RPM to MPH Chart

Once upon a time, several years ago, I used the gear ratios, and final drive ratio to work out the true ROM to MPH ratio. (I must have been very bored.) IIRC, it worked out to within a gnats whisker of 25mph/1,000rpm (40kph/1,000rpm). Of course, different tyres will affect this, as will the amount of tread on the tyre and the air pressure - it depends how anal retentive you want to be. On the dyno, at 165mph, this was confirmed.

Therefore true speed at 3,000rpm = 75mph, but indicated speed will be about 81mph.
 
might be 65 might be 125 whatever feels right at the time tach I don't watch very often. bad one to start right now being the state ponters is in right now
 
warp9.9 said:
In Fifth gear
MPH/.0266=RPM
Click to expand...


This formula seems to calculate out pretty well, especially when calculated using some of the information people have provided. I realize tires, tire wear, inflation pressure, a slightly different gear ratios and the like will change the numbers. I was just looking for a sense of how MPH correlated with RPMs on the rocket touring. This all has been very helpful. Interesting how a different Tune could fix the speedo error. It seems stupid to build that much error into the speedometer if it could be corrected by the ECU. Pretty lame thinking from my perspective. I think I'll develop a chart.
 
to my understanding when you put on the larger rear tire it helps to correct speedo but then makes the odometer off.
if some one can just correct the speedo w/o changing miles traveled i would like to know how.
 
Gear Speed Data Entry
Original Equipment Tire Specifications
Tire Width in (mm):
Aspect Ratio:
Rim Diameter in (inch):
Transmission Gear Ratio:
Differential Ratio:
To calculate the speed click the Show Speed button. The results of the calculations appear in the Gear Speed Results.


Gear Speed Results
Engine Speed (RPM) Speed (KP/H) in backets is bridgstone 240/55 16
rpm---------1ST----------2ND-----------3RD----------4TH-----------5TH
8000 ---107-(111)---160-(166)---218-(226)---269-(279)---324-(336)--PONTERS
7000-----93-(97)-----140-(146)---190-(198)---236-(244)---283 (294) ME
6500-----87-(90)-----130-(135)----177-(183)---219-(227)---263 (273) STOCK
1000-----13-(14)------20-(21)-------27-(28)-----34-(35)------40 (42)
 
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