Bang gears for less....Multispeed for engine!

[Zomby Builder]

OK

What is the answer? All things considered, The ultimate range for let's say a 100 lb. bike a 200 lb. rider. With a TRUE 4plus HP 4 stroke motor. Direct centrifical clutch with an 8 tooth sprocket. Connect to my jack driver on the left 22 tooth, an 11 tooth reducer on the right. NuVinci with a 22 tooth. Do we do 70 mph yet?

 

[dave1490]

Zomby, gear reduction is an important factor. It helps calculate rpm at mph, and are general theoretical calculations. It becomes more specific when the rider's engine's HP and torque ranges are known.

Total weight, wind resistance, friction losses from all aspects will detract from these mathematical calculations.

They are simply ballpark figures. They show if you're within your engine's power range, or 'way out in left field.

Myron

ya that,s right.if an engine makes peak hp at 6000rpm and makes peak torque at 4500rpm you should gear it for a 1500rpm drop between gears,this way you,ll get the most out of the engine.the closer your number,s come together will tell you if it has a {peaky} or wider {broad} power range.

 

[5-7HEAVEN]

What is the answer? All things considered, The ultimate range for let's say a 100 lb. bike a 200 lb. rider. With a TRUE 4plus HP 4 stroke motor. Direct centrifical clutch with an 8 tooth sprocket. Connect to my jack driver on the left 22 tooth, an 11 tooth reducer on the right. NuVinci with a 22 tooth. Do we do 70 mph yet?

Zomby, it all depends if you're going to use a BRIGGS&STRATTON 4hp engine that peaks at 3600 rpm, or a 4 hp happy time engine that tops out at 7,000rpm.

In other words, ya gear for the engine's range.

for the B&S engine, in low gear top speed is 27.22 mph at 3600 rpm..

in high gear, top speed is 94.7 mph at 3600 rpm, using the gears you've selected.

for a 7,000 rpm engine, in low gear, top speed is 52.9 mph at 7,000 rpm.

Zomby, you will burn out your clutch, and a 12-year-old will outrun your bicycle's engine power.

in high gear, top speed is 184.1 mph at 7,000 rpm.

FWIW, everyone should buy a $5 calculator and use it to estimate sprocket/pulley size, gear reduction, speeds, rpms, etc. It is time and effort-saving, and will help prevent expensive time-consuming trial-and-error experiments.

I use the same calculator in my math class at night school.

Myron

 

[Alaskavan]

Zomby, wind resistance for a standard Mountain Bike = a little better than 10 hp to achieve 70 mph. So, a 4 hp B&S alone won't get you there. You'll need serious aerodynamics.

 

[5-7HEAVEN]

So what kind of engine is ZOMBY going to use with the NuVinci hub?

Myron