I'm considering a tire/wheel combination that is 1.2" in diameter larger and 14 lbs heavier (31.3"/78 lbs) than my current set (30.1"/64 lbs). Does anyone feel that there will be a noticeable reduction in acceleration?

 

I did about the same thing you're talking about. Mine aren't heavier but the size change is the exact same. I did notice a little drop in acceleration because it raises your overall gearing a little, but the new tires/wheels hook a lot better now so I get traction quicker. My highway gas mileage also went up a tad too.

 

What kind of tire/wheel combination do you have currently and what are you considering? I'm curious because tire/wheel weight is important to me. Anyways, you will see a decrease in acceleration performance due to the increase in tire diameter and wheel weight. The increase in tire diameter changes your overall gear ratio, like StrokerAce03 said, and the wheel weight adds unsprung weight which also slows acceleration/increases braking distance. I'm guessing your 1/4 mile time would increase about 3 tenths, depending on the new wheel size.

 

there all right the taller or heavier the more it hurts you

 

Sorry...took me a while to find my post after it got moved.
My current set is the Silverado LS chrome 16' wheels with the optional-sized General 255/70/16 tires...size and weight as stated. I was considering an Eagle Alloy 18/Michelin 285/60/18 also with size/weight as stated. The diameter difference is 1.2 inches and the weight difference is 14 lbs. My rear end is a 3.73.

 

I am running Eagle Series 114 with 285/60-18 Yokohama tires. I started out with the Michelins but they did not hold up well. The Yokos have equal if not better performance with a better price.

No reduction in performance for me but I have a little extra power to drive them.