gearing ratio spreadsheet

[reagor]

hope this helps some of you out

i plotted out the differant gearing options for blasters

idk what the limits aer so i went a few up and down from stock on both gears

the top number is the rear(axle) sprocket and the side numer is the front(motor) sprocket

ok so i forgot about the primary drive, and i dont want to redo all the mathz
here is a link provided by our friend quadrider10 that takes all the thought out of it

http://www.celicatech.com/luni/gearingcalculator.html

****disregard below*****


hopefully this will help other compensate for the changes in tire size on the rear


tire circumferance is pi*D

tire size - circ (in) - circ(ft) - circ(mi)

18 - 56.52 - 4.71
19 - 59.66 - 4.97
20 - 62.80 - 5.23
21 - 65.94 - 5.49
22 - 69.08 - 5.75

gear ratios
1st 3.091:1
2nd 2.214:1
3rd 1.667:1
4th 1.250:1
5th 1.056:1
6th .905:1

and now for the new mathz you wrench monkeys

now you can ((rpm/ratio/gear*circFT)*60)/5280 to get your speed at a given rpm

the max rpm of a blaster IIRC is 10,500

so 10,500[theoretical redline]/3.08[stock 13/40]/.905[6th gear]*5.75ft[22in tire] = {168289fpm * 60)/5280 = 246mph

now this is obviously wayyy unlikely but you would have to redline 6th for that to happen

air drag, hp, weight etc are not factored into this equation

lets say 3rd gear 22in tires stock gearing theoretical redline

((10,500/3.08/1.667*5.75)*60)/5280 = 133mph

again unlikely so what is a realistic redline

lets say 6k in 1st gear

((6000/3.08/3.091*5.75)*60)/5280 = 41mph

somewhere in here my math is off theres no way you can do 41mph in first

if you lifted the rear off the floor and pegged it in the shop this might be possable

maybe its the redline? does anyone know the realistic redline of a stock blaster?

someone help fill in my gaps as this would make a great sticky

lets try some reverse math
a stock blaster top speed is 58mph

58*5280/60 = 5104fpm / 4.71ft[18inch tire] = 1083.65[axle rpm] *3.08*.905[6th] =3020rpm

lets use that

3020 redline stock gears 22" tires

((3020/3.08/.905*5.75)*60)/5280 = 70mph

now we're getting some where lets play with gears now lets go down a tooth to a 12 on the front

((3020/3.33/.905*5.75)*60)/5280 = 65mph

almost there lets go up 1 in the back now 12/41

((3020/3.41/.905*5.75)*60)/5280 = 63mph

12/42 3.50

((3020/3.50/.905*5.75)*60)/5280 = 62.3mph

12/44

((3020/3.67/.905*5.75)*60)/5280

also lets move some sh*t around so its easier
3020/.905*5.75*60/5280=218.04 /3.67 == 59.41mph
so to have the same speed at the same rpm as stock but with 22in tires you would need to run 12/44 gears

this is theory in the real world on modified bikes with differant power bands all this will change

 

[Blaaster]

Great job,

Would you be able to also incorporate tyre sizes and expected speeds, to help the mathmatically challenged choose a ratio to suit their tyre choice.

 

[Quadrider10]

GOOD JOB! adding tire sizes and maybe the estimated speed in there would be Very usefull to a lot of people! rep for you!

 

[borednstreched]

x3 im super lazy and dont want to do the math lol. sticky!!

 

[Rich]

I like your calculator blaaner that is a usefull tool.Should add that here as well.I think the highest you can go on front sprocket is 14.

 

[reagor]

i edited the main post with tire circumferance and gear ratios and some examples

 

[Quadrider10]

nice man GL!!!! here try this out:

http://www.celicatech.com/luni/gearingcalculator.html

for that, all u have ot do its imput the tire size and sprocket size to find ratio and mph.

 

[reagor]

nice man GL!!!! here try this out:

Gearing Calculator

for that, all u have ot do its imput the tire size and sprocket size to find ratio and mph.

ahhh the primary chain ratio i forgot about that
thank you sir i knew i was missing something

 

[79 bronco]

Nice!!!!!!!!!!!!

 

[Quadrider10]

Lol that would do haha

 

[Rich]

Nice!!!!!!!!!!!!

Sorry out of topic but that is one nice build broncoI:IHard to believe thats a blaster.Looks like an all around joy to ride.