Don't want to be nitpicking, but a light flywheel can't entirely be compared to a light wheel. The acceleration gains of a light wheel is independent from the selected gear, the wheel speed is usually the same as the actual speed of the vehicle. The acceleration gains of a light flywheel on the other hand is not independent from the selected gear (it's as you mentioned most noticeable in the lower gears).

 

Addtional information. He also did a comparison between rx7 FD rims (16x8) and the Rx8 rims (18x8) between two runs on the drag strip.

With the Rx8 rims [48 lbs] (225/45/18 Stock rubber) he ran a 17.2 in the 1/4 (6i ATX)
With the FD Rx7 rims [34 lbs] (225/50/16 Toyo Trampios (old tire)) he ran a 16.690 in the 1/4 (6i ATX).

Because this was an ATX, its a bit easier to see some consistency between runs. So there ya go, thats about 70 cases of evidence for lightweight tires/rims, with everything from braking performance, to handling, to acceleration benefits in 0-60, 1/4 mile, and track times.

 

Great info crossbow! Thanks for posting these, they are ALL very interesting reading.

 

Otaking posted his time slips with a detailed explanation of the testing for those interested. (The 1/4 mile times with rx8 18's (stock rubber), and FD rx7 16 rims).

http://forum.mazda6tech.com/viewtopi...762&highlight=

Whats most interesting about this comparison...is that the rx8 rubber has far superior grip to the tires on the FD rims.

 

the tire diameters are different - thus effecting the gear ratios and giving better performance.

 

Of course...but 0.5 seconds in the 1/4 is a lifetime. I'd agree with you if the difference was only a tenth....but the overall diameter difference is only 4.3%...which points out that a large % of the gain is from the substaintal loss in unsprung weight.

Even if you said 0.3 of the seconds was from gearing, and 0.2 was from the wheel weight...thats still a rediculous amount.

0.2 in a 1/4 = loss of 200 lbs, or addition of 30 hp in a 3000 lb vehicle.