I am looking at getting wheels that are 16x7 +50 but would be switching out for 2" lips so the wheels would then be 16x8. I understand that offset is not exactly easy to calculate if you do not have the wheels with you to measure accurately, but I was hoping you guys could help me get a ballpark figure before I go and buy these. I know that offset is the distance from the center of a wheel to the mounting surface. Since the center of the wheel is going from 3.5" from the inner lip to 4" the only problem I may encounter will be rubbing on the outside. I was guestimating that I will be somewhere north of the equivalent of a 16x7 +25 but I have no idea if that is right or not. If I am mistaken in anyway please let me know, I am far from being a master at this stuff and would love to learn anything I can from you guys. Thanks again for all the help.

 

What kind of wheel?

If I understand what you're saying, you're putting a 2" lip on a 7" wheel with +50 offset. You didnt say what the current lip is. But since you said the wheel would then be an 8" wheel with a 2" lip, im assuming the stock lip is 1". So youre adding 1" to the street side of the wheel. That lowers the offset by 1" or 25.4mm. Giving you ~+24 offset. So the wheel would stick out about 1" more than they do now.

 

Offset is measured from the center of the wheel.

The center will be shifted towards the outside of the wheel by 0.5 inches (12.7mm) , so your wheel will be the equivalent of 8 inch wide, +37.3mm offset.

 

and if its a 3 piece wheel, and he is only adding a lip, which is adding 1" to the wheel, basically like pushing the center point 1" back, which would make alphalanos correct i believe

 

The center of a wheel is half its width.

1/2 of 7 is 3.5
1/2 of 8 is 4

The center shifts by .5", not by 1".

 

If its a 3 piece wheel that means the the lip is detachable, he's not replacing the entire barrel of the wheel, he's putting an entire inch IN FRONT of center

 

That doesn't change my answer whatsoever. Please go ahead and do the math.

 

ok so if his wheel started off with say a 5" back space and a 2" front spacing, it still has a 5" backspace, but now has a 3" front spacing, therefore pushing the offset of the rim 1" (about 25mm) lower

 

If you add X to the rim, your center will also change.

Let's say you have a 10" rim. 5" is the center. You have a +1" offset. You add a 1" lip. Your rim is now 11", center is 5.5". Your offset just increased by .5", not 1".

So as Phantom said, it gets halved.

So in your case w/ the 5" and 2" examples, the center is 3.5". If you add another 1" to the front, that makes the total width 8", making the center 4". The center just increased by 0.5" as well as the offset.

 

I calculate the offset in your scenario to be:

5" back, 2" front = +38.1
5" back, 3" front = +25.4

Works out to be a difference of 12.7mm according to my math.

 

correct. sorry about that.

 

i confused myself on this one, lol

 

Here maybe this might help you? Sorry pic is kind of small i can email who ever wants a bigger pic of figuring out backspacing and offset.

 

i have been personally changing lips for a while now on 3 piece wheels and i agree w/ phantom on this rule of thumb:

add an inch of lip to a rim(ie 1" lip will become 2") and the offset will go down by half an inch.

 

yeah sorry it took me so long to check back but the wheels are 3-piece and the lip on them currently is a 1". Thanks to everyone for your help on this I really appreciate everyone's input. So 8 inch wide, +37.3mm offset is what I will be looking at? Will this be anywhere close to flush or will I be tucking significantly? Thanks again!

 

you will be flushed but then you may rub as well at least on the rear. rolling your fenders might help and/or some negative camber depending on your ride height.

 

Thanks a bunch opposum and everyone else for your input it's been a huge help

 

what car is this going on?

 

EK hatch