Average Miles per Gallon (MPG)

[Noah49389]

30 miles an hour on a bicycle must be really scary. I'm definitely not a speed demon. I just need a motorized bicycle to help get me up the hills on my town. Besides, there's just not that many places you can simply floor it within the central part of town.

Lugging my lard butt up and down all these hills will really drag down my MPG.

I have tried to find an exact answer but I haven't seemed to have found it - What benefits do a 50 tooth sprocket have over the standard 44 tooth sprocket? Does it offer more pulling power? Does it help the engine not work as hard as it might with a 44 tooth? I am buying an engine in a few days and the engine I chose comes with a 50 tooth sprocket.

50 tooth gives less speed but more power. A 44tooth gives more speed but less power.

 

[jeffuehrer]

30 miles an hour on a bicycle must be really scary. I'm definitely not a speed demon. I just need a motorized bicycle to help get me up the hills on my town. Besides, there's just not that many places you can simply floor it within the central part of town.

Lugging my lard butt up and down all these hills will really drag down my MPG.

I have tried to find an exact answer but I haven't seemed to have found it - What benefits do a 50 tooth sprocket have over the standard 44 tooth sprocket? Does it offer more pulling power? Does it help the engine not work as hard as it might with a 44 tooth? I am buying an engine in a few days and the engine I chose comes with a 50 tooth sprocket.

The more teeth on the sprocket the greater the torque the fewer the teeth the greater the speed.

 

[RobertTheProbable]

I think mpg is derived by average rpm's of the motor on level ground. Obv the more hills you encounter will lower your average mpg, but remember what you burn on going uphill you save on going downhill, not necessarily proportionally though. In any case, a gas bicycle has massively more range than a battery assist bike which in most cases is as little as 20 miles. If you plan on doing 100 mile road trips on a bicycle i hope you invest in a comfy seat, and I would hope you encounter a gas station along the way. You will never have the luxury of having a range estimator on a bike, unless you find a really amazing gps app. If i was ever on a bike for the full duration of a tank of gas, i'd be so drained i wished i was dead. At 269 lbs i think you would be too.

 

[James busse]

Basic geometry the smaller the sprocket the better the torque and and slower the speed

 

[The_Aleman]

Basic geometry the smaller the sprocket the better the torque and and slower the speed

That holds true for a drive sprocket but not for a driven sprocket. Ever rode a bike with a derailleur?

On a typical 2-stroke kit engine, going with a smaller or larger drive sprocket is not an option. The output sprocket is already nearly as small as it can be for the size of the chain, and the engine's casting doesn't give much room to go with a larger sprocket for more speed.

The driven sprocket on the wheel has plenty of room to increase/decrease reduction, however. Smaller wheel sprocket means more speed/less torque; larger sprocket means less speed/more torque. Basic motor-assisted bicycling.

 

[darwin]

On a HS 142f oem tank I can go about 25mi and that is down to about a 1/4 left in the tank. So say about 32mi till empty. The tank is rated at 1.2ltr so 3.75ltr = a gal. So about 96mi per gallon.

 

[Karl Snarl]

well my fav bike had a 66cc 2 stroke, pumping out about 4.5-5HP. totally went all out on it. has custom exhaust , custom intake, custom ported jug, high compression head, a jackshaft with a 6 cog cassette , all on a mountain bike. i have gotten it up to 46mph, then ran out of safe road to run it on. my exhaust is tuned to my intake length and made for torque. i get about 200 mpg out of it if i don't beat the snot out of it. when i beat it, i get around 130-150 mpg. my other bikes in single speed form get around 80-100 mpg give or take, depending on sprocket and how they are ridden.

 

[The_Aleman]

^ 200MPG chinagirl !

On a HS 142f oem tank I can go about 25mi and that is down to about a 1/4 left in the tank. So say about 32mi till empty. The tank is rated at 1.2ltr so 3.75ltr = a gal. So about 96mi per gallon.

I commuted to work on a MPG-tuned 66cc for 2 years, averaged about 75MPG, never got better than 90MPG - and that was with significant pedaling at 25-30MPH with a 34T. For a year I've been playing around with a 48cc 2-stroke, it's on a low-speed (20-25MPH) cargo bike and gets about 80-85MPG without any pedaling help. I've had a shift-kitted HS49 for 10 years, it averages between 110-125MPG at 25-30MPH with cadence-friendly gearing (14.7 cadence per 1K engine revs). I'm just about always pedaling on that bike, crank freewheels will never not make me nervous.

If I didn't pedal at all, I'd prolly get about 95-100MPG.

 

[Karl Snarl]

^ 200MPG chinagirl !



I commuted to work on a MPG-tuned 66cc for 2 years, averaged about 75MPG, never got better than 90MPG - and that was with significant pedaling at 25-30MPH with a 34T. For a year I've been playing around with a 48cc 2-stroke, it's on a low-speed (20-25MPH) cargo bike and gets about 80-85MPG without any pedaling help. I've had a shift-kitted HS49 for 10 years, it averages between 110-125MPG at 25-30MPH with cadence-friendly gearing (14.7 cadence per 1K engine revs). I'm just about always pedaling on that bike, crank freewheels will never not make me nervous.

If I didn't pedal at all, I'd prolly get about 95-100MPG.

pretty sure if you put the time and energy into your engine and build, and then figured out how to ride the most efficient way, you'd get the same. pedaling is involved, no WOT, and lots of pulse driving. half the time the engine is off, the other half it stays at peak torque rpm's. the key is to keep moving, i can ride the bike paths tht run for 100's of miles around here, without stopping. they cut under all major roads, so no need to even worry about lights or traffic. i have traveled 60 miles south to a smaller town, visited people, and rode back home, with gas left for more riding. i have 1 gallon tank on tht bike. don't build for speed, build for torque, then gear it.

 

[The_Aleman]

pretty sure if you put the time and energy into your engine and build, and then figured out how to ride the most efficient way, you'd get the same.

I've been riding these since 2006, check my join date. Was already riding these for nearly a year before I joined. I've used these as my main transportation for over 10 years. Before MaBing I had well over 100K miles chevrolegging, so I'm quite adept at efficient riding. I've been a pedalhead since the early 1980s and a bike mechanic since the late '80s. Just an FYI, before you go mistaking me for a spring chicken here. Don't let my postcount fool you, I'm not an overposter or a double-poster like some guys here.

pedaling is involved, no WOT, and lots of pulse driving. half the time the engine is off, the other half it stays at peak torque rpm's. the key is to keep moving, i can ride the bike paths tht run for 100's of miles around here, without stopping. they cut under all major roads, so no need to even worry about lights or traffic. i have traveled 60 miles south to a smaller town, visited people, and rode back home, with gas left for more riding. i have 1 gallon tank on tht bike. don't build for speed, build for torque, then gear it.

My 4-stroke 5-speed shifter bike is set up for maximum pedal assist, it has a 69.09:1 reduction from engine to pedal crank. In 5th gear at my engine's torque peak - 4500 engine RPM - my cadence is 66RPM and I'm going approximately 25MPH. Built for torque, not speed? Check. Geared nicely? Check. Granted, I'm a fit 6'3" 215lbs, so I'm neither light nor particularly aerodynamic in my 38W36L jeans, but I'm always pedaling on my shifter bike. Due to my gearing work, I have maximum torque from both my legs and engine at same RPM. Never seen better than 125MPG on a trip out of my 1.25 gallon tank (1 gallon usable due to tank angle and anti-slosh stuffing). I'm unable to engage full throttle because I set up a throttle limiter to reduce stress on my bike's drivetrain.

So you have to understand that I find your 200MPG claims a little outlandish. First you say:

pumping out about 4.5-5HP. totally went all out on it. has custom exhaust , custom intake, custom ported jug, high compression head, a jackshaft with a 6 cog cassette , all on a mountain bike. i have gotten it up to 46mph

Then you say:

don't build for speed, build for torque

Umm okay. Nice contradiction there. You have more displacement, twice the power cycles, and claim over twice the horsepower as my 4-stroke, yet you get nearly double the gas mileage of just about anyone truthful I've heard about. So what's your secret?

lots of pulse driving

So...you shut off your engine to coast? Then use distance traveled with engine off as part of your engine's fuel economy claims?

Sounds disingenuous for anything but an automobile. They don't have pedals.

my other bikes in single speed form get around 80-100 mpg give or take

This sounds more accurate. After all, a jackshaft isn't going to double your engine's fuel economy.