
That's a lot of text to essentially say:

Lip increase, converted to MM = net reduction in offset
Barrel increase, converted to MM = net increase in offset

Lip and Barrel changes: net reduction by lip + net increase by barrel = net change in offset (could be negative or positive)
changing the width x amount only changes the centerline x/2 which is where offset is measured from. all you ever need to know:

+1" lip = -12.7mm offset
+.5" lip = -6.35mm offset
-.5" lip = +6.35mm offset
-1" lip = +12.7mm offset

+1" barrel = +12.7mm offset
+.5" barrel = +6.35mm offset
-.5" barrel = -6.35mm offset
-1" barrel = -12.7mm offset
__________________
  Reply With Quote
Old 08-19-2010, 12:22 AM   #6
bbaction
StanceWorks Visitor
  • Join Date: Jan 2010
  • Posts: 44
  • User Status: Offline


Default

The easiest way to do this is look at a Backspace to offset chart and calculate...

Find your current width and offset then trace directly down to desired width it gives you roughly your new offset (add or subtract accordingly)
__________________
killasnapshot
  Reply With Quote
Old 02-16-2011, 08:53 PM   #7
SIN3
Foward, Down, Foward +HP
StanceWorks Regular
SIN3's Avatar
  • Join Date: Aug 2009
  • Location: So Cal___Wii Wii Land
  • Posts: 297
  • User Status: Offline
  • Contact this user:

    Send a message via AIM to SIN3


Default

saved.
__________________
2006 M3 Cabrio
2004 ZHP Cabrio

/stanceworks\
  Reply With Quote
Old 03-07-2011, 11:30 PM   #8
fastcar
StanceWorks Visitor
  • Join Date: Sep 2010
  • Location: Cal
  • Posts: 71
  • User Status: Offline


Default

Quote:
Originally Posted by firelizard View Post
That's a lot of text to essentially say:

Lip increase, converted to MM = net reduction in offset
Barrel increase, converted to MM = net increase in offset

Lip and Barrel changes: net reduction by lip + net increase by barrel = net change in offset (could be negative or positive)
I was thinking the same
  Reply With Quote
Old 07-25-2011, 02:51 AM   #9
indy510
Sawzall and
StanceWorks Addicted
indy510's Avatar
  • Join Date: Nov 2010
  • Location: Califlorina
  • Posts: 927
  • User Status: Offline


Default

.
That chart is really helpfull ....... . I am trying to figure out if I can fit a 16x8.5 -6mm wheel

I have 16x8 +12 .. . so according to that chart, if my math is right... I think I need 24mm of spacers to replicate a 16x8.5 -6mm???

.... assuming I will use the same tires is my math correct???,,,,, it's gonna be a really tight fit,, every mm counts
  Reply With Quote
Old 07-27-2011, 02:52 PM   #10
Francois Dillinger
smells of rich mahogany
StanceWorks OG
  • Join Date: Jun 2010
  • Location: California
  • Posts: 5,509
  • User Status: Offline


Default

That chart is awesome. Anything saving me from doing math gets a thumbs up in my book.
  Reply With Quote
Old 07-27-2011, 03:29 PM   #11
Ollie
StanceWorks OG
  • Join Date: May 2009
  • Location: NYC
  • Posts: 4,950
  • User Status: Offline


Default

Quote:
Originally Posted by firelizard View Post
That's a lot of text to essentially say:

Lip increase, converted to MM = net reduction in offset
Barrel increase, converted to MM = net increase in offset

Lip and Barrel changes: net reduction by lip + net increase by barrel = net change in offset (could be negative or positive)
lol ok but you're wrong. thanks anyway
__________________

IG: @_olliee
  Reply With Quote
Old 07-27-2011, 03:45 PM   #12
Noodle
StanceWorks Visitor
  • Join Date: Jul 2010
  • Posts: 31
  • User Status: Offline


Default

i was going to say easiest way is just know the backspacing . If you have a 4" backspace on a 9" wheel and you add a 1/2" wider lip then just figure the offset on a x9.5 with a 4" backspace.
  Reply With Quote
Old 10-30-2011, 03:17 AM   #13
jamesklass
Guest
  • Posts: n/a
  • User Status:


Default

I know it can get confusing. Let's start with my wheels as an example


  Reply With Quote
Old 11-07-2011, 11:36 AM   #14
Capt. Obvious
Porschenozzle
StanceWorks Regular
Capt. Obvious's Avatar
  • Join Date: Nov 2009
  • Location: Renton, WA
  • Posts: 487
  • User Status: Offline


Default

__________________
-Darrick

911 Thread
Frankenbike Build

  Reply With Quote
Old 04-18-2012, 09:56 AM   #15
scaredofstance
StanceWorks Regular
scaredofstance's Avatar
  • Join Date: Feb 2010
  • Location: Central NC
  • Posts: 495
  • User Status: Offline


Default

nice thread. i suck at math. this will help. lol
i know its old, whatever.
__________________
I haz 4 wimz. need 4 more.
  Reply With Quote
Old 12-30-2012, 01:06 AM   #16
ripNdip
StanceWorks Visitor
  • Join Date: Jun 2011
  • Location: McLean, VA
  • Posts: 111
  • User Status: Offline


Default

I have work vs-xx's that are 18x8 et34 with 1.5" lips and im putting on 2.5" lips. So will they be 18x9 et9 or et21? i keep being told different from multiple people.
Thanks
  Reply With Quote
Old 02-15-2013, 06:37 AM   #17
projektzwo
StanceWorks OG
projektzwo's Avatar
  • Join Date: May 2010
  • Location: Bulgaria / EU
  • Posts: 2,544
  • User Status: Offline


Default

there are wheels that the face can be reverse or sandwich mounted, then we can have two wheels with same lip and barrel sizes but different offset...

i think Capt. Obvious's way of measuring is the best in this case...
__________________

flickr
  Reply With Quote
Old 05-10-2013, 03:08 PM   #18
properstyle
Properstyle
StanceWorks Visitor
properstyle's Avatar
  • Join Date: Mar 2013
  • Location: Miami FL
  • Posts: 89
  • User Status: Offline


Default

I think the problem with his method is he is measuring the outer width of the barrel not bead to bead. wheels to my understanding are measured bead to bead and the offset is determined by that so If you measure from the outer rim as he has shown your adding another inch in most cases to actuall measure size of the wheel... great thread.....
__________________
" You made your choice, I made my choice, at the end of the day if you don't like my choice it's your problem not mine"

New Z build
http://www.stanceworks.com/forums/sh...37#post1320337

The M3 Build.
http://www.stanceworks.com/forums/sh...ad.php?t=46890

  Reply With Quote
Old 05-11-2013, 09:13 AM   #19
scaredofstance
StanceWorks Regular
scaredofstance's Avatar
  • Join Date: Feb 2010
  • Location: Central NC
  • Posts: 495
  • User Status: Offline


Default

I thought wheel width was bead to bead and offset was outer to outer?
__________________
I haz 4 wimz. need 4 more.
  Reply With Quote
Old 06-18-2013, 07:21 AM   #20
wrobbin
StanceWorks Newcomer
  • Join Date: Jun 2013
  • Location: Box 337, Brockport, New York 14420, USA.
  • Posts: 10
  • User Status: Offline


Default

Great info! I wonder if this is the same for all wheels, or just BBS? It would make sense to have an understood way of measuring, but you never know.
  Reply With Quote
Old 09-16-2013, 09:54 AM   #21
a112
13"
StanceWorks Regular
a112's Avatar
  • Join Date: Jan 2011
  • Location: Lipik, Croatia
  • Posts: 304
  • User Status: Offline
  • Contact this user:

    Send a message via MSN to a112


Default

http://stu.taylor-net.co.uk/tools/offset
  Reply With Quote
Old 09-27-2013, 10:41 PM   #22
jenyanderson
StanceWorks Newcomer
  • Join Date: Sep 2013
  • Posts: 2
  • User Status: Offline


Default

wow... this is good thread. just anyone know about Honda CB4 spect1 model. i just want to know what it's having common errors.
__________________
codesys
  Reply With Quote
Old 01-23-2014, 04:47 AM   #23
daniel_lucian
scared of heights
StanceWorks Addicted
daniel_lucian's Avatar
  • Join Date: Nov 2010
  • Location: Bucharest, Romania
  • Posts: 772
  • User Status: Offline


Default

Hi guys,

I have a little dilemma and I hope some of you ran into this so you can give me some piece of advice. I read the whole thread but I'm still confused.

I have a set of OZ Futura 18x8J, ET 35, 1.5'' lip that I run with 24mm adapters and 205/40/18 tires.



I now want to change the lips with new ones measuring 2.75'' to make the wheels 9.25'' wide and put 215/40/18 tires on them. Will that change the offset of the rim? Since the width of the rim will increase, I plan to mill down the adapters a few mm to a smaller size until it gets to the fitment I want (probably similar to above). Do you guys think it will work?

P.S: I would prefer not to do any fender work. I like them the way they are
__________________

Last edited by daniel_lucian; 01-23-2014 at 04:49 AM.
  Reply With Quote
Old 03-04-2014, 02:46 AM   #24
sponcar
StanceWorks Newcomer
  • Join Date: Jan 2014
  • Posts: 3
  • User Status: Offline


Default

Quote:
Originally Posted by daniel_lucian View Post
Hi guys,

I have a little dilemma and I hope some of you ran into this so you can give me some piece of advice. I read the whole thread but I'm still confused.

I have a set of OZ Futura 18x8J, ET 35, 1.5'' lip that I run with 24mm adapters and 205/40/18 tires.



I now want to change the lips with new ones measuring 2.75'' to make the wheels 9.25'' wide and put 215/40/18 tires on them. Will that change the offset of the rim? Since the width of the rim will increase, I plan to mill down the adapters a few mm to a smaller size until it gets to the fitment I want (probably similar to above). Do you guys think it will work?

P.S: I would prefer not to do any fender work. I like them the way they are
Based to what I understand, your offset will be lower (something around et8 ) therefore you will be poking. The only way you can get it done and be able to run it in your car is redrilling your wheels and ditch the adapters. (someone correct me if im wrong).
  Reply With Quote
Old 04-08-2014, 11:08 PM   #25
supastardavid
StanceWorks Newcomer
  • Join Date: Apr 2014
  • Posts: 1
  • User Status: Offline


Default help

Reading this made me more confused. I have a set of BBS RS. 17x8 +19 and 17x9 +0. What size lips would I need to make it 17x9.5 all around?
  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 10:45 PM.