Notices
997 Forum 2005-2012
Sponsored by:
Sponsored by:

Help on offset calculations for new wheels

Thread Tools
 
Search this Thread
 
Old 07-31-2009, 12:32 PM
  #1  
Porsche Eye
2nd Gear
Thread Starter
 
Porsche Eye's Avatar
 
Join Date: Jul 2009
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default Help on offset calculations for new wheels

Just got a brand new 997-2 S Artic Silver 6 spd.

The car currently has the OEM S wheels:
8X19 offset 57 and 5 mm spacer
11x19 offset 67 and 5 mm spacer

Looking to buy Victor Zehn wheels of
8X18 offset 45
11x18 offset 55

Questions:
1-Will the new wheels move inside or out ?
2-Will the new wheels rub on fender or suspension ?
3-Do you recommend this ?
4-Do I substract or add the spacer to the wheel in order to calcualte OEM offset ?


Thanks a lot!!!
Old 07-31-2009, 12:54 PM
  #2  
jhbrennan
Rennlist Member
 
jhbrennan's Avatar
 
Join Date: Mar 2006
Location: Austin
Posts: 6,571
Received 81 Likes on 73 Posts
Default

Spacers move wheels out reducing offset - so 5mm spacer on 67mm wheel gives an effective offset of 62mm. You can go here and plug in your options and see what happens - http://1010tires.com/WheelOffsetCalculator.asp
Old 07-31-2009, 01:56 PM
  #3  
GreggT
Addict
Rennlist Member

 
GreggT's Avatar
 
Join Date: Nov 2001
Location: Madison, WI
Posts: 1,842
Received 50 Likes on 36 Posts
Default

Victor who?
Old 07-31-2009, 02:31 PM
  #4  
kdurg
Addict
Rennlist Member
 
kdurg's Avatar
 
Join Date: May 2003
Location: Virginia
Posts: 1,695
Likes: 0
Received 5 Likes on 5 Posts
Default

Not a bad looking rim. You sure you want to drop down to 18inch config though ? ET55 will be close to outboard of your fender line in the rear. Definitely no need for spacers.
Attached Images  
Old 08-01-2009, 04:56 PM
  #5  
oups59
Three Wheelin'
 
oups59's Avatar
 
Join Date: Jan 2005
Location: Shefford,Quebec
Posts: 1,899
Received 52 Likes on 30 Posts
Default

The best wheel calculator I have found.

http://www.bigcustomwheels.com/info_specs.jsp

By the way, your car is very nice..
Old 08-17-2009, 01:09 AM
  #6  
Porsche Eye
2nd Gear
Thread Starter
 
Porsche Eye's Avatar
 
Join Date: Jul 2009
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Thumbs up

Got a look at the web site you suggested.
Here is my understanding:

OEM set up in FRONT:
57 ET - 5 spacer = actual 52.

New wheels
45 ET - 0 spacer. Only difference of 7 outwards so will clear the suspension
for sure, and should note rub the fender.

Same thing applies to the rear.

Thanks Oups.
Old 09-26-2009, 01:40 PM
  #7  
Spiffyjiff
Rennlist Member
 
Spiffyjiff's Avatar
 
Join Date: Nov 2007
Location: Maryland
Posts: 1,402
Likes: 0
Received 9 Likes on 6 Posts
Default

HELP! i am looking for a set of 19", matte black, street rims and am settled on a style like the champion RS171's which are out of my price range, so i need to compromise. i, too, am looking at the victor zehn's but i have a feeling they'll be too outboard. can someone please check my numbers/logic?

stock '06 997S lobsters: 19x8 ET57, 19x11 ET 67
new zehns: 19x8 ET45, 19x11 ET 55
i dont think i have any spacers (i.e. wouldnt i be able to see them if i did?) and i think this is the only offset they offer in that style/size.

so by the online calcs, wont that will be 12mm OUTWARD for each wheel?? and wouldnt that put the tire (or at least the curb-rash lip) right at or even a little past fender edge? i'm thinkin it's a little much.

or anyone have any cheaper suggestions styled like RS171's? someone told me about AMT tech 110.

penny for your thoughts...
Old 09-27-2009, 11:49 AM
  #8  
Spiffyjiff
Rennlist Member
 
Spiffyjiff's Avatar
 
Join Date: Nov 2007
Location: Maryland
Posts: 1,402
Likes: 0
Received 9 Likes on 6 Posts
Default

Originally Posted by Spiffyjiff
HELP! i am looking for a set of 19", matte black, street rims and am settled on a style like the champion RS171's which are out of my price range, so i need to compromise. i, too, am looking at the victor zehn's but i have a feeling they'll be too outboard. can someone please check my numbers/logic?

stock '06 997S lobsters: 19x8 ET57, 19x11 ET 67
new zehns: 19x8 ET45, 19x11 ET 55
i dont think i have any spacers (i.e. wouldnt i be able to see them if i did?) and i think this is the only offset they offer in that style/size.

so by the online calcs, wont that will be 12mm OUTWARD for each wheel?? and wouldnt that put the tire (or at least the curb-rash lip) right at or even a little past fender edge? i'm thinkin it's a little much.

or anyone have any cheaper suggestions styled like RS171's? someone told me about AMT tech 110.

penny for your thoughts...
anyone? anyone??
Old 09-28-2009, 07:26 PM
  #9  
JEllis
Pro
 
JEllis's Avatar
 
Join Date: Feb 2007
Posts: 732
Received 57 Likes on 44 Posts
Default

ET45 will either be right or just passed that edge of the fender. On a 11" wide wheel you will probably not want to go bigger than a 295 series tire to avoid any outside rubbing issues. ET48 to about ET51 is perfect on a NB 997.

Jason



Quick Reply: Help on offset calculations for new wheels



All times are GMT -3. The time now is 05:52 AM.