Outer Limits 4x4 Board

I need the formula to find what RPM I'll have with a certain tyre size...

Search found this "RPM = km/h divided by 1.6 x gear ratio x 336 divided by tyre dia.".... What is 1.6 and 336?

My overdrive - 0.696:1 Final ratio - 4.11. I need about 2000RPM @ 100km/hr

Thanks in advance for the formula.

Dave.

Be around 29.9" or 759mm.


RPM = ( Gear ratio x T-case Ratio x Final drive ratio x RPK x SPD)/60

RPK : Tyre revs per km

SPD : Speed in km/h

RPK = (60 x 2000)/(0.696 x 1 x 4.11 x 100)

RPK = 419.5


RPK = 1000000/(Tyre Dia. in mm x 3.142)

Tyre Dia. = 1000000/(419.5 x 3.142)

Tyre Dia. = 759mm or 29.9"


There is also a tyre slippage factor at play which you could also take into account if you wish of around 3%.

this link is pretty helpful as you can quickly look at all gears and the effects at different speeds

http://www.grimmjeeper.com/gears.html the only downside is you need to convert from mph to kph but I am sure your capable of that