On 7/19/2017 8:27 AM, Mad Roger wrote:
On Wed, 19 Jul 2017 09:17:21 -0400,
Ed Pawlowski wrote:

You will find some actual test results here
https://www.carthrottle.com/post/how...t-performance/

Thank you for that performance-related test article,
https://www.carthrottle.com/post/how...t-performance/

Where the 3 main performance-related takeaways are...
"the force can be calculated to be around 460 Newtons. Now, increase that
wheel diameter to a set of 19-inch ... Run the calculation through again
and that driving force will decrease to 360 Newtons... which will culminate
in a decrease in acceleration of said wheels."

"Fuel economy will inevitably suffer as well due to the engine having to
work harder to rotate the wheels"

Only if you try to maintain the same acceleration level. Engine and
transmission parts will be moving slower, reducing losses. Only if the
engine ends up at the bad end of it's power curve will the mileage go
down. Some transmissions can be selected for efficiency modes, where
they shift into higher gears earlier. It's the same kind of change.


"Smaller diameter wheels will make for more concise handling as each
rotation of the wheel covers a shorter distance, meaning more acute
adjustments can be made during cornering compared to a larger diameter
tyre"

Really?? The part of the tire that makes ground contact will hardly
change if the width of the tire stays the same. This statement just does
not make sense. What does the rotation distance of the tire have to do
with anything. The smaller tire putting the center of gravity closer to
the ground would make more difference.


To summarize what the article said for moving to larger-diameter wheels...
+ The engine delivers less driving force to the wheel contact patch
+ Which results in a decrease in acceleration & decrease in fuel economy
+ And there will be a decrease in handling (all else being equal)