Originally Posted by
kung fu jesus
I ran 225/45-15 on 7.5" wheels.
Just a few additional thoughts on your choices...
The 225 adds a LOT of additional lateral grip, but that sizing is limited and prone to running out of stock. The 205 is a far more widely available size. On an 8" wheel, most 205s sit square on the wheel, a few look a tad stretched, but depends on the manufacturer and if the tire has a rim protector. Not all 205 width tires are the same size, as you probably already know.
Another interesting bit on the 205 vs 225 sizing is you have to consider the contact patch. These patches are basically oval. Oval have a long and short axis. The long axis is across the width of the tire, the short is parallel to the direction the car is headed. With a wider tire, the contact patch oval is wider, but the short axis is even shorter than a narrower tire. Where this becomes important is when water or rain is involved. I found in the rare occasion that I drove on my 225's while living in SOCAL that it rained, the car was far more likely to hydroplane than on the narrower tires. My 225s were RS3s, the other tires (195/60-14) were Falken 615Ks.
Also, what you gain in lateral grip on a 225, you lose in feel or agility, even slip angles. This is a subjective portion of the decision, but to me, with the 225s, they were great when I wanted shear grip, but the steering felt much heavier and the slip angles were changed beyond what I preferred. It was sort of boring, not as lively.
I think that for the additional grip a 225 may add, a stickier 205 can achieve, can be found more readily, and the steering still feels like a Miata. To that end, a 195 or 185 is a hoot under similar circumstances, but it just requires a bit more work and attention.