Paging Dr. Design: Wheels question...

ruf455 · #1 (**permalink**) 06-03-08, 08:34 AM

...and anyone else who can answer.

I am picking up my STS in a couple of days. I would like to run as wide a rear tire on an 18" wheel as I can (275/40/18 - 26.8" tall). I have seen D3 cars with some serious meats on the back. What back space/offset are these wheels running to achieve proper fit? I have seen the 295/30/22 and they have a hell of a section width, so a 11" section width tire should fit with the proper backspace/offset. I am planning on buying after market 18", so I can choose a wider set in back than in front. I already determined I could run a 255/45/18 up front on a stock offset/backspace. So the question is: What is the stock offset/backspace and what kind of offset/backspace do I need to run to fit a 11" wide section width tire?

I've seen lots of photos, but I can't find any hard specs.

ruf455 · #2 (**permalink**) 06-04-08, 11:54 AM

Ok, standars 18's are a 42mm offset, STS-V rear 19's are 52mm

Not many 5-115 wheels out there. Lots of sights claim that the 5-4.5/5-114.3 will bolt up and fit. Any thoughts?

C&C · #3 (**permalink**) 06-04-08, 02:26 PM

It's been discussed on other threads. My take is that 114.3 is not 115; no, they don't fit.

0.7 mm is almost 28 thousandths of an inch. A piece of paper is approximately 3 thousands of an inch, so 28 thousandths is approximately a stack of 9 pieces of paper thick. That is a pretty big difference between fitting and not fitting.

ruf455 · #4 (**permalink**) 06-04-08, 05:14 PM

sheeesh...lots of wheel suppliers selling 114.3 to bolt up to our cars....

Dr. Design · #5 (**permalink**) 06-04-08, 06:02 PM

Hello,
Well I guess it really depends on what type of wheel you are going to use. some wheels can run more offset because they have a more "bowed" face. There are some members on these boards that have wheels like this. They can run a much wider lip because of the contour on the face of wheel allows for more clearance. If you are running a 2 or 3 piece wheel you will have a few more options as far as offsets are concerned.

If you are running a 18" tire you should be able to easily get a 295 in the rear.

Thanks,

Dr. Design
D3 Cadillac

Quote:

Originally Posted by ruf455

...and anyone else who can answer.

I am picking up my STS in a couple of days. I would like to run as wide a rear tire on an 18" wheel as I can (275/40/18 - 26.8" tall). I have seen D3 cars with some serious meats on the back. What back space/offset are these wheels running to achieve proper fit? I have seen the 295/30/22 and they have a hell of a section width, so a 11" section width tire should fit with the proper backspace/offset. I am planning on buying after market 18", so I can choose a wider set in back than in front. I already determined I could run a 255/45/18 up front on a stock offset/backspace. So the question is: What is the stock offset/backspace and what kind of offset/backspace do I need to run to fit a 11" wide section width tire?

I've seen lots of photos, but I can't find any hard specs.

ruf455 · #6 (**permalink**) 06-04-08, 09:37 PM

Quote:

Originally Posted by Dr. Design

Hello,
Well I guess it really depends on what type of wheel you are going to use. some wheels can run more offset because they have a more "bowed" face. There are some members on these boards that have wheels like this. They can run a much wider lip because of the contour on the face of wheel allows for more clearance. If you are running a 2 or 3 piece wheel you will have a few more options as far as offsets are concerned.

If you are running a 18" tire you should be able to easily get a 295 in the rear.

Thanks,

Dr. Design
D3 Cadillac

Thanks, you made me feel better about fitment. I am not shopping a huge lip, but if it happens, great. I have found a couple one piece wheels with 45mm offset (18x9.5) that will work just great out back and I can stick with a 40mm up front on a 18x8(.5). I am going 275/40/18 on back 255/45 on up front. I will post pictures when I get them on. I have to sell my Joe Gibbs SS wheels first...maybe. I will have some nearly new Continentals on stock 17"'s posted up for sale when I get the new wheels on.

C&C · #7 (**permalink**) 06-05-08, 05:23 AM

Did the question change? The 114.3 versus 115 has nothing to do with offset; it is the dimension between the lugnut holes.

ruf455 · #8 (**permalink**) 06-05-08, 08:49 AM

Quote:

Originally Posted by C&C

Did the question change? The 114.3 versus 115 has nothing to do with offset; it is the dimension between the lugnut holes.

Nope... my original question was all about offset and wheel/tire width. The bolt circle question popped up when I saw HUNDREDS of wheels listed to fit the STS with 114.3 bolt circle and EVERY wheel tech I spoke with SWORE that 114.3 works wtih our hub centric mounted and supported wheels. They continued to make the case that there is more than enough [i]slack[i] in the lug holes that it works just fine.

Unless it was a custom job: I've seen D3 cars with a 5Zigen Gravis wheel that is NOT available in the 5x115 (5x114.3 instead). Ask and I bet it they did not fall off in a blaze of destruction...

I'd be curious to see a picture of somthing LESS than a 20" with a 10" tire out back....

C&C · #9 (**permalink**) 06-05-08, 11:18 AM

I stand corrected; your second post mislead somewhat, there is where I picked up on the lug spacing scenario.

ruf455 · #10 (**permalink**) 06-05-08, 02:47 PM

[quote=C&C;1538685]I stand corrected; your second post mislead somewhat, there is where I picked up on the lug spacing scenario.[/QUOT

No worries! I am going to the wheels store to test fit a 114.3 and a 115 to see what all the fuss is about....even though it has been covered here already.