Does anybody know the ratio of the primary drive in the Blaster? If not, does anybody have one apart that could count the teeth on each gear for me? I'd like it for some calculations. I'm thinking it must be in the range of 2.5:1 or so??
Acording to my manual the primary reduction ratio is 3.227
Do know... thats what my manual says. Maybe thats the trans reduction?
For those of you stumped, I was looking for the reduction from the crank to the trans input shaft. I'm calculating theoretical top speeds with different final drives and tire sizes at 8500 RPM
So then, with stock gears and 20" tires, the calculation goes like this.
1) 20"x 3.14 = 62.8" circumference / 12" = 5.23 ft per tire revolution
2) 8500 rpm / 3.227 / .905 / 3.08 x 60 mins x 5.23 ft / 5280 ft/mile = 56.16 mph. Not too impressive but it is a way to figure out what gearing/tire size you need for your target mph. Not a big deal for me, as I'm usually in 3rd-5th gear max on the trails. But interesting anyway.
Circumferences for various tire sizes (assuming published size is close to actual size, not always a safe assumption)
18" - 56.52"
20" - 62.8"
22" - 69.08"
Gear ratios for various combinations:
13/40 = 3.08
13/39 = 3.00
14/38 = 2.71
etc, etc, etc
So a 22" tire with 14/38 gearing, assuming enough motor to pull 8500 rpm would have a theoretical top speed of about 70.1 mph. Pretty good improvement over stock.
Yes, I'm bored...
o that doesn't take that long lol. just simple math. pretty cool that you're taking some time to do that....
Thanks, this helps clear up a big issue for me. Rep points, simple math, but good info.
Then also gotta take into effect frictional forces and aerodynamics. (j/k)