Tooth sprocket question...

ueyteuor

New Member
Hi there, I need some advice... I just purchased a grubee 66/80cc starfire kit... though i do not know how many teeth the sprocket it includes has...

Anyhow, what I am wondering is what type of sprocket tooth count would be right for my bicycle? Bicycle wheel is 20"!! So this is why I am wondering, since I don't see many motorized bicycle with only 20" wheels...

Another concern is that where I live there are many hills... which sprocket would be best for pedal-helped hills, and with the fastest speed, on 20" wheels...

Thank you!
 
Probebly a 40 to 44 tooth came with it,,,,that on a 20 inch wheel would possibly be able to climb trees,I don't know if they make a gear ,for 20 inch wheels,that would need pedaling help on hills,I'm thinking the smallest is 36 teeth.someone may know of others
 
the smaller the wheel, the quicker the acceleration. you can get away with a smaller gear than the average 26" bike has. in theory, you'll need a smaller sprocket to get up to top speed, compared to a bigger wheel.

like, if a 26" had a 46 tooth, you'd need a 36 to keep up (i'm just guessing, i'm sure there's an equation somewhere that'll tell you actual wheel diameter + sprocket size = speed..)

there's people that claim a smaller bike won't be able to keep up with a larger wheeled bike at top speed, but in the real world, they're wrong.

with a 20", you could run a 30, or even a 28 and still climb hills, as long as your engine is tuned right.

i have a 24" with a 30 tooth, and i've run 30mph+ up 6% grades.
 
i have a question my scwhinn has a 24'' front and a 20'' back tire i have a stock gear on mine should i upgrade to a lower tooth gear?
 
62.83 inches per turn on a 20 inch wheel/
81.68 inches per turn on a 26 inch wheel/
about 25% less travel
40 tooth divided by 4 =10, x 3 =30 tooth ?
 
75.4 inches travel on a 24 inch tire
12.96% shorter than 26 inch wh.travel
about 1/8 difference
40 tooth divide by 8 = 5,x 7 =35 tooth ?
 
27 would be for more speed on the flat lands ,and less power on the hills,your weight will play a part,100-145 pounds 27 tooth,above that I would do the 30 tooth(or more w/cargo being carried),,,,,simi trucks dont hold 65 mph on hills and gear down (same as putting a larger gear on their rear axle) to climb the hills and use the power their engine has w/out boging down, slower speed "but works",,,,,,,,,,,,,
 
Thanks! So I guess I should settle for 27t, I am a light person...

Do you know where I can get a 27t that's a direct fit? If not I would probably just have to find a 27t and have the mounting holes made custom...
 
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