Offset Question

wnsgc · 03-23-2009, 07:34 AM

Greetings,

Question regarding offsets. I have an 85 911 Carrera with 16x7 and 16x8's. What are the offsets required for these, and how do I tell a Fuch has the proper offset? Can I go by the number stamped on the back? Also, if I switch to 16x6 and 16x7's, do I use the same offset?

Thanks.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by wnsgc

Greetings,

Question regarding offsets. I have an 85 911 Carrera with 16x7 and 16x8's. What are the offsets required for these, and how do I tell a Fuch has the proper offset? Can I go by the number stamped on the back? Also, if I switch to 16x6 and 16x7's, do I use the same offset?

Thanks.

For an SC
front 7 - ET23.3
rear 8 - ET10.6

Yes, these are on the back of the spokes

front 6 - ET36
rear 7 ET 23.3

450knotOffice · 450knotOffice's Garage

I posted an answer, but just noticed that the master has already answered you. Bill is the resident expert here when it comes to wheel fitment issues.

T77911S · 03-23-2009, 08:25 AM

the numbers on the back side tell you the size and offset. ET15 is 15mm pos. it is referenced to the center line of the wheel. poistive moves the hub of the wheel out which moves the wheel inward, makes the track narrower. if you go down an inch in width, that will be like a 1/2 in off the inside and a 1/2 inch off the outside of the width, as long as the offset stays the same. you would need almost zero offset to make the outside of the rim equal to the same distance from the fender as the original size, or you could add a 1/2 inch spacer. 25.4 mm = 1 inch

wnsgc · 03-23-2009, 10:13 AM

Thanks for the reply folks. Bill's response is for an SC, I assume its the same for a Carrera. If I go from a 16x7,16x8 to a 16x6, 16x7 (front, rear), it sounds like I have to find offsets of 36/23.3 (front rear).

Do I have this right?

wnsgc · 03-23-2009, 10:15 AM

Oh, one more question. Are there different offsets for the Fuch sizes? If I'm looking to buy 16x6 and 16x7's for my 85 Carrera, do I need to check the offset, or is there typically one size offset?

450knotOffice · 450knotOffice's Garage

Yes, the SC and Carrera use the same offsets.

16X6 has only one offset, I believe. 16X7 might have a couple.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by wnsgc

Thanks for the reply folks. Bill's response is for an SC, I assume its the same for a Carrera. If I go from a 16x7,16x8 to a 16x6, 16x7 (front, rear), it sounds like I have to find offsets of 36/23.3 (front rear).

Do I have this right?

any 911 w/ SC/Carrera fender flares from '69 thru '89 is going to use the same wheels.
6 x15 or x16 all have ET36
7 x15 or 16 w/ 911 or 951 part #s all have the same ET23.3, the 951s just have more brake clearance. Any of these fit front or back
8 x15 & 911 8x16 all have ET10.6 and only fit on the rear of an SC/Carrera flared car
8x16 951 wheels have ET23.3 and can be fitted on the front also have bigger brake clearance, they need spacers to work in back

9x16 all have ET15 and only fit in back

wnsgc · 03-23-2009, 05:51 PM

Bill,

I appreciate the information, you are the wheel deity. I currently have 16x7 / 16x8 on my car, however the PO had the wheels chromed (lips and paddles) and they are now starting to flake. The cost of stripping them and refinishing them is outragous. The cost of a direct replacement with the standard look (anodized lips and black centers) is fairly high, but I'm finding 16x6 / 16x7 all over the place with decent prices. I drive one DE event a year, but I don't push the car, it's just for fun, I mainly enjoy the roads with it, thus I'm not sure if I need the 7's & 8's.

Thanks for sharing your information and knowledge.