Drift trike for the grandbrat!

[Master Hack]

So my 10 year old grand brat brings me his pedal power drift trike. He says granpa my bike is broken, can you fix it? So I puffeds up my chest and said "of course I can fix it! "
The bearings are falling apart from excessive use/abuse, among other problems.
So I did what every good granpa would do... Stripped it down and started planning a electric conversion.

 

[Master Hack]

Trying to figure out the gearing for this thing. 6:1 isn't gonna work cuz the wheels are only 10 inch diameter.
So someone confirm this please, I don't trust my thinkin lately.
10 inch wheel X 3.1416 = 31.1416 inches circumferance.
Motor speed (maximum) 3000RPM
3.5:1 Gear ratio = 857.14RPM (maximum axle speed) (3000/3.5)
31.14 in x 857 MAx RPM = 26,691inches/minute (max)
26,691 inch/min = / 12 = 2,224 Feet/minute x 60 = 133455 feet/hour
133455/5280 = 25.276 MPH

Sound right?

 

[panchothedog]

Math looks correct ( didn't run it out to check for accuracy ), so your thinking is probably better than you are giving yourself credit for. I think the real question is how much torque does the motor make. That is if they even list torque specifications on electric motors.

 

[Denny]

A good grandpa would convert it to gas. 6:1 still works just go down to #35 chain.

 

[Master Hack]

Thanks for the confirmation! You have no idea many times l went over this B4 l started to get comfortable with it!
No tork specs listed, but l'm guessing its big, and instant.

 

[Master Hack]

A good grandpa would convert it to gas. 6:1 still works

Using the same formula:
3600/6 =600 rpm axle speed max
600 x 31.14 = 18684 inch/ min/ 12 = 1557fpm x 60 = 93420 ft/hr /5280= 17.690mph.

you trying to get me fired?

 

[ezcome-ezgo]

No, promoted to Grandpa of the Century.

 

[Denny]

Or at-least grandpa of the week.

 

[Hellion]

The bearings are falling apart from excessive use/abuse....

Well that statement is a sight to behold as well as the process it took to wear it out. He a good boy!

 

[Functional Artist]

Thanks for the confirmation! You have no idea many times l went over this B4 l started to get comfortable with it!
No tork specs listed, but l'm guessing its big, and instant.

48V 1,000W Unite MY-1020 brushed motor specs:

Model: MY1020
Voltage: 48 Volt DC
Output: 1000 Watt
Rated speed:3000RPM
Rated current: 26.7A
Rated Torque: 3.2Nm
Weight 5.25Kg

1Kw power. Ungeared. Suitable for large scooters or bikes and trikes. You would use these in a setup where you wanted to retain the original gearing. Extremely powerful, one of the largest motors Unite makes in a brushed motor.

Trying to figure out the gearing for this thing. 6:1 isn't gonna work cuz the wheels are only 10 inch diameter.
So someone confirm this please, I don't trust my thinkin lately.
10 inch wheel X 3.1416 = 31.1416 inches circumferance.
Motor speed (maximum) 3000RPM
3.5:1 Gear ratio = 857.14RPM (maximum axle speed) (3000/3.5)
31.14 in x 857 MAx RPM = 26,691inches/minute (max)
26,691 inch/min = / 12 = 2,224 Feet/minute x 60 = 133455 feet/hour
133455/5280 = 25.276 MPH

Sound right?

IMO a 3.5:1 GR it too high

FME 6:1 is about ideal
...but, 5:1 is faster

This is how I have been doin' it

Ballpark Equation
MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier(.000189) = Miles Per Hour

If the motor does ~3,000 RPM's
...& were running (for this example, let's say) a 5:1 gear ratio (10T drive sprocket, on the motor & a 50T driven sprocket, on the wheel)
...& (if) the ~10" wheels, have a ~31" cir.

Then, the math would look like:
3,000(RPM)/5(GR) = 500 (axle speed)
500(AS) x 31(TC) = 15,500 (inches per min-traveled)
15,500(IM)/12(FT) = 1,291 (feet per min-traveled)
1,291(FM) x 60(HR) = 77,500 (feet per hour-traveled)
77,500(FH) x .000189(MM) = 14.65 MPH

 

[Denny]

Too much math. Just go gas!

 

[Master Hack]

I need more top end. 14MPH ain't gonna get it. I'm thinkin somewhere around 25MPH would be mo bedder?

 

[Functional Artist]

I need more top end. 14MPH ain't gonna get it. I'm thinkin somewhere around 25MPH would be mo bedder?

Well, here are the "numbers" if ya use a 5:1GR (10T drive & 50T driven)
...with the 10" (~31" cir. wheels)

Ballpark Equation
MS/GR=ASxTC=IM/FT=FMxHR=FHxMM= MPH

Motor Speed/Gear Ratio=Axle Speed x Tire Circumference = Inches per Minute traveled/Foot(12) = Feet per Minute traveled x Hour(60) = Feet per Hour traveled x MPH Multiplier(.000189) = Miles Per Hour

If the motor does ~3,000 RPM's
...& were running (for this example) a 5:1 gear ratio
...& the wheels have a ~31" cir.

Then, the math would look like:
3,000/5 = 600 (axle speed)
600 x 31 = 18,600 (inches per min traveled)
18,600/12 = 1,550 (feet per min traveled)
1,550 x 60 = 93,000 (feet per hour traveled)
93,000 x .000189 = 17.58 MPH

So, accordin' to the "numbers" a 5:1GR would/should produce ~17.5 MPH

IMO almost 20MPH is pretty quick
...when your only ~3" off of the ground
...& a vehicle like that, doesn't provide much protection

How old is this grandbrat?

 

[Functional Artist]

Um...

If the motor does ~3,000 RPM's
...& were running (for this example, let's say) a 5:1 gear ratio (10T drive sprocket, on the motor & a 50T driven sprocket, on the wheel)
...& (if) the ~10" wheels, have a ~31" cir.

Then, the math would look like:
3,000(RPM)/5(GR) = 500 (axle speed)
500(AS) x 31(TC) = 15,500 (inches per min-traveled)
15,500(IM)/12(FT) = 1,291 (feet per min-traveled)
1,291(FM) x 60(HR) = 77,500 (feet per hour-traveled)
77,500(FH) x .000189(MM) = 14.65 MPH

These numbers would be for a 6:1GR
...NOT a 5:1GR

MY BAD

So, to be clear(er)
...in this scenario

A 6:1 GR = ~14.5 MPH top speed
...with pretty quick acceleration

A 5:1GR = ~17.5MPH top speed
...decent acceleration

A 3:1GR = ~29 MPH top speed
...but, would have very slow acceleration

 

[Master Hack]

How old is this grandbrat

He's 10 and grew up on a motorcycle. He's fearless, thinks the throttle works like an on/off switch.
I know, that close to the ground makes it faster. l dont want him to be dissapointed.
Its not a big deal to change a sprocket if necessary.

 

[Grizzlymi]

I could'nt grasp the manual transmission on my older sisters Ford Escort when I was 14. I bought a Yamaha Special 50cc when I was 15 with a 5 speed trans and picked it up right away and figured out the "manual trans". Hoped into my sisters Escort again and drove like champ.

And yes, faster and fearless means he's on the right path!!

 

[Master Hack]

Looking at my calcs above l agree 3.5:1 is too tall. I doubt that would even work at all.
This contraption probably be around 250# or less with the rider, so we'll start @ 5:1.
With that ratio, l'll need to see everybodys friend Jack Shaft. A 50 tooth sprocket on the axle wont leave much ground clearance.

And yes, faster and fearless means he's on the right path

He has grandpa yelling "NEVER LIFT" at him whenever he drives the "pile-o-scrap"

 

[Master Hack]

So, new plan...
Using a jackshaft, and 10/30 (motor to JS) then 18/30 (JS to axe)
using my abacus it comes out at 5:1 Please check my calcs.

l have officialy renamed the blue mobile scrap heap. Fromthis date forward it will be known as the "pile-o-scrap".

 

[Functional Artist]

Hey T,
Incorporating a Jack Shaft adds weight, friction/resistance & performance reduction/losses
...'cause of the more chain, bearings & gears

Remember, that little 48V 1,000W motor, has a ~1.2HP rating
...whereas your common ICE (internal combustion engine) like a Predator 212 has a ~6.5HP rating
&/so,
The losses of a JS wouldn't be noticed as much
...on a kart with a 6.5HP engine
...as they would be on kart with a 1.2HP motor

Q:
Where do ya plan on mounting the sprocket?

If the sprocket is really close to the wheel/tire
...it has much less chance of hitting the ground
...&/or "bottoming out"

Maybe something like on my Torsk (backbone chassis) kart

 

[Denny]

Terry, how are you dealing with the loss of Brian Wilson?