Tried to search for it but couldn't find anything:
What are the pro's & Con's of each size, ride + handling + gas mileage?
Same style/brand of wheel...

 

There are many many threads on various pros and cons of each wheel size.

Usually they will compare two sizes not three.

16" is your best bet for light rims, low cost, good enough looks, good selection, good tire sizes to choose from.

16x7 rim +40 to 45mm offset
205/50-16 or 205/55-16 sizes (later is slightly tall at 24.9")

15" also a very good size you did not mention. Same benefits but doesn't always fit over JCW front brake calipers. Make sure each wheel is compatible with TPMS and with 14" bolts for newest MINIs, otherwise they will fit the older MINIs just fine. 15x7 rims often weigh about 12-13 pounds, some less. 14" wheels don't fit over the stock brakes.

16" wheels often weigh about 13 to 17 lbs each. Weights can vary and forged wheels are lighter and strong. Gravity cast wheels are less expensive and usually heavier.

17" also a standard size for many MINIs probably better suited for those that have MCS vs lower powered MC or cabrio. Tires will be stiffer and lower sidewalls usually 40 or 45 series. If you want comfort you can still choose a smoother riding tire but usually you'll get a little less handling. 17" wheels vary from 13 to 18 lbs each.

18" looks good but might be a bit oversized for the MINI. Need to lower suspension for best results, about one inch drop and usually wheel weight is more about 20+ lbs is common unless you want to spend more. 215/35-18 or 215/40-18 are common sizes. 35 series sidewall are stiff and easy to damage rims if you have poor roads and many potholes to dodge. 18" wheels are about 17 to 20+ lbs each.

19" wheels are often 20 lbs or more but some can be light (also usually expensive).

Check out the threads below.

 

See

16" wheels-
https://www.northamericanmotoring.co...d.php?t=119917

On heavy vs light weight wheels-
https://www.northamericanmotoring.co...ad.php?t=69678
https://www.northamericanmotoring.co...d.php?t=112422
https://www.northamericanmotoring.co...d.php?t=106099

On larger wheels and ride quality-
https://www.northamericanmotoring.co...d.php?t=100218

On wheel weight and performance-
https://www.northamericanmotoring.co...ad.php?t=95865
https://www.northamericanmotoring.co...ad.php?t=90561

Wheel width and handling-
https://www.northamericanmotoring.co...ad.php?t=51382

and many many more. Just search.

 

There is very little visible difference in 17" vs. 18" wheels IMHOP. (Think about it, there is only a .5 in. increase on each side of the circle.) Strictly a matter of personal preference. 17" usually cost less than the 18" as well.

 

Minihune, many thanks!!

 

The bigger and heavier the wheel and tire, the slower you will accelerate and brake, the ride will get harder, and the adhesion to the road in corners will be less.

The tradeoff is whether you want to Go faster, or just Look faster.

(I've got 9 lb. 7"x15" wheels, which fit fine over Wilwood big brakes)

 

Which wheels are you using, OldRick?

mb

 

Yes, the diameter of a larger wheel will trick the eye a little so one inch larger isn't as big a difference as between a 14" and 15" wheel.

One difference using 18" or larger wheels vs 17" will be in tire size.
It's common to use 40 or 45 series tires with 17" but for 18" or larger usually you can use 35 series tires which have very small sidewalls. Even 40 series looks small.

Another difference is you can also choose different widths. The wider the rim the wider the tire size can be. 17x7 is the most narrow you'll easily find while 18x7 is also common but you can get 17x7.5 or 17x8 and many larger rims come in 8" sizes. Watch the offsets as the wider the rim gets the less offset you want. At the same time you have to keep tire diameter smaller than stock so that the wider tire and wheel will still fit the MINI without rubbing especially in the rear.

A 17x8 rim will be heavier than a 17x7 rim but you can then use for example-
Bridgestone Potenza RE-01R in 235/40-17 made for 8-9.5" wide rims, weighs more at 25 lbs, has tire diameter of 24.4". This will fit and give a very wide look. About a +38mm offset will work. Better handling and cornering and more rolling resistance and lower mpg.

 

I've got SSR Comps, from Tire Rack. They list the weight of their wheels in various sizes. You can find wheels that are substantially lighter than OEM, at much lower cost.

Note: to see 15" wheels that fit the MCS on www.tirerack.com , you have to specify a non-S MINI, or they will only show you 16" and larger...

 

So wait, Minihune, are you saying best to stick with 17" on a MCS Cabrio vs going down to lighter-weight 16s with 205-50's? Given that it's a cab, what's a better choice for mostly aggressive street driving and occasional tracks days: 17s with RE-01 205/45/17 or 16s with Eagle GSD3 205-50-16? See my setup in my sig. Sorry if I misunderstood!

 

MCS can use any size rim and tires from 15" to 19".

Any cabrio will benefit from lighter rims (all sizes).

MCS cabrio is fine with 16" wheels and 205/50-16, a compromise size that is well suited for any MC or MCS, cabrios and clubmans as well.

For any street driving both RE-01R and GSD3 will work fine but GSD3 will last longer.

On the track RE-01R (any size) is superior but both will wear down pretty quickly after a few outings because stock camber is not negative enough in the front to make even use of the tread, outer edges will wear very fast even in one day.

 

Thanks Minihune. I was just thinking you were saying there was some reason why going smaller than 17s would be detrimental on the cabrio - perhaps due to weight or something. Was just making sure!

Installing camber plates next week!

 

Two types of front camber plates to choose from.

Fixed plates- costs less, but you can't adjust camber right to left, you get whatever you get. Better than stock.

Adjustable camber plates- fully adjustable to the point of rubbing some suspension part. Usually you get -2.2 to -2.5 degrees on each side. A small difference like 0.1 degree is not a problem.

More front camber is good for high speed cornering but for daily street driving you can wear the inner edges of the front tires a little more, not a big problem.

Make sure toe setting is not too far toe out. Zero toe is OK or 1/16" toe out can be OK as well. Stock toe setting is toe in. Too much toe out will wear your front tires. A little toe out will help steering response.

 

See 16 vs 17 https://www.northamericanmotoring.co...ad.php?t=80307

also More info
https://www.northamericanmotoring.com...d.php?t=100546
https://www.northamericanmotoring.com...ad.php?t=97047
https://www.northamericanmotoring.com...ad.php?t=80353
https://www.northamericanmotoring.com...ad.php?t=99390