Tire sizing--tread width vs. rim width

This is a really good point from a couple of aspects.

You guys are trying to figure out how to have a faster car, get more grip. But if you can accelerate out of a corner faster that has some benefits of its own.

So by going to the wider tire (better grip = faster through the corners), you are going to add rotation mass to your wheels. The rule of thumb is wheel weight changes are equal to 10x body weight (i think thats the factor). so if you have 4 lbs more in each tire, that's 160 lbs of body weight you would have to remove to have the car accelerate like it did before. or if you go with the 205/45, you effectively drop 80lbs body weight.

But the outer diameter will also affect how your car accelerates. If you have a bigger tire, your car will have a higher top speed, but will also accelerate slower (for the same engine/ gearing). Conversely a smaller tire will allow the car to accelerate faster. Most Lemons cars, and Lemons tracks are not high speed limited, meaning you will never hit top speed in your top gear. So you can give some of that up. if you go with the smaller diameter tire you will loose top speed, but you will gain acceleration, from the smaller diameter, and from the lower weight. all of that will probably make up or over come the benefit from the "higher" cornering speed you would get from the bigger tire. But that is going to be offset by the size and handling of your car. So its kind of a crap shoot.

But the only way to really know this is to test it. Get two sets of the same wheels. mount the =225/50s on one set and the 205/45s on the other. Then drive each for 1 hour, same driver. record lap times and see which one is faster.