hey guys just started reading up on wheels and offsets........and boy i am lost. i really want to purchase the gram lights 57 pros but am not sure what offset/size to get. i want to get the 18x8 or 18x8.5 but am not sure of offset/rubbing/fitment issues.

ideally i would want the same look as the wheels on Apexi's D1 machine. here is a picture.



here are the specs that they give on the Apexi RX7.

BRIDGESTONE Potenza 235/40R18 Front Tires
BRIDGESTONE Potenza 265/35R18 Rear Tires
RAYS GRAM LIGHTS 57PRO 9JJ-18 off+38 Wheels (front)
RAYS GRAM LIGHTS 57PRO 10JJ-18 off+22 (rear)
Front 20mm Spacer

the specs on my car are as follows.

BRIDGESTONE Potenza 225/4018 Front Tires
Kumho ECSTA MX 225/4018 Rear Tires
Espelir Springs ~1.5 inch drop

does anybody know if this setup will fit on an rx8? i dont really need a rim as wide as 18x10, id be okay with 18x8 or 18x9. but if the rim isnt as wide, does that effect how much of a dish i can get with my wheels? any help is greatly appreciated. thanks.

 

My 18x8 +40 offset fits perfectly. With the 245/40/18 tires, and a slight drop from stock with the RB springs, I've never had an issue.

 

I was confused by offset as well. What I was told is that the smaller the offset, the larger the lip. So, a +36 offset would have a smaller lip than the same sized rim with a +22 offset.

Another piece of information I was given is that the RX8 can fit rims with offsets ranging from +35 to +46.

You should be able to fit an 18 x 8.5 rim, depending on the manufactorer. Just for instance, the largest Volk I could fit in the rear is 19x9.5, while buying a similar set of Racing Harts I could have fit a 19x10.5.

I hope that helped....I guess you'll have to go and actually look at the rims you want...and then ask the salemans if there is any way of ordering one with less offset (greater lip)....some rim companies don't make many sizes, so you're stuck with what they make.

Another example. I met a guy who had the Volk GT-7's in the silver finish. His rims were 19x8.5 (+36 offset) and 19x9.5 (+36 offset). I loved his setup and went to buy a set for myself...only in the diamond black finish. I was told that this finish didn't come in the same sizes. The closest I could get was +40 offset.

 

http://marksink.com/tire_wheel_offset/offset.html

remember that a lower offset than stock will place more of the mass (and more importantly more of the upward counter force) away from the ideal location in relation to the rest of the suspension. 350zs, and g35s have lower offset wheels from the factory, so they are better able to have bigger lips. the rx8 has very well calculated suspension geometry, so you'll be paying a performance cost in favor of looks. you also risk rubbing, but some negative camber can help that out if a big lip is that important to you.

just get a level and measure straight up from the side of the tire. mark that point and mesure the distance from there you the part of the fender that would looks as though it may rub. you'll get more distance as the suspension compresses due to camber, but that should give you an idea of how much clearance you have.

 

so the lowest offset an rx8 can possibly have regardless of wheel width is +36? i really want the deep dish look. so a wider wheel will not let me have a bigger lip (lower offset?).

i used the offset calculator u provided and enterted in a new wheel width of 8.5 with an offset of +22. this is what i got.

Your new wheel will have the following chracteristics:
The clearance from stut housing to the inside of the wheel will be 22mm MORE
The outside edge of the wheel will EXTEND an extra 34mm

is that totally gonna look weird or mess up my susp. geometry?

 

my tenzo GT-05 have a 30 offset for the rears 19x 9.5..

and before anyone starts flaming me on why i went with tenzos instead of the volks...simple answer:

i dont have the ridiculous amount of cash that most affluent RX-8 owners have.. i bought what i deemed fit for my car within my budget.

 

RX4life.......if you could post some pics of your rear wheels it'd be greatly appreciated.

tenzos are great, cant wait to seem em.

 

the rear is less of a concern than the fronts +36 should be ok in the back, but i'd go higher in the front..

 

if you want big lip for the Gram Lights 57-Pro...

front: 18x8 +30
rear : 18x9 +22

tire sizes...

front: 225/40-18
rear : 235/40-18 or 245/40-18

probably need to roll the rear fenders if you lower it with coilovers.

i got this based on the 57-Pro fitment chart http://www.rayswheels.co.jp/cgi-bin/...odelName=57PRO

 

what if im lowered about ~1.5 inch springs? will i still need to roll my rear fenders?

also......are u sure that the rear: 18x9 +22 offset will fit? the general consensus in this thread seems to be that the lowest offset possible on the rx8 is a +36. i really want the +22 deep dish but i want to make sure its even possible.

 

unfortunately im not gonna have them on till spring...over the winter i will have my rear fenders rolled/cut whatever seems fit and cheaper according to a bodyshop.. then bolt on the tein basics from injected performance.. and then slap on the Gt-05s just in time for the sun... i will have pics for you by then!.. personally i see as extra "4 mm of sticking out" not to be that much of a problem.. infact i love the LOOK of 'drifter status' with crazy offsets and really wide bulging wheels!! :D

 

1 inch = approx. 25 mm

let's say there is about a 1.5 inch difference between the rear fender and outer part of the rim. by upsizing to a 9 inch wide rim, you are adding .5 inch to each side of the stock wheel. .5 inch = 12.5 mm, so now we have a difference of about 1 inch (25 mm) between the rear fender and outer part of the rim. by using a +22 offset instead of the +50 of the stock wheels, you're pushing the outer part of the rim 28 mm. since we have an 1 inch left to the rear fender 28mm is going to be sticking out about 2 mm more than the fender. 2 mm isn't even the width of a half used check book.

now with an 1.5" drop, you might have rubbing issues if you used wider tires. so i say with a 18x9 +22, you should use a 245/35-18

 

the fronts:

about 1 inch diff. between front fender and face of stock rim. with an 18x8 wheel, you are keeping the same dimensions as the stock wheel. but with a +30 offset, you are going to be pushing the rim out to 20mm. so the rim would be stick inside the fender about 5 mm.

you could go with a 18x8 +22...but it would be just like the rear and stick out a tad. i'd go with a 225/40-18 tire.

 

the front size 9" 38+ is a good fit. don't use the spacer on the front.