19" vs. 18" Wheels/Tires

[BYprodriver]

Originally Posted by Johnny Danger

I disagree with you assertion . Ultimately, it comes to reducing unsprung weight and rotational mass. If the overall circumference is consistent, regardless of diameter the the lighter wheel will create less inertia .

What would be the correct assertion if the overall circumference is inconsistent?

[Johnny Danger]

Originally Posted by BYprodriver

What would be the correct assertion if the overall circumference is inconsistent?

Here's an example:

The original factory set-up on my vehicle consisted of 18 inch Sport Design wheels

18 x 7.5 225/40/18
18 x 9 265/35/18

Current wheel set-up

19 x 8 235/35/19
19 x 10 275/30/19

Practically speaking, the overall circumference of the wheel and tire combination is similar (had I kept the fronts at 225 and the rears at 265 the circumference would have been virtually the same) . However, I have reduced approximately 60 lbs.+ of unsprung weight and rotational mass ! As far as acceleration, braking and overall handling is concerned, this has proven to be a night and day difference over the oem set-up . And, ride quality has not suffered one bit.