Grin ezee front hub with regen

[taiwwa]

It looks like this is a fairly new option. The ezee front geared hub motor with the clutch locked for regen capabilities.

So pros compared to other options from grin

—lower price

— lower weight. This thing looks like it is 3.8kg

—geared hub which gives you leverage advantage. Basically can go accelerate and decelerate faster.

Cons appear to be—

—geared hub has nylon gears which can wear out over time.

—smaller so cannot sustain extended heat dissipation

—no integrated torque arm splines like the all axle or GMAC so the torque arm setup is worse.

Lastly, while generally torque sensor bottom bracket setups are preferred, also cadence sensors allow for backpedal regen while torque sensing bottom bracket will not all for backpedal regen?

 

[E-HP]

Lastly, while generally torque sensor bottom bracket setups are preferred, also cadence sensors allow for backpedal regen while torque sensing bottom bracket will not all for backpedal regen?

The ERider than Grin sells, as well as others, have cadence sensing built in, in addition to torque sensing, and work with the pedal backwards setting.

 

[neptronix]

I think the shengyi sx2 is the better motor.. more efficient and lighter.. check how it performs in ebikes.ca's motor simulator compared.

 

[taiwwa]

I think the shengyi sx2 is the better motor.. more efficient and lighter.. check how it performs in ebikes.ca's motor simulator compared.

Eh, the price difference between these motors and the grin all axle is only like $300. Which isn’t that big a deal when you consider that all the other stuff in a kit costs $1000 anyways. It’s $1500 vs $1200 kit cost.

 

[neptronix]

I don't know anything about your target speed, terrain, etc, so i can't say.

Grin all axle is a great motor and should be loads more durable.

 

[taiwwa]

I don't know anything about your target speed, terrain, etc, so i can't say.

Grin all axle is a great motor and should be loads more durable.

I have some many hills and I’m designing the bike for some extreme hills and long descents because I’m tired of burning up my brakes and I’m wanting to increase the areas I can bike to.

 

[neptronix]

Can't go wrong with a motor that can do regen then. It could easily do 60% or more of stopping you. I used to run no mechanical rear brake, just ~700w of regen in the back, and 203mm disc at front. No problem going down a 10% grade for miles.

If you are using regen i would consider putting the motor on the back wheel. That will allow you to really crank the regen power up. Otherwise you have a traction problem on the front due to your weight balance on an upright bike, which is what i'm assuming you're building.

The problem is going up hill with a fixed gear motor of course. Two things can help:
- Ferrofluid ( very dramatically helps remove heat )
- The smallest rear wheel you can get away with. The smaller the wheel, the higher torque potential and efficiency under high load a motor has, which you could certainly use on extreme hills. A 24" rear on a 26" is a good compromise.

 

[neptronix]

Consider this scenario on a 26er bike. All axle + statorade injection.

This will do 31mph on the flats and hang pretty well uphill.
RH212 would do a bit better.

 

[taiwwa]

Can't go wrong with a motor that can do regen then. It could easily do 60% or more of stopping you. I used to run no mechanical rear brake, just ~700w of regen in the back, and 203mm disc at front. No problem going down a 10% grade for miles.

If you are using regen i would consider putting the motor on the back wheel. That will allow you to really crank the regen power up. Otherwise you have a traction problem on the front due to your weight balance on an upright bike, which is what i'm assuming you're building.

The problem is going up hill with a fixed gear motor of course. Two things can help:
- Ferrofluid ( very dramatically helps remove heat )
- The smallest rear wheel you can get away with. The smaller the wheel, the higher torque potential and efficiency under high load a motor has, which you could certainly use on extreme hills. A 24" rear on a 26" is a good compromise.

Eh, it will be a drop bar gravel like bike. I do wonder about front hubs and steep hills too. I’ve resorted to pushing the bike up hills but pushing an ebike is considerably worse.

But I once installed a bionx wheel into a bike and the weight being in the back made for a very harsh ride. Like, the vibrations from the road would sort of amplify to the handlebars because the weight of the back wheel was some sort of amplifying anchor for vibrations. I guess a regular bike would just see the back wheel bounce, but a direct drive motor in the back firmly plants it into the ground so all vibration goes through the bike.

 

[E-HP]

I have some many hills and I’m designing the bike for some extreme hills and long descents because I’m tired of burning up my brakes and I’m wanting to increase the areas I can bike to.

Install a temp sensor. Regen will heat up your motor pretty fast if you have extreme/long descents. You may need to pull over to let it cool. You could add a toggle switch to disconnect the brake switches and rely on your regular brakes.

 

[Chalo]

Install a temp sensor. Regen will heat up your motor pretty fast if you have extreme/long descents. You may need to pull over to let it cool.

This is a good reason not to use regen with geared hubs. The fact that they drag a lot more than DD hubs when coasting is another.

Also, which is less desirable maintenance: replacing brake pads more often because you don't have regen, or replacing your frame, fork, motor, and/or teeth because you do?

 

[taiwwa]

Consider this scenario on a 26er bike. All axle + statorade injection.

This will do 31mph on the flats and hang pretty well uphill.
RH212 would do a bit better.

View attachment 346658

I’m thinking I generally care more about power from a stop or below 10mph torque. Top end speed it’s always a little dangerous going above 20mph imo anyways.

 

[taiwwa]

This is a good reason not to use regen with geared hubs. The fact that they drag a lot more than DD hubs when coasting is another.

Also, which is less desirable maintenance: replacing brake pads more often because you don't have regen, or replacing your frame, fork, motor, and/or teeth because you do?

I happen to drive an electric car and before that hybrid cars and the regen meant dramatically less wear on the brake pads.

 

[Chalo]

I happen to drive an electric car and before that hybrid cars and the regen meant dramatically less wear on the brake pads.

Electric cars don't loosen their axle nuts when they use regen, like bicycle hub motors do.

 

[neptronix]

This is a good reason not to use regen with geared hubs. The fact that they drag a lot more than DD hubs when coasting is another.

Also, which is less desirable maintenance: replacing brake pads more often because you don't have regen, or replacing your frame, fork, motor, and/or teeth because you do?

torque arms completely solve this problem.

 

[Chalo]

torque arms completely solve this problem.

I have seen several axles spun through the flats on torque arms. If you completely solve that problem, then you get broken axles as many here have demonstrated.

The most expedient and effective solution is to only have motor torque twist the axle in one direction.

 

[neptronix]

Eh, it will be a drop bar gravel like bike. I do wonder about front hubs and steep hills too. I’ve resorted to pushing the bike up hills but pushing an ebike is considerably worse.

So 29" wheels?
What type of axle does the bike have? i'm betting it's not a regular "9mm" QR.

If so, i believe the all axle is the only motor that will work.

But I once installed a bionx wheel into a bike and the weight being in the back made for a very harsh ride. Like, the vibrations from the road would sort of amplify to the handlebars because the weight of the back wheel was some sort of amplifying anchor for vibrations.

This is certainly the case with rear hub motors, especially if they have very thick spokes.

Another issue is that you'll just be going faster. The ride will be bumpier. Just the case with any acoustic bike to electric bike conversion.

Consider a suspension seatpost of mid to high quality for taking the beating out of the rear.

Motorwise i'd consider this scenario if your speed requirements are not high:

Motor Simulator - Tools



If you are going to use regen and put this on a front fork, then i would limit the power of the regen significantly down to 300w and use some mechanical braking. For the rear, we could go up to ~700w, which is close to the efficiency sweet spot of the motor btw.

If you go the front route also, i would make sure you have a wide tire in front. There can be traction issues with the front of a bike because it has a very low amount of human weight on it relative to the rear.

 

[neptronix]

I have seen several axles spun through the flats on torque arms. If you completely solve that problem, then you get broken axles as many here have demonstrated.

The most expedient and effective solution is to only have motor torque twist the axle in one direction.

No problem here doing 6kw out, 1kw in on a mountain bike with grin torque arms on both sides and 0mm of play in the assembly.

This guy is not looking for a hot rod and his bike probably doesn't have axle flats in the first place so this may be a moot point.

 

[gromike]

But I once installed a bionx wheel into a bike and the weight being in the back made for a very harsh ride. Like, the vibrations from the road would sort of amplify to the handlebars because the weight of the back wheel was some sort of amplifying anchor for vibrations. I guess a regular bike would just see the back wheel bounce, but a direct drive motor in the back firmly plants it into the ground so all vibration goes through the bike.

I enjoy watching my back wheel going up and down, though that's on a bike with rear suspension.

 

[taiwwa]

So 29" wheels?
What type of axle does the bike have? i'm betting it's not a regular "9mm" QR.

If so, i believe the all axle is the only motor that will work.



This is certainly the case with rear hub motors, especially if they have very thick spokes.

Another issue is that you'll just be going faster. The ride will be bumpier. Just the case with any acoustic bike to electric bike conversion.

Consider a suspension seatpost of mid to high quality for taking the beating out of the rear.

Motorwise i'd consider this scenario if your speed requirements are not high:

Motor Simulator - Tools

View attachment 346681

If you are going to use regen and put this on a front fork, then i would limit the power of the regen significantly down to 300w and use some mechanical braking. For the rear, we could go up to ~700w, which is close to the efficiency sweet spot of the motor btw.

If you go the front route also, i would make sure you have a wide tire in front. There can be traction issues with the front of a bike because it has a very low amount of human weight on it relative to the rear.

i have two older road bikes that I would consider installing this motor on. One has quick release and the other is thru axle.

from my research, the integrated Torque arm interface of the all axle prevents nut loosening over time. The other motors will experience nut loosening over time.

wanting to limit Regen on the front also appears to be an argument for the all axle on the front since without the reduction gears it will be reduced force of regen deceleration

a suspension seat post is great but it wouldn’t stop vibration transmission to the handlebars.

 

[MusicCityEVs]

It looks like this is a fairly new option. The ezee front geared hub motor with the clutch locked for regen capabilities.

So pros compared to other options from grin

—lower price

— lower weight. This thing looks like it is 3.8kg

—geared hub which gives you leverage advantage. Basically can go accelerate and decelerate faster.

Cons appear to be—

—geared hub has nylon gears which can wear out over time.

—smaller so cannot sustain extended heat dissipation

—no integrated torque arm splines like the all axle or GMAC so the torque arm setup is worse.

Lastly, while generally torque sensor bottom bracket setups are preferred, also cadence sensors allow for backpedal regen while torque sensing bottom bracket will not all for backpedal regen?

Greetings from Nashville from this first-time poster.

Great topic, taiwaa! I like regenerative braking as much if not more for the brake pad wear reduction vs the efficiency gains. I like the efficiency gains as my previous 3 vehicles were hybrids and on those 3 sedans my primary reason for choosing the hybrid option was for the efficiency. Greatly reducing my brake wear was icing on the cake!

I started doing some deeper research into regenerative braking for what will be my first ever ebike builds. After watching many hours of YouTube vids I'm pretty sure I've narrowed it down to one of two motors and they are the Ezee and the Shengyi SX1.

 

[E-HP]

I happen to drive an electric car and before that hybrid cars and the regen meant dramatically less wear on the brake pads.

EVs have cooling systems designed to shed the motor heat. A geared hub has no pathway to shed the heat, so you may want to run ATF in the motor or something like that to transfer the heat.

 

[neptronix]

In terms of surviving some epic prolonged hill climb, AFAIK the ideal cooling fluid for geared hub motors seems yet to be discovered.

We have a yet to be tested candidate:
Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

 

[nicobie]

I happen to drive an electric car and before that hybrid cars and the regen meant dramatically less wear on the brake pads.

Brake pads are cheap and easy to replace.