Hub motor advise, if you got a minute. Please.

[Tater salad]

I have a e-bike that I’d like to upgrade. It’s my daily driver and has been for the last three years so I’m not completely wet behind the ears but I’m just a shade tree engineer at best and I haven’t been able to pick a motor because I don’t fully understand Kv, Kt, or any of the parameters that determine those criteria or where to find said parameters for the hubs I’m looking at (Amazon, eBay, Ali….). Anyway.
I’d like to be able to go 40+ mph without too much pedaling effort, preferably throttle only. Is this possible using a em3ev jumbo shark battery? Or should I go 60v? I have a G062 but have seen with help from a contributor on here that the G062’s Kv will limit my top end on 52 v system but I really like that jumbo shark battery. Will your average 48v1500 hub give me 40 mph with a 52v system? I have a 40 amp KT here so I figure I’ll start with that but I have no first hand experience and while no prohibitively expensive parts do cost money. I need some advise yall.

 

[neptronix]

You want a much bigger battery than what em3ev has to offer because 40mph will use about 2kw continuous, and over 3kw to accelerate.

Think more along the lines of 30AH or higher.

leafbike 1.5kw would be great for this application, very efficient at high RPM. 1.5kw rated but in reality will do 2kw on the flats for extended periods of time. ( it's under-rated )

You also want a full suspension bike for this, unless your roads are always smooth.

 

[E-HP]

At 52V and 60A, you can almost get there with a 3T Leaf motor (17.49Kv). Won't the the kind of acceleration the Leaf motors are capable of though. As neptronix said, you need a lot of battery with good cells for 60A.

(Kv adjusted for 3T Leaf):

 

[neptronix]

Yeah, 3T is too much, notice we're amp walled at 60A

Here's an actual 5T..


If we order a 4T instead, we're doin' maybe ~43mph and probably drawing 45a continuous..
.. so we need a battery with a max current rating of 60A or preferably higher.

 

[AdR]

My setup: leaf 1500/11.6 kv. Battery 16S charged to 63V, spintend 120/240 amp controller. 24 inch wheel. Hit 40mph fresh of the charger. Will cruise 30+ with no issues

 

[Tater salad]

You want a much bigger battery than what em3ev has to offer because 40mph will use about 2kw continuous, and over 3kw to accelerate.

Think more along the lines of 30AH or higher.

leafbike 1.5kw would be great for this application, very efficient at high RPM. 1.5kw rated but in reality will do 2kw on the flats for extended periods of time. ( it's under-rated )

You also want a full suspension bike for this, unless your roads are always smooth.

Right, I forgot. It’s an Ariel Rider Kepler. Hard tail but I’m in Florida and this bike is for around town. I’m using Allscapes and I weigh 225. So yea, 26 x 4..
If I went ahead and jumped to 72 v would my bike still have any bicycle like characteristics at all? In the pedaling department? I like helping some. That was a motivating factor in the 52 v thing. That and the lack of a battery in the 60 v arena that doesn’t cost $1,900!! Or is”60v 50ah 16s4p”.

 

[Tater salad]

My setup: leaf 1500/11.6 kv. Battery 16S charged to 63V, spintend 120/240 amp controller. 24 inch wheel. Hit 40mph fresh of the charger. Will cruise 30+ with no issues

 

[Tater salad]

My setup: leaf 1500/11.6 kv. Battery 16S charged to 63V, spintend 120/240 amp controller. 24 inch wheel. Hit 40mph fresh of the charger. Will cruise 30+ with no issues

What is “spintered”? Is that Shunted? I’m having trouble with your numbers. Or is it a programmable controller?

 

[E-HP]

If I went ahead and jumped to 72 v would my bike still have any bicycle like characteristics at all? In the pedaling department? I like helping some.

That's up to you. You have the option of being lazy, which is easy to take advantage of, so it's more about your self control than anything else.

 

[neptronix]

What is “spintered”? Is that Shunted? I’m having trouble with your numbers. Or is it a programmable controller?

Spintend is a brand of VESC controller.

 

[neptronix]

If I went ahead and jumped to 72 v would my bike still have any bicycle like characteristics at all? In the pedaling department? I like helping some. That was a motivating factor in the 52 v thing. That and the lack of a battery in the 60 v arena that doesn’t cost $1,900!! Or is”60v 50ah 16s4p”.

It would feel more like a motorcycle after about 2.5kw.



I needed a ~60T chainring on my 26" wheeled bike to pedal up to 40mph. That might be a problem for your frame.
This build would be a lot easier if you dropped your top speed requirement to 35mph.

 

[Chalo]

If I went ahead and jumped to 72 v would my bike still have any bicycle like characteristics at all? In the pedaling department?

By the time your bike exceeds 30mph, you have kissed that option goodbye. You'll need a big heavy motor and a big heavy battery, and above that speed you won't be contributing more pedal power than you add drag by thrashing your legs around.

26 x 4" fat tire e-bikes aren't for pedaling. They fight you for every inch of progress.

 

[neptronix]

35mph is a really good speed to pedal and get exercise in. Most bikes can fit a big chainring to get good cadence.
40mph is hard to get the cadence right on, but i also pedal at that speed even if it's at hamster speed.

 

[Chalo]

35mph is a really good speed to pedal and get exercise in. Most bikes can fit a big chainring to get good cadence.
40mph is hard to get the cadence right on, but i also pedal at that speed even if it's at hamster speed.

If exercise is the criterion, then that works. But pedaling at 40 costs range rather than adding to it.

My favorite power and speed calculator says at 40mph, pedaling at 100 RPM costs 250W of drag vs pedaling at 1 RPM. And they're probably not assuming street clothes.

 

[amberwolf]

Moved thread out of bicycle mechanical and structural since it's not a mechanical or structural question, and into ebike technical.