I'm getting my first Mini this week (not-so-patiently waiting for the loan docs to arrive) it's an '05 MCS.

After spending way too much time looking through what must be a thousand wheels I've narrowed it down to two.

Wheel #1 is 18x7.5 offset 42
Wheel #2 is 18x8.0 offset 45

I plan to use BFG G-Force Sport tires in 215/40/18. I like the way the 40 looks on Minis vs. the 35, not to mention the better ride quality as a bonus. Also, I would like to use the H&R springs, the ones that only lower it 1.0" front & .75" rear so that's just a slight drop.

My question is would Wheel #2 which is 8.0" wide w/45 offset fit fine or should I be safe and get Wheel #1 which is 7.5" wide with a 42 offset? I haven't shown a picture of either wheel because I don't want that to sway opinions. :impatient

 

#2 should fit... 8in = 203mm and i know my 205/50/16's GSD3's on
7.5" width wheel is much wider than 8inches. running +43mm offset
very flush but no rubbage.

 

Your clearance will be very close to rubbing if not be rubbing.
Problems-
Both rims are wider than stock 18x7
215/40-15 is taller than stock at 24.8+"
Your drop is unknown until you actually install it and it might be lower than you think- it does vary a little.
An important element you didn't mention is will you have front adjustable or fixed camber plates and lower rear adjustable control arms (your 2005 MCS will have a mild adjustment nut on the lower control arm already)
You can increase negative camber front and rear to give you a little more clearance.

So wider tires on wider wheels with similar offset to stock means more wheel and tire face the inside and outside of the wheel well and a drop means less clearance on the outer edge of the rear wheel.

Safer would be 215/35-18 for more clearance. 24" tire diam.
Stock is about 24.3"

Also anytime you go wider than stock you usually have to go with less offset. So for example 15x7 is about +38 offset, 15x8 is about +33 offset.
If you have 15x8 with +40 offset it will rub the rear lower trailing arm in all MINIs new or old.

Be prepared to use spacers if rubbing the inner suspension parts- shocks or rear swaybar or use a dremmel tool to trim the inner rear wheel arch plastic.

 

minihune, thank you very much for that information and taking the time to type it out for me.

The good news is that I looked through the 161 page thread about "show me your wheels" and I determined that the style of wheel that I picked out in 8" wide doesn't look good on the Mini. So my 7.5" wheel is what I'm going with; my favorite look on the Minis is either a 7 or 10 spoke wheel.

Regarding your question about camber plates or control arms... I'm not sure. My plan was to put the wheels/tires/springs on the car and then put it on the alignment rack and see if camber adjustment was needed front or rear and then go from there. I'm a tech at a Honda dealer and I do alignments on a daily basis so that is something that is really quick and easy for me. This is just going to be a normal street car, no racing or autocross, so therefore I'd rather not dial in any extra negative camber and wear out the inside edges of my tires for the sake of better cornering or tire clearance.

My main goal is I don't want the "two finger gap" between the top of the tire and the fender lip. I don't want to totally slam the car with the tire tucked inside the fenders but I don't want the gap either. I don't have any problem with doing some triming, I've had a lot of lowered cars in my time so triming is something I expect. I don't really like the idea of the 35 series tire so much and I hope I don't have to go that route. Thanks again for your help!