A helpful site to calculate the top speed in a specific gear(s):

http://www.turnzero.com/technical_re...ear_calculator
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Click on Transmissions on the following page to get the Cobalt data:

http://www.chevrolet.com/cobalt/specifications/
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For my SS/SC Final drive ratio = 3.94

Gears 1-5...... 4.05, 2.02, 1.35, 0.98, 0.69

Tire 215/45/18

Max RPM Stock 6500; Stage II 7000rpm

Skip the tire deformation/flex adjustment.

Enjoy!

 

Good find! Those ratios are incorrect, though, despite them being listed on the USA Chevy site. (when will they fix it, anyway?)

The correct numbers are:

1st - 3.38
2nd - 1.76
3rd - 1.18
4th - .89
5th - .70

Reverse - 3.17

Final drive is 4.05

Also, redline is technically 6450 stock, although that will have a minimal effect on the numbers.

On running those numbers, though, the results are interesting. The website is off by about 3% on the fast end. I wonder where the discrepancy comes from?

 

Thanks for the corrected ratios. The tire deformation/flex correction will adjust the numbers about the 3 % you are looking for.

Stage II 7000 rpm max

1st gear: Total gearing in first gear:
Maximum speed in first gear: 13.689
37.7 mph
2nd gear: Total gearing in second gear:
Maximum speed in second gear: 7.128
72.4 mph
3rd gear: Total gearing in third gear:
Maximum speed in third gear: 4.779
108 mph
4th gear: Total gearing in fourth gear:
Maximum speed in fourth gear: 3.6045
143.2 mph
5th gear: Total gearing in fifth gear:
Maximum speed in fifth gear: 2.835
182.1 mph


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For 6450 rpm

1st gear: Total gearing in first gear:
Maximum speed in first gear: 13.689
34.7 mph
2nd gear: Total gearing in second gear:
Maximum speed in second gear: 7.128
66.7 mph
3rd gear: Total gearing in third gear:
Maximum speed in third gear: 4.779
99.5 mph
4th gear: Total gearing in fourth gear:
Maximum speed in fourth gear: 3.6045
132 mph
5th gear: Total gearing in fifth gear:
Maximum speed in fifth gear: 2.835
167.8 mph

Do those results look correct to you?

 

Those numbers are dead on. Thanks for the tip.

So I guess that adjustment figures in the weight of the car pressing down on the tires, effectively reducing the diameter ever-so-slightly?

 

Yep.