I'm looking at summer wheels for my Cooper S - Kumho Ecsta 4x on Borbet LV4 rims - but was thinking of moving to 205/50's. I'm pretty certain about switching to that size but wanted to see what others are doing/what others are thinking on this before I drop the cash. I decided to stick with 16's because as much as I enjoy good handling, ride quality is important on the straight and level.

 

Depending on how important the ride quality is, you may want to do 205/55. It is not much, but that extra little bit of sidewall will help.

 

205/55 doesn't fit too well if you're lowered more than ~1", ask me about my popped-off wheel arch

I run 205/50/16. In theory it may provide marginally more lateral grip, but I'm sure it's negligible if it's there at all. If ride quality is important I'd go with the 195/55. You won't give up anything and you'll have a little extra cushion.

 

I run 205/50-16 because there's more choice in that size. There's even more choice in 205/55-16, but they're a bit big.

 

Swapped my 195/55R16 for 205/50ZR16's when I could not find a decent tire in the OEM Tire Size, really depends on what kind of tire you are looking for, I was looking for a long wearing All-Season, I did not want to replace my Bridgestone Potenza G019 Grids with the same tire, wanted a better wet handling tire, the PNW Winters are so unpredictable.

 

Either way you go, please look into those new Bridgestone Potenza RE-11A's summer tires. They are supposed to be an awesome tire and they reduced the price over the out going 11's.