Best rear sprocket size

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5-7HEAVEN

Well-Known Member
Aug 2, 2008
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Well, I'm not referring to clay.

And I'm done dissing The Night Rider.

clay, did you tighten up your engine chain?
 

xXNightRiderXx

Active Member
Jan 12, 2017
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Eh. I don't generally speak in generalizations, only when I'm tired or bored. If I did speak in generalizations, its because I was tired. It takes less brain power. Which right now I need for gear ratios and such.
 

xXNightRiderXx

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Jan 12, 2017
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How did that 36 tooth run for you? I'm about to put a 36 on a triple 40 zeda I have a 44 and the wheel I'm using is a 700c so a 36 on 700c would be like a 40 on a 26 I think
I think a 36t on a 700c would be more like a 30 on a 26, because the 700c is basically a 28" wheel. However, the difference in resistance due to size I'm sure is minimal. Its your tire width, tread style, and air pressure that affects the rolling resistance. An aggressive tread will offer you more traction in conditions that would make a smooth wheel hazardous, at the cost of efficiency. A smooth tread will offer you better grip in optimal conditions at the cost of shock absorption, and is preferred for street uses because of the lower rolling resistance. Also, a smaller tire at higher pressures will offer better efficiency over a larger tire at lower pressures, and vice versa. My mongoose is holding a 79cc pred, and uses off road tires at around 40psi because the higher pressures allow me to get moving easier. Of course I may have lubed my clutch too much and I'm having issues with the chain, but its all in the name of learning.

P.S. 79cc preds do not put out more than 1.5 volts ac, so get an alternator for any lights you decide to put on them.
 
Jan 21, 2015
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Portland, Oregon
In my experience there is a significant difference in resistance due to size when comparing the 700c to a 26". I used to have a 700c road bike with a 79cc predator at 13:1 gear ratio, now I have a 26" mountain bike with fat tires, also at 13:1 ratio, and the mountain bike beats the road bike in both top speed and acceleration ability.
 

xXNightRiderXx

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Jan 12, 2017
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Now, you're saying that you took the equipment off the road bike and put it on the mountain bike? Or did you make a whole new build but use the same parts? If everything was kept proportional to the wheel size, then there would be very little difference. Also keep in mind that a 26 inch has to roll faster than a 700c to make the same speeds.
 

curtisfox

Well-Known Member
Dec 29, 2008
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Now, you're saying that you took the equipment off the road bike and put it on the mountain bike? Or did you make a whole new build but use the same parts? If everything was kept proportional to the wheel size, then there would be very little difference. Also keep in mind that a 26 inch has to roll faster than a 700c to make the same speeds.
NR is right the 700 should of had a bigger sprocket, you were over working the engines tourqe. 700 is same as 28" , and would be harder to turn..................Curt
 

hogue676

New Member
Oct 7, 2020
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I want to put a smaller sprocket on my bike as well but I'm changing bikes I'm taking the motor I have and putting it on a different frame because the frame that I have now has 27 and a half inch tires and somehow they got warped or the back one did now I'm taking it off of my frame that I have and putting it on a trek 6500 with disc brakes and all that I'm fixing to order a 36 tooth sprocket what I would like to know is will it hook up with the same bolts and grommet and back plate as I have already? I'm going to post pictures of both bikes the next question I have is how will a multi-year bike work with the 80cc motor y'all please let me know tell me what I need to do I'm learning as I go I have done oodles and oodles of reading so I'm learning but I need some people that know what they're doing appreciate it y'all
 

hogue676

New Member
Oct 7, 2020
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I want to put a smaller sprocket on my bike as well but I'm changing bikes I'm taking the motor I have and putting it on a different frame because the frame that I have now has 27 and a half inch tires and somehow they got warped or the back one did now I'm taking it off of my frame that I have and putting it on a trek 6500 with disc brakes and all that I'm fixing to order a 36 tooth sprocket what I would like to know is will it hook up with the same bolts and grommet and back plate as I have already? I'm going to post pictures of both bikes the next question I have is how will a multi-year bike work with the 80cc motor y'all please let me know tell me what I need to do I'm learning as I go I have done oodles and oodles of reading so I'm learning but I need some people that know what they're doing appreciate it y'all
 

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GarrettV719

New Member
Oct 18, 2020
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I suggest a 40 tooth sprocket, any smaller than that your engine won't have enough torque for good acceleration.