Changing 44T up or down

mkatt4x4 · Jan 17, 2014

I have chucked my electric bike idea (1kw=1.34hp), for a gasser, rear rack setup. I think something around 50cc or the 66cc range (5-6HP) will be good.

Now what happens when you change up the 44T sprocket?

The reason I ask is the bike + me = 340 lbs.

Edit: What about switching up the tire diameter from 26" to a lower diameter or 29"

maniac57 · Jan 17, 2014

Smaller sprocket = more speed, less hillclimbing torque.
Smaller wheel is just the opposite. A 29'' will be faster than a 26" with the same gearing.
I'm 250+ and I run a 36 on my 66cc in frame two stroke.
The inframe ratios are a 4:1 primary reduction in the engine running to 10 tooth engine sprocket to 36 tooth rear sprocket.
Not sure what your rack mount engine ratio is.

El_Renzo · Jan 18, 2014

Depends on where u live.if u live in stop and go traffic or dont like to pedal,go with 40 tooth sprocket. If u can top ur bike out on a long straight away and dont mind pedalling a bit,go with 36 tooth sprocket

mkatt4x4 · Jan 18, 2014

I will be getting this kit
GRUBEE SkyHawk GT5A 66cc Angle Fire Slant Head Bike Motor Kit - $170'ish with free shipping. I switched my 42 front Octalink crank to a 48-32-22 and the 11-32 rear. All in anticipation of going electric. But I am going gas now.

How much of an advantage is there in having a Jackshaft for ~$200 and is it worth getting. Like whats the difference between a regualr setup and a Jackshaft setup in terms of different top speeds and hill climbing ability.

I have heard some good comments about Grubee, plus its free shipping, is this a good first motorized bicycle engine kit.

max350 · Jan 18, 2014

mkatt4x4 said:
I will be getting this kit
GRUBEE SkyHawk GT5A 66cc Angle Fire Slant Head Bike Motor Kit - $170'ish with free shipping. I switched my 42 front Octalink crank to a 48-32-22 and the 11-32 rear. All in anticipation of going electric. But I am going gas now.

How much of an advantage is there in having a Jackshaft for ~$200 and is it worth getting. Like whats the difference between a regualr setup and a Jackshaft setup in terms of different top speeds and hill climbing ability.

I have heard some good comments about Grubee, plus its free shipping, is this a good first motorized bicycle engine kit.

Hello! The advantage of a jackshaftkit is that you have both strength and speed
(as a note: there is no 66cc china engine as standard with a 5-6hp)

wheelbender6 · Jan 18, 2014

I went to a 39T. It made everything smoother at cruising speed (25mph or so). The trade off was that I had to pedal a little longer to get moving from stops. I live in a flat area so I don't really know how climbing performance is affected.

rustycase · Jan 18, 2014

4x4, that grubee is probably as good as most of the rest...
still not gonna see the 5hp though
Try it the way it comes out of the box and see how it works for you before concern about mods and improvements
best
rc

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Changing 44T up or down

mkatt4x4

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maniac57

Old, Fat, and still faster than you

El_Renzo

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mkatt4x4

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max350

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wheelbender6

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rustycase

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