Gearage ratios.. RPM speed.... Im lost...

[forestbrian88]

ok i went testing my top speed with my GPS... endend up with a 100km/h top speed
stock 15 / 38
20 inches tire

i had notthing to do so i decide to calculate my engines RPM at that speed to see if i was near or far from the red line..(9300)

i ended up calculating 2647 RPM in 5th gear, at 100km/h
is this correct? or am i in the ditch??

if im correct then my calculation would let me ride 100km/h in 1st gear at 7720RPM ?
im good in math but im sure i missed something in my calculation... or i just dont get it lol

[beastlywarrior]

Did you factor in the gear ratios of the transmission

[forestbrian88]

i had everything in just figured out what was the mistake
there is 3 ratio to consider:

Sprokets (final drive)
Transmission (gear)
Clutch to crank (primary drive)

i had forgotten to calculate the primary drive so it was only giving me the actual Clutch basket RPM instead of the Crank RPM

so im turning at 7476RPM with 20" tires with stock sprokets doing 100KM/H (60MPH)
im saving these info on Exel on a spreadsheet to help me out to play with sprokets size