motorized bicycle 44 to 36 tooth sprocket swap

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Nikko

New Member
Jun 23, 2011
138
0
0
So Cal
has anyone gone from a 44 tooth rear sprocket to a 32 ? i ordered a 32t and want pure top speed. do you guys think my engine will get me up there its an 80cc and i dont mind pedaling till i get to speed, does anyone know how fast ill be going with a 32 in the rear?
 

Saddletramp1200

Custom MB Buiilder
May 7, 2008
1,451
83
48
Houston, Texas
You pick up about 8-10 mph. Depends if you believe your speedo or not. I have passed cars in a 40 mph zone. My Cat's Eye was showing 37 mph. Bikers never lie about their bikes so I would guess it would go around 40. + or -. My Sun 29" did 122 mph one night :) In the back of a Chevy SS Pickup. I was not riding it at the time, rotfl
 

ducedave

Member
Apr 17, 2011
370
4
18
Mentone Ca.
I go 35ish + with a 44t. I'm going to get a 40t soon, the bike climes good with the stock gear but at the races at Willow springs a skinnier rider who pedaled with a strip down bike and a 36t was on me close enough to make me pedal too. so I think a little more top speed would be good at the races this Oct. in Apple Valley with the longer track. A 36t I fear there wouldn't be enough grunt out of the corners taller pedal crank gear would be good so I could assist the motor past 14mph which is all I'm good for with the low cruiser bike gears it has now.
Speed is good for the track flat ground and traffic--- BUT UP GRADE YOUR BRAKES AND KEEP UP YOUR MAINTENANCE!!!---I've tapped grease zerts into my hubs- so I don't have to mess with chain alinement and springer forks to lube the bearings just pump full and wipe clean and I added a V brake in the rear and I'm having a front drum brake off a moped drilled out for 36 spoke holes.
 
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Kristof

New Member
Jan 21, 2011
232
0
0
Aliso Viejo, CA
I have a RAW 80cc and 700cc tires. I am looking for a 40 tooth, anyone know where to get one?

I dont want to go 36, because i have some steep hills around here, but once i get away from the hills...it really sucks going straight at wot. Very annoying and too much revs for the engine, i want it to last.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Andy at Kings Sales & Service has a listing on ebay that offers a 39 tooth here is the link.
Bicycle Engine motorized bike 27 to 39 Tooth sprockets | eBay

Or better yet just go to Andy's add link here on the forum (Kings Sales & Service) it's the 6th add from the top on the right side of this page.

I have one of his plain Alum. 34T sprockets on one of my bikes and it is a great sprocket and works perfect with the rag joint coupler set up.

Aluminum Sprockets | King Sales and Service

Peace, map
 

Kristof

New Member
Jan 21, 2011
232
0
0
Aliso Viejo, CA
So, how much torque will I loose with a 36 or 40?

I wouldnt mind pedal assisting uphill.

How fast would i need to get going in order to engage the engine? I need to know, because there are steep hills around my area.
 

Nikko

New Member
Jun 23, 2011
138
0
0
So Cal
i had a 32 tooth for a while before i upgraded to the Shift Kit, and i had to maybe pedal to about 8 miles an hr i would assume and then i would be fine, so maybe across the intersection then your good.
 

Nikko

New Member
Jun 23, 2011
138
0
0
So Cal
holy crap 81 tooth sprockets? i wanna see someone riding with that. thats probably capable of burning out
 

retromike3

New Member
Jan 9, 2009
148
0
0
Beaverton OR
I have a 36 and it works grate for what I need it for. According to this speed trap sign near my house I was getting close to 40 miles an hour with my 36. Since at the time I didn't have my tachometer I wasn't sure how far I was winding out.

The main thing that I got with the 36 was the ability to climb fairly steep hills. Now I still had to do some pedaling, but that's not necessarily a bad thing.I thought about getting a 32 but I don't think my little engine has quite the power to push my ride iany faster. I will note that the main thing that slows people down is not the gearing but the wind they have to push out of the way. If you can get your body positioned lower and longer you will go faster.

mike
 

ducedave

Member
Apr 17, 2011
370
4
18
Mentone Ca.
So, how much torque will I loose with a 36 or 40?

I wouldnt mind pedal assisting uphill.

How fast would i need to get going in order to engage the engine? I need to know, because there are steep hills around my area.
go down hill to start turn and go where you wont
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
So, how much torque will I loose with a 36 or 40?

I wouldnt mind pedal assisting uphill.

How fast would i need to get going in order to engage the engine? I need to know, because there are steep hills around my area.
I have one bike that has a 41T on it and it also does very good on the hills only issue I have with the 41T is that it is only comfortable to ride at 25-27MPH above 27MPH the vibes get uncomfortable with my engine.

With my other bikes that have the 34T and the 36T I can cruise real comfortably @ 30-32MPH and top out 38+MPH for a short distance.

Very steep long hills will take away from the speed pretty quick with a completely stock engine and exhaust, If you're a lite weight 150lb or less it wont be as bad as with someone like myself that weighs 200lbs.

Question: Do you have a upgraded exhaust? (Expansion Chamber) or Homeade Unrestricted set up?

Is the carb. rejetted and tuned well?


These 2 things will make a big difference in what you can get away with on the sprocket size.

I'd say if the Hills around you are very steep and long and you have some mods done to the engine, go with the 38T if you dont mind a bit of peddling at the top possibly, or go with the 40T and you will have a bit less peddling probably but you will loose a couple MPH cruising speed as well, 38-40T is probably about the best all around # for most peoples situations, but I like my 36T the best out of all I have.

Peace, map