Quote:
Originally Posted by moonmonkey
the extra unsprung weight would have less of a negitive effect if you drive alot of highway, but stop and go could hurt because accelerating the extra mass is the biggest problem not maintaining it, heavier rims once rolling have a flywheel effect that helps cancel out the extra rotating mass (but lighter is always better),, what were the height/gear ratio differances between the two tires?
|
On byways I did notice a 2-4 mpg loss of FE using the 32 lb heavier tire/rim set. The 155/80/13s are supposed to be 22.8" in diameter while the 195/50/15s were supposed to be 22.7....the 15s and both sets of the 13s when checked using mile markers on the interstate (which can be off, but I checked out a 200 mile distance that is dead on) show 100.7 miles in a 100 mile distance. The 15s should have been 2/10ths of a % off but all three sets are off by 7/10ths of a %. At the dragstrip (the day this pic was shot) the heavier set of 15s slowed the car down from 19.9s to 20.6s and I had tp pack it up and go home since most tracks require that you run under 20 seconds in the 1/4. I took it out to test and tune and ran the same 19.84 repeatedly where as it was done only once in the past, you need to remember that the car is now lighter by 40 lbs AND instead of shifting at my usual 5700 I shifted at 5400. It should run in the 19.6 range by shifting later and not using 4th at the mph lights...60 feet from the finish line. The car coasts even better now with more modern 13s compatred to the PO craps that were on it.