rotorooter93fd

iTrader: (6)

thanks dave if i get permission from the modcity.com to post their wheel fitment guide then i will go ahead and post it so you guys can see what im talking about, in the mean time does anyone know what the factory wheels offset is for sure and also are they 16x8 or are they 16x8.5?

joe_yoh

I'm kinda confused about your post man...And your pics are not that good...

Mahjik

iTrader: (1)

1993-1995 USA OEM wheels are 16x8 +50.

David Hayes

iTrader: (6)

I asked this earlier in the thread, but what does the +50 mean? Is that in centimeters or a metric measurement? I understand the plus and minus of offsets, just having difficulty with the 50 part.

94RHDFD

iTrader: (3)

+50 is the stock offset

David Hayes

iTrader: (6)

Yes, I know, but what does the 50 equate to? Is that 50 centimeters? Millimeters? Or something else?

David Hayes

iTrader: (6)

Okay, I think I have this figured out. Per the following website:

https://www.rsracing.com/tech-wheel.html

So, for example, my front wheels are 8.5 inches measured from the inside of the rim. So, 1/2 of this is 4.25 inches. My measurement from the backspace to the inside lip of the rim is 6.5 inches. Because my backspace is greater than my center measurement, I have a positive offset and it is 6.5 inches minus the 4.25, or 2.25 inches which converts to (in millimeters) a +57 offset.

My rears are 12.5 inches measured from the inside of the rim which is 6.25 to the centerline. My backspace measurement is 7.625 inches so again, I have a positive offset which is 7.625 - 6.25 or 1.375 inches or a + 35 offset in millimeters.

Experts correct me if I am wrong on this.

rotorooter93fd

iTrader: (6)

damn quantum physics! i didnt even do well in college algebra!

David Hayes

iTrader: (6)

I know! Thought it was a simple inch to metric thing but apparently not At least now I know how to measure offsets.

allrotor93

iTrader: (126)

I had 18x12 +18 with Pilot Sport 335s and it was a perfect fit

ARD T2

iTrader: (22)

STELLAR WORK DAVID, VERY VERY VERY PROUD OF YOU.

HOPE THIS MAKES YOUR WEEKEND EVEN BETTER.

ABSOLUTELY GREAT

BUT ONE ISSUE.

the true definition of backspacing should be to the outside of the lip. Total spacing when done this way is measured from outside to outside for checking fender and suspension clearances. This is simply semantics but what you did in calculations is correct.

.

As long as you measured from the inside of the lip to inside of lip and did same with backspacing you are good to go.

Honestly though you should still be able to derive the same offset by measuring total spacing from outside to outside of the lips, PROVIDED the lips are both the same thickness. This means your "centerline/point of origin" should remain unchanged, both backspacing, and total spacing values will increase to offset each other.

This is helpful if a tire is already mounted on the wheel.

i.e.

8.5" would be 9.5" wide outside to outside. Adding 1/2" lip rim thickness to each side. This means your backspacing value will also increase by 1/2". wink wink.

So
9.5/2 = 4.75" = center.
Backspacing = 7.0"

7-4.75 = 2.25 = the same answer you got.

Rishie

rotorooter93fd

iTrader: (6)

thanks again rishie. guys i wanted to comment as well. i called rishie the other day and even though i didnt order from him he still helped me. I can say without a shadow of a doubt i will be ordering exclusively from him from now on.

radicalmark29

sick as fuuuuuuuuck

ARD T2

iTrader: (22)

My pleasure. Lord knows I did try to find something in the style you like so it wasn't a completely selfless act. lolz.

David Hayes

iTrader: (6)

Also, thanks for the expert correction to my calculations as I really don't know what I am doing. I'll rerun the calcs as my backspace measurements were to the outside lip so that will change things.

rotorooter93fd

iTrader: (6)

yea the guys at iconz still cant figure out what im teeling them if they cant figure it out this week they can forget the order and Rishie will have a new order lol. at this point i almost hope they **** up. lol. now i just have to go over the measurements again with them. i hope i can find the measurements that Rishie gave me.

allrotor93

iTrader: (126)

Here are 18x12 AutoArts (from rishie of course ) +18 with pilot sport 335s

ARD T2

iTrader: (22)

Oh so sexy.

ok rotor, just cancel the order with them and compromise on a style I can get.

I can't believe they can't figure this **** out. If they can't figure this **** out "WHY ARE THEY MAKING WHEELS?". Seriously lame, i thought this was all handled.

I think I can figure out the measurements i told you. they are in an email somewhere.

Rishie

gawdodirt

Ok now. This starting to hurt my head. 50 centimeters is 500 millimeters. 100 mm is about 4 inches. Could it honestly be 20 inches of offset?

50 mm is about 2 inches, so I'd guess that this is in mm.

Also, "rim width" for tire fit is always inside to inside. Even measured in inches.

gd

ARD T2

iTrader: (22)

OK so let me clarify this offset thing real quick.

+50 is in units of "mm". Almost 2".

+0 = centerline of the wheel

The more positive the offset means the more "sunken" or pushed in the wheel will appear. i.e. moves closer to suspension and farther away from the fender.

The only logical way to do this would be to "machine" material away for the centerline, thereby pushing the wheel inward. The distance of this "machining" is the offset whether measured in mm or inches.

However 99% of wheels out there have offset measured metrically in mm.

When inches are used that is typically done in reference to front and backspacing. By obtaining both front and backspacing values you can interpolate the offset in inches and then convert metrically to mm if you want to produce the equivalence.

We've gone through some of those calculations above. It's definitely not rocket science or quantum physics. You guys just need to see its practical application.

Rishie

ARD T2

iTrader: (22)

So if you guys want a broken down example.

FD OEM 16x8 +50.

8" Wide from inside of lip to inside of lip = total spacing that the tire can consume within the lips' walls. Tryin' to be laymen here.

9" wide from outside of lip to outside of lip = Total outer spacing of wheel.

We'll work with the 9" measurement since that's more practical when building a custom wheel and taking clearance measurements under the car.

So at 9" TS, Centerline is at 4.5". Now if it has 2" of offset = 50mm then

2.5" is the amount of front spacing and 6.5" is the amount of backspacing. Making a total of 9" in spacing.

RULES OF THUMB

TS = Total spacing
FS = Front Spacing
BS = Back Spacing

IF FS < BS = POSITIVE OFFSET
IF FS > BS = NEGATIVE OFFSET
IF FS = BS = ZERO OFFSET

Rishie

rotorooter93fd

iTrader: (6)

rishie are there any manufacturers that you work with that can make copies of iforged sprints wheel line so i can just ditch the jokers and give the you my business instead?

ARD T2

iTrader: (22)

Unfortunately i haven't been working with many domestic manufacturers. the only company I would want to work with is Forgeline in terms of 18" wheel options. I've had problems with a lot of "custom" wheels that are made in socal. Miami is popping out some real nice stuff in this segment but they are all 19" and up I think.

Check forgeline, i think they have a style you like.

Rishie

rotorooter93fd

iTrader: (6)

all rotor are your 18x12's acatually 18x12 or are they 18x13 when measured outer lip to outer lip.

ARD T2

iTrader: (22)

lol, Oh man we're just causing more and more confusion here.

Ok so any normal laymen person is going ot use the "inner to inner" lip since that's what is printed.

So allrotors wheels are 13" in total spacing but considered 18x12's when written in this format: diameter x width

For Japanese wheels we don't have to worry about all that crap. It's so much simpler.

Rishie