Accleration - the how, what and why?

LBerg

New Member
Region
USA
I've spent a week researching, including this forum and a ton of youtube videos. Could still use some clarity on acceleration (mainly throttle only but with pedals too).

I'm still not quite sure what affect acceleration. Is it mainly watt rating (500w vs 750)? Voltage? I know the watt hours equation, but unsure about acceleration.

FYI: All the bikes I'm looking at seem to have a rear hub motor, so you can eliminate acceleration differences with the motor position.

Obviously your weight and the bikes weight is a factor, but those I'm looking at are all very similar.

Thank you!
 

indianajo

Well-Known Member
Watts is a big game these days. Peak watts, rms watts, government watts, what? Reason the appliance industry quit using it, the measurement technique can affect the result so badly. Watthours is how far you can go on one charge, not how fast you accelerate.
Frankly, your acceleration is a big dice game. the only choice you have is, direct drive hub motor (ultra cheap, slow acceleration, good high speed performance, drags unpowered) or geared hub motor (middle expensive, faster acceleration, just okay high speed performance, does not drag unpowered). I have a Mac12t "500w" geared hub motor and it accelerates faster than I can unpowered at age 70. But age 50 I could pick the front tire up with my feet, and the hub motor will not do that. Before I had a "1300 W" ebikeling geared hub motor, and it didn't accelerate faster than the Mac12t. Controller was 30 amp rated, battery was 48v. Wore out the ebikeling motor @ ~4500 miles.
If you buy a bike you can test at a store before purchase, you will know what you are getting. If you buy internet, you just bought a good review, or no review. The store is supposed to handle any problems you have. With e-bikes it is probably worth it. IMHO. We have only one store closer than 70 miles, he sells one brand, and a guy I met on the street that bought from him says the dealer is clueless about repairs. It is the 2nd most expensive brand, Pedego, and the Stretch model is ~$4000 and one size doesn't fit all(me). So I bought an unpowered small cargo bike, 2 aftermarket power wheels, and 3 aftermarket batteries, and threw some away until I had what I wanted. At $3240 I had a small stretch cargo bike that I liked with 24 speeds 840 wh and a 2nd "1000 W" DD hub motor w/ wheel that worked but I didn't like.
Happy shopping.
 
Last edited:

harryS

Well-Known Member
If you want more acceleration out of a hub motor bike, use a smaller wheel, lighten the rims, use a light tire, increase the current, choose a bigger diameter motor, and add more voltage. It's not like you can do much about these variables with a ready-to-sell bike other than go with 52V and the highest amp controller offered.

Acceleration with pedal assist is purely subjective. A storng rider accellerates more than a weak rider. Throttle is the only way to discuss it. There is more to enjoying a bike than acceleration, so pick something you like riding first.
 

Timpo

Well-Known Member
I think this topic has been beaten to death on Rad Power Forum.

Just because one motor can drain 750W of energy, doesn't mean other motor draining the same 750W will act in the exact same way. (
(thus, people are replacing their motor to "real 750W motor")
It has something to do with winding turns, magnets, coils, etc.
 

fooferdoggie

Well-Known Member
amps is what the motor needs to accelerate faster.
I find the best way to accelerate is put the bike into the largest cog and use your legs too. I can really get the bike up and running. its almost faster then with my bosch mid drive. one or two peddle revelations shift and keep that up and you will be flying from a dead stop. I learned that on my recumbent.
 

LBerg

New Member
Region
USA
Watts is a big game these days. Peak watts, rms watts, government watts, what? Reason the appliance industry quit using it, the measurement technique can affect the result so badly. Watthours is how far you can go on one charge, not how fast you accelerate.
Frankly, your acceleration is a big dice game. the only choice you have is, direct drive hub motor (ultra cheap, slow acceleration, good high speed performance, drags unpowered) or geared hub motor (middle expensive, faster acceleration, just okay high speed performance, does not drag unpowered). I have a Mac12t "500w" geared hub motor and it accelerates faster than I can unpowered at age 70. But age 50 I could pick the front tire up with my feet, and the hub motor will not do that. Before I had a "1300 W" ebikeling geared hub motor, and it didn't accelerate faster than the Mac12t. Controller was 30 amp rated, battery was 48v. Wore out the ebikeling motor @ ~4500 miles.
If you buy a bike you can test at a store before purchase, you will know what you are getting. If you buy internet, you just bought a good review, or no review. The store is supposed to handle any problems you have. With e-bikes it is probably worth it. IMHO. We have only one store closer than 70 miles, he sells one brand, and a guy I met on the street that bought from him says the dealer is clueless about repairs. It is the 2nd most expensive brand, Pedego, and the Stretch model is ~$4000 and one size doesn't fit all(me). So I bought an unpowered small cargo bike, 2 aftermarket power wheels, and 3 aftermarket batteries, and threw some away until I had what I wanted. At $3240 I had a small stretch cargo bike that I liked with 24 speeds 840 wh and a 2nd "1000 W" DD hub motor w/ wheel that worked but I didn't like.
Happy shopping.
Lots of great info in there. I appreciate it.

Thanks to everyone else as well (looks like the forum doesn't have multi-quote capability).

All the bikes I'm looking at are fat tires and heavy (including a 20" folder). I'm sure all of that hinders quick acceleration :) I've just always enjoyed accelerating fast (in things like carts) vs top speed. I'm guessing I'll be happy with most options.

Harry mentioned smaller wheels, so maybe a 20" folder would accelerate faster than a big fat tire 26"?
 

indianajo

Well-Known Member
Harry mentioned smaller wheels, so maybe a 20" folder would accelerate faster than a big fat tire 26"?
Yeah, but rattle your teeth worse if you run through a pothole or over a pavement separator sticking up 2". Fat tire would help. I ride a 26"x2.1" tire at about 45 psi. No front suspension fork available on cargo bikes.
 

antboy

Well-Known Member
Lots of great info in there. I appreciate it.

Thanks to everyone else as well (looks like the forum doesn't have multi-quote capability).

Harry mentioned smaller wheels, so maybe a 20" folder would accelerate faster than a big fat tire 26"?
I don't know about mobile, but one way to multi-quote is to hit reply, like I've done here.

Then find the other comment you want to quote, and hit reply to that... It'll add the quote to your exisitng reply.
I've spent a week researching, including this forum and a ton of youtube videos. Could still use some clarity on acceleration (mainly throttle only but with pedals too).


Obviously your weight and the bikes weight is a factor, but those I'm looking at are all very similar.

Thank you!

Like so. :)

Also, if you want to call out a user without quoting, use the @ symbol then start typing their username, like a twittle handle... as you do, you should see a list of names appear to click on, @LBerg
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Grin has a spreadsheet program that demonstrates most of this pretty clearly. Most find the calculations scary close to reality....

All else being equal, it IS about the number of turns of wire on the armature, which is related directly to the rpm the motor is rated at. MAC motors, which are available in 6 (MAC 6t) through 12 turn (MAC 12t) versions can illustrate some of the differences pretty clearly. Look at the starting torque differences, where they are most efficient, and down in the lower left, the motor rpm rating. Check it out. MAC 12T and 8T shown, but feel free to play with voltage, wheel size or anything else that might interest you. Just click on the "Simulate" button after making your changes.

https://ebikes.ca/tools/simulator.h...C35&cont_b=C35&motor_b=MMAC8T&batt_b=B4823_AC
 

LBerg

New Member
Region
USA
I don't know about mobile, but one way to multi-quote is to hit reply, like I've done here.

Then find the other comment you want to quote, and hit reply to that... It'll add the quote to your exisitng reply.


Like so. :)

Also, if you want to call out a user without quoting, use the @ symbol then start typing their username, like a twittle handle... as you do, you should see a list of names appear to click on, @LBerg
Great, thank you!

Grin has a spreadsheet program that demonstrates most of this pretty clearly. Most find the calculations scary close to reality....

All else being equal, it IS about the number of turns of wire on the armature, which is related directly to the rpm the motor is rated at. MAC motors, which are available in 6 (MAC 6t) through 12 turn (MAC 12t) versions can illustrate some of the differences pretty clearly. Look at the starting torque differences, where they are most efficient, and down in the lower left, the motor rpm rating. Check it out. MAC 12T and 8T shown, but feel free to play with voltage, wheel size or anything else that might interest you. Just click on the "Simulate" button after making your changes.

https://ebikes.ca/tools/simulator.h...C35&cont_b=C35&motor_b=MMAC8T&batt_b=B4823_AC
Nice, I'll check it out.