How do translate rpm into mph??
12-13-2002, 02:36 PM
#4
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This is what I tried and it didn't come out right
3000 rpm in first gear, ratio is 3.24
3000 rpm* 60min/hr * 1/ratio = x revs @ wheel/hour
x * 76 inch/rev * 1/12 foot/inch * 1/5280 mile/foot.
So for 3000 rpm in first, wheel speed should be 66.6 mph which does not make sense, Any thoughts??
3000 rpm* 60min/hr * 1/ratio = x revs @ wheel/hour
x * 76 inch/rev * 1/12 foot/inch * 1/5280 mile/foot.
So for 3000 rpm in first, wheel speed should be 66.6 mph which does not make sense, Any thoughts??
12-13-2002, 03:40 PM
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Yes, this is how...
You left out a lot.
Divide by the transmission gear, then final gear, then multiply the outside circumference of the tire (225/45 x 17 = 78.5in) to tell you how far you will move a minute. Then just use some quick in->ft->mile and minute->hour conversion factors.
3000rpm in first gear:
3000 * 1/3.5 * 1/4.111 = 208.5 RPM @ the wheels
208.5 * 78.5 in = 16367.23 in/min
16367.23 in/min = 1365.93 ft/min
1365.93 ft/min = 81955.8 ft/hr
81955.8 ft/hr = 15.52 mph
3000rpm in sixth gear:
3000 * 1/0.684 * 1/4.111 = 1066.89 RPM @ the wheels
1066.89 * 78.5 in = 83750.48 in/min
83750.48 in/min = 79.30 mph
Divide by the transmission gear, then final gear, then multiply the outside circumference of the tire (225/45 x 17 = 78.5in) to tell you how far you will move a minute. Then just use some quick in->ft->mile and minute->hour conversion factors.
3000rpm in first gear:
3000 * 1/3.5 * 1/4.111 = 208.5 RPM @ the wheels
208.5 * 78.5 in = 16367.23 in/min
16367.23 in/min = 1365.93 ft/min
1365.93 ft/min = 81955.8 ft/hr
81955.8 ft/hr = 15.52 mph
3000rpm in sixth gear:
3000 * 1/0.684 * 1/4.111 = 1066.89 RPM @ the wheels
1066.89 * 78.5 in = 83750.48 in/min
83750.48 in/min = 79.30 mph
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