Ok so I was looking at RO_JA Formula 7 and on 350zonlinestore.com. The wheel soecs are Front 19x8.0 +25 offset and Rear 19x10 +30 offset. But on the website it said it needs a small spacer in the front to clear the brembos. I e-mailed 350zonlinestore about this becuase just about everyone here buying 19' volks and other rims are getting a +25 offset.

When I got the e-mail back he said the fron needs just a +5mm spacer to clear... but if the stock has a +30why wont these clear? In his e-mail he mentions the stock 18s using a +30 offset to over compensate, but wouldnt a +25 push the spokes further from the brake than the +30 stock? can somone help me better understand what this means? Just incase you lost me.. here is the page that the rims are on

Formula 7's

and here is the e-mail I got back from them after asking about the spacers.

"Matt- The Ro_JA Formula 7 package will fit the G35 coupe the same way
as the 350z. The front will not clear the brembo front brakes andthey
will need a small 5mm spacer to help the brake caliper to clear the
spokes. We ran a small spacer on our project car and they work out fine
to clear are up graded big brake kit.

The stock 18 are a plus +30 offset to over compensate and to make sure
that you will not ever have any clearence issues. The factory uses very
mild offests thats why the stock rims look a little tucked in.

The reason these Ro_JA rims offset are different is because they bring
the rims to look more flush with the wheel well. Also they are done
this way to give the rims a big lip in the front and rear.

Hope this answers your questions."

In a nutshell im asking why the 18x8 +30 offset (stock g35 rim) will fit and the ro_ja 19x8 +25 offset rim wont work becuase the lower number you go, the further away the spoke get from the brakes?

 

You are correct about it being more flush with the fender, but I don't think offsets tell the whole story. There is probably a decent size lip and that is my guess why they won't clear.

 

Spacers are sometimes used for non-customized wheels, but what you get is a better price, so it's your call sometimes between expensive customized wheels (so you don't need to deal with any problems) and lower end wheels (so you have save $$$ for other mods).

good luck, man, please show pictures after done w/ and w/o spacers for our referrence

 

It may have something to do with the disk type. What the actual shape of the spokes are. Alot of the Japanese wheels are avail in different disk types. I'm hoping some one else can chime in on this who knows a bit better. I still don't quite understand the different terms for the disk. Take a look at this.
http://www.fabulous.co.jp/wheel/list/disk.html

 

You are exactly right. Eventhough the Ro_Ja formula 7's have a lower offset than the factory wheels, the rotor side of the spokes on these wheels have very little curve to them to allow for enough space to clear big brake calipers. My friend bought thse wheels for his NSX and he also had to put a 5mm wheel spacer on to clear the calipers. It's really not a big deal to put a 5mm spacer on since you don't even have to get longer lug bolts. They are good looking wheels though.

 

yeh, the disk type and spoke design does make a huge difference.
a 5mm spacer is okay to use on your stock lug studs. Just don't
track the car with it. If you do track your car, use longer studs...
which is a simple fix any Inf/Nis dealer can do for you.