Philostang

Hey-lo All,

I was thinking that some things recently said might be confusing for those trying to figure out what the proper offset and size tire/wheel to run. Maybe not, but just in case:

1. "Deep Dish" is a non-technical term that generally denotes a wheel with a wide lip. For any given wheel width, the "deepness of the dish" will be determined by two things, design style and offset. Our very own fairlane292 repeatedly posts an excellent explanation of offset with links (his most recent is found in "RE: Ohh no! new wheels stick out! help."). The bottom line is that for a given design and offset, there is no extra change in the wheels mounting that would result from wheels being "deep dish"--they'll either be deep or not once you figure these two other factors in.
2. Stock 18" wheels have +50mm offset. With their 8.5" width and tire combo, they sit about a full inch inside the fender (about 7/8" inside the inner lip of the fender--Ford rolled the fender lip for us!). If you went to +45mm offset, that's less than a 1/4" increase towards the fender (6mm is roughly 1/4").
3. For any increase in wheel width, you divide by 2 to figure the increase on each side. Then add in the increase or decrease from any offset changes, eh wallah! You get your new wheel placement.
4. In the case of 18x10" with +45mm offset, you end up with 3/4" extra on each side from the extra 1 1/2" width, add the (less than) 1/4" and you get a bit less than an inch. Factor in the larger crosswidth of the 275/40s, and you end up with a little over an inch outboard increase. This is what it looks like in the image I posted above. It shouldn't come way out of the fender, but sit flush to a maybe a tad out.
5. Spacers are going to directly impact where the wheel sits in the wheel well--so if you go with the 18x10"s I just described, and you go with 1/4" spacers, well then you have a recipe for a wheel that sits 1/4" further out than the image you see above. Personally, I think this would look silly on our cars. You would need a wheel with +50-55mm offset to make this sit flush.
6. I've posted this before, but it's useful to use Rick Tolan's tire/wheel calculator: http://gs.tolan-hoechst.com/tirecalc.htm Unlike wheel placement, the combo of wheel/tire is not so easy to calculate, so this has helped me out, and I've confirmed its results in a number of other cases (although, it sould not be taken as gospel, only a good guide).
7. The blue car definitely has F1s.

Best,
-j

Menace

The spacer isn't for a 18x10 wheel though. It's for the 18x9 wheel. To me this is just giving me the impression that it's sticking the front wheels out enough to match the back wheels?

fairlane292

Philostang: FRPP site wrong ??? FRPP shows the backspacing on the 8.5"rim as 6.295"backspacing, the same as the 8" rim. Now if they wanted to evenly distribute the half inch over over each side of the bolt face, thus increasing the backspacing by 1/4" they would have increased the offset from 45mm to 50mm. ...but according to the Ford site they did not increase the backspacing. As you know when you increase positive offset you push the rim inward; meaning the 1/2" would have been evenly shared inward and outward of the bolt face with the 50mm offset. Is the FRPP site wrong on the 6.295"backspacing on the 8.5"rim?

M-1007-U1885
5-lug, 4.5" bolt circle

6.295" backspacing

18" x 8.5" wide


M-1007-T178C
5-lug 4.5" bolt circle

6.295" backspacing

17"x8" wide

Philostang

YES!

Oh, I feel like a man vindicated. You are exactly right on what Ford did to redistribute the extra 1/2" on each side. Unfortunately, as has happened in the past, the FRPP site listed incorrect information (they once listed the Big Block Ford as the same weight as the 351). Fortunately, Ford engineers are smarter/more reliable than their graphic designers. They cast the wheel figures into the back of the spokes, so you can confirm this straight off the 8.5" wide wheel. Here's a picture of the back of mine.



[IMG]local://upfiles/28883/A6577ED8C7A0497AB7CEB6A6ED9D32F1.jpg[/IMG]

MTShambles

Not quite. The front wheels were cut a bit too short as far as offset goes. The caliper rubs up against the spoke and the inner barrel. The company that we get those from (topline products) recently had to get new wheels made with the new offset.

Now what I can tell you...(shhhh dont tell anyone else ) is that the container with the resized 9" rims JUST came in on Thursday. I have a limited stock right now...so if you want non spacered wheels, nows the time to grab them .

And if anyone asks, a little birdy told you .

fairlane292

Nice!!!! I kinda figured the site was wrong and even distribution with 50mm made more sense; Thanks for confirming this!!!! ...Jim

evil_stang

I just got my 18x9s and 18x10s deep dish wheels Friday and they did not contain spacers for the front wheels. When I called, they told me that the wheels were re-designed so no spacers were necessary. I haven't had a chance to order tires yet, but these rims look nice sitting in my garage! Can't wait to see them on the mustang!

Just FYI, I did not care for the standard center cap that came with the rims, so you might want to order some new center caps too!

fairlane292

Bolt one on the front (and rear) before you get tires mounted!!!!! Once mounted there's no return. You can even determine how far out they are over oem before you get tires mounted. Enjoy!!!

trey929

OK correction, my deepdish rims look great and they don't stick out. my correction. my only issue now is, i'm not crazy about the look of the deep dish rim in the front? Would standard dish of looked better?