Calculating different differential gear ratios
Stupid question - how can I calculate the effects a different gear ratio has - I know there are things like 3:23, 3:43, 3:73, 4:11 ... and I know that the higher I go, the better the takeoff and the lower the topspeed ... but what are the (mathematical) effects of e.g. going from 3:43 to 4:11?
Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)
What do you mean? How do you adjust your calibration by hand? Or how to project your RPM for a given speed?
At one point in time, I found a bunch of good formulas on Google.
The latter ... effects it will have on the speed (and therefore fuel efficiency) of the car ...
Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)
Garry
Do you mean like this excel spreadsheet on fbodyEurope ?
Roy 98SSSSSS
Tnx Roy!
Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)
Maybe you can improve on it. I usually keep a hard copy in the car due to the limited speedometer to see what top speed I reach by gear and rpm.
Roy 98SSSSSS
You mean this formula...
RPM = MPH * 336 * AxleRatio * TransRatio / TD
where TD = tire diameter in inches
Rearrange if you want MPH from RPM.
Edit: Like this:
MPH = RPM * TD / (336 * AxleRatio * TransRatio)
Last edited by joecar; September 25th, 2006 at 08:27 AM.
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