craZee Posted December 12, 2011 Report Share Posted December 12, 2011 So who can show me the calculation to find out how fast my car is going with an engine RPM of 5,500 a final transmission drive of 0.864, a 4:38 ring and pinion and a tire diameter of 23.2 inches? Steve Quote Link to comment
datsunaholic Posted December 12, 2011 Report Share Posted December 12, 2011 http://wahiduddin.net/calc/calc_speed_rpm.htm Quote Link to comment
Laecaon Posted December 12, 2011 Report Share Posted December 12, 2011 100.3mph Quote Link to comment
Laecaon Posted December 12, 2011 Report Share Posted December 12, 2011 http://wahiduddin.net/calc/calc_speed_rpm.htm I just used that. lol Quote Link to comment
datzenmike Posted December 12, 2011 Report Share Posted December 12, 2011 I have my own and get 100.466 (close enough) Quote Link to comment
datsunaholic Posted December 12, 2011 Report Share Posted December 12, 2011 Which is Engine RPM divided by Transmission Ratio divided by Final Drive Ratio, x tire circumference (tire circumference is Diameter x π) x 60 divided by 63360. Quote Link to comment
craZee Posted December 12, 2011 Author Report Share Posted December 12, 2011 Thanks to all ! Quote Link to comment
HRH Posted December 12, 2011 Report Share Posted December 12, 2011 Okay, dumb question, how come when I put those numbers in, I get 200.6? Quote Link to comment
datzenmike Posted December 12, 2011 Report Share Posted December 12, 2011 I got the same as you Matt. My calculator says 100.66 Quote Link to comment
Laecaon Posted December 13, 2011 Report Share Posted December 13, 2011 Okay, dumb question, how come when I put those numbers in, I get 200.6? Cuz it says radius, not diameter. 1 Quote Link to comment
datzenmike Posted December 13, 2011 Report Share Posted December 13, 2011 That's the disadvantage of that 'computer'. Tire heights are usually measured and given in inches. Quote Link to comment
Creepy Cruiser Posted December 13, 2011 Report Share Posted December 13, 2011 I just use my GPS, lol. Quote Link to comment
WAGON JON Posted December 13, 2011 Report Share Posted December 13, 2011 I just use Ratsun! Quote Link to comment
DRIVEN Posted December 13, 2011 Report Share Posted December 13, 2011 I know the question is already answered but this is my favorite calculator: http://www.angelfire.com/fl/procrastination/rear.html It lists several results for different ratios if you're trying to find s sweet spot. Quote Link to comment
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