Ordering new rims for my car soon and i've heard a few different things as far as the offset and one person claims i don't have it figured right.  so i'm turning for more advice.  The wheel i'm choosing is a totally different lug pattern so i need an adapter plate which of course adds thickness. based on what someone told me i think i have everything added correctly to make sure they will fit right.  My stock rims are 17x8.75 and have a 42mm offset.  THe rims i'm going to are 18x8.75 so same width but the offset they sell in either 20mm or 35mm.  From what i figured i'm getting a 25mm adapter plate which brings my total offset to 45mm, so they will stick out ever so slightly more which is totally fine i have the clearance.  Someone tried telling me a smaller offset wheel with larger spacer will bring the wheel in towards the hub which i don't believe is correct.  Can someone please help me figure this out before i buy my rims and have to return cause i did buy the wrong offset LOL.

Calculator above is perfect.

moose517
i've used those and according to what i figured as well i was right which is why i was confused.  that one is the one that said it would be 3mm wider.

Not 3mm wider but 3mm outset more from the hub, thats nothing to worry about. I hate, repeat hate lug pattern adapters. I've seen way too many go wrong. Ie lug failure, not hub centric and cause wheel offs.

Please please if you do use them check the adapter torque after 20miles(yes pull the wheels and tighten the adapters w/ factory torque plus a few ftlbs.) then retorque the wheels. I would even do this twice. 20years of working for goodyear and an independent dealer for experience.

moose517
Ordering new rims for my car soon and i've heard a few different things as far as the offset and one person claims i don't have it figured right.  so i'm turning for more advice.  The wheel i'm choosing is a totally different lug pattern so i need an adapter plate which of course adds thickness. based on what someone told me i think i have everything added correctly to make sure they will fit right.  My stock rims are 17x8.75 and have a 42mm offset.  THe rims i'm going to are 18x8.75 so same width but the offset they sell in either 20mm or 35mm.  From what i figured i'm getting a 25mm adapter plate which brings my total offset to 45mm, so they will stick out ever so slightly more which is totally fine i have the clearance.  Someone tried telling me a smaller offset wheel with larger spacer will bring the wheel in towards the hub which i don't believe is correct.  Can someone please help me figure this out before i buy my rims and have to return cause i did buy the wrong offset LOL.

Using an adapter doesn't bring the offset back to 45...it brings an offset of 20 to -5 and an offset of 35 to to 10....
 
http://www.willtheyfit.com/
This should be the only calculator that matters. Also to avoid confusion, make sure you mention offset as +35 or +20, as offsets can go into negatives. So to recap, offsets the further from the hub the lower they get. So if I am using say, +30 offsets front, and I add a 20 mm spacer, my offset is now +10 upfront.
 
Use will they fit above to figure out what offset you need.

moose517
ugh i'm just getting so confused by this crap, about to just say screw it and put rubber on my horribly dented rims and just say piss on it.  The rim has a +20 offset.  Using that calculator with a 20 offset shows that the tire will stick out 20mm more than stock, a 25mm adapter means it would bring it in to -5mm from stock then right?  If so that means i should be looking for a 15-20mm adapter plate?  Or a 5mm spacer??
 
EDIT: or rather +35 offset with the 25mm adapter plate and a 5mm spacer which if i'm correct would bring it to +5mm from stock total?  If so then thats probably what i'll end up doing.

Stop confusing the living crap out of yourself.......
Here is the math behind it:
The offset of a wheel determines poke from the hub. The higher the offset in the positive range the more SUNK the wheel will be in the wheel well, the close to 0 or negative the offset is the close the wheel is to the fender (or past the fender...).
 
Did you even bother with the calculator I linked? The one tells you how much poke you will get with a certain wheel...
 

I plugged in your stock wheels, and tire size along with the +20 mm wheels. If you read carefully at that offset you will poke 22mm more from where your wheel ends NOW. AKA your wheel will be 22mm close to the fender of your car. THIS IS BEFORE YOU ADD YOUR SPACER. AFTER you add the spacer you will poke an extra 25MM(if its a 25mm adapter/spacer). Which puts you a grand total of 47MM closer to the fender from where your stock wheel is at now.
 
PM me so you can get my number if you need to talk over the phone about it as it's easier to explain that way, or if you prefer PM over the thread.
 
I know this from experience as I had to figure out my own offsets/camber setup and tire/wheel gap from going from 17x7.5 all the way around to 20x9 to 20x10.



 

moose517
YEs i have used the calculator and thats where i'm getting more and more confused.  My stock tires are 225/50R17 with a 42mm offset and 8.86" width.  I want to keep the same overall tire height but with 18" rim which is where i settled on 225/45R18 and the rim i'm looking at has a 8.75" width.  They sell it in both 35mm and 20mm offset.  I have to have the adapter due to bolt pattern change and i'm only seeing them in 25mm.  I'd actually like to bring the back tires out a bit more from stock as the fender is a bit more out from the hub than the front.

Kay, here's the deal - go get a ruler. Measure currently how far you are from your rear fender(and front fender) to your wheel. Aka measure the gap horizontally from your fender to wheel.
 
The wheels you will go with are +35. @+35 you will be 7MM closer to the fender than your stock wheels. When you add the adapter plate that is 25MM that will make your offset effectively +10, and you will be a grand total of 32milimeters(25mm from the adapter, 7mm from the more aggressive offset wheels = 32) closer to the fender than your current stock wheels. If you can fit an extra 32MM compared to the gap I asked you to verify early, you will be able to fit the wheels just fine. (i personally poke 3mm and my wheels tucks when the car has passengers and has 2mm of clearence when under load between wheel and fender(i can't even fit a key))
 
 
 
This is what you should measure fender lip to wheel (in this case his doing hub, but you need to do wheel, so we can figure out if that 32 mm differential that comes from the offset of the wheel 7MM and 25MM added by the adapter, will clear fender without your wheels poking stupidly past your fender)

hey moose i'm with wrinvert if you go with adapters do a retorque at 20 to 25 miles and again at 100 to 150 miles i did 10 years at a independent tire shop and when a wheel comes off it is not pretty most times.

I'll have to measure in the AM after i find a ruler but just thinking thinking i don't think there is 32mm between the front of the rim and the fender, not on the front at least.  and right now my car is sitting up but i plan on lowering it at some point as well.  ANd yeah that 205 was a stock setting on the calculator, i've got 225's on my car now.

yeah lowering won't be till next spring at this point due to the fact that its getting to snowy season, i need tires now though as mine are pretty much at slicks and the previous owner coupled with an accident i had earlier this year left my car wit mis matched and very dented rims that i just want to replace.  I guess i should have started this thread before i ordered as i have a rim on the way already, of course when i asked someone they told me the +20 was what i needed and after having ordered it more than one person said ti was wrong which is why i started this thread in the first place.  Guess i'll have to eat that return cost :(  And i guess thats provided its even do-able after checking tomorrow.

Quick look when I got to work using my lunch box to estimate and it does look there is right about 32mm right now. I'll still measure for sure tomorrow but I think I'll be fine if I return the +20 for the +35

Getting xxr 527's in flat black. Seeing as I'm buying a camaro in a years time I didn't wanna put that much into rims but it needs done. Plus its a Pontiac g6 nothing too fancy

Ok Holo, finally got around to measuring and from the outside of my rims now to the fender is ~20mm on the front and back was more like 10mm :(

moose517
Ok Holo, finally got around to measuring and from the outside of my rims now to the fender is ~20mm on the front and back was more like 10mm :(

After lowering the car, front's will be fine. The rear is going to be a tough fit without some camber, and even then, post lowering the car, you're looking at 2-3 degrees of negative camber to fit. Honestly, if you are changing cars ina year, keep the stocks, fix the bent rim, return these wheels, and pocket the cash as a down payment down the road.
 
And next time figure out offsets before hand so you don't have to run spacers/adapters - buy the right wheel the first time to avoid these hassles.

moose517
I'm keeping this car... Camaro will be my fun car this is my daily driver. One of the rims is beyond fixable and another is proabaly right there. Guess I am just gonna return the crap and put rubber on them bent or not.

Go on craigslist and find some replacement(oem) from someone selling their stockies.