Dengfu E22 Frame Thread

[Neeko DeVinchi]

Just in case, here is the instructions for the DZ41 display

 

[Cigales]

What do you guys think of these from ebay? Better than factory or any close to christini?
View attachment 91407

I tried buying one of those off of aliexpress.

The seller marked as posted. Then he contact me to say he has no stock. And can't get anymore. I ask for refund. But because he already said it was posted, it wasn't easy. I lodge complaint with Aliexpress, but they won't act because, aparently seller had already posted it. And I had to wait up to 60 days for it to arrive. So I contacted my bank and requested a credit card charge back.

Hi,
I'm trying to get hold of a a chainring but it's not easy and don't want (at this stage at least) to spend $100 for the ChristiniBicycles chainring adaptor.
Did you guys ever find the right one for an bafang M620 (ISIS type)?

What about the bolt/screw chainring dimensions, I've seen 6.5mm and 8.5mm ones.

This is what I've found until now:

21.69￡ |SING YIU Bafang Ebike M500 M510 M600 M620 G510 G521 Bicycle Bafang Mid Motor Spider Chain Ring Adapter 104BCD bicycle crankset| | - AliExpress

 

[Neeko DeVinchi]

That looks pretty cool. Better than the 500C? I don't know. The minimal UI is nicer and it's certainly a shed-load cheaper...

Well, it's a smaller unit than the 500C display but with a bigger screen.

I'm just thankful I can finally run a display further outboard on my 820mm wide bars without issue.

Both displays seem to be equal in terms of protrusion.

And the DZ41 does seem more ergonomic

 

[Mabman]

Well, it's a smaller unit than the 500C display but with a bigger
View attachment 92407
And the DZ41 does seem more ergonomic

I don't know Neeko that pic illustrates to me that I would probably be hitting the mode button as well when fumbling around for the selectors? Especially when wearing gloves.

I use the 500c and the flat buttons weren't working well for me and I dribbled some super glue on them to make enough of a protrusion that I could feel it with my thumb, even with gloves on. I'll probably stick with the 500c but this one will make a good option if cheaper for those that are not satisfied with the DC18 display.

 

[Tomteam]

Hi,
I'm trying to get hold of a a chainring but it's not easy and don't want (at this stage at least) to spend $100 for the ChristiniBicycles chainring adaptor.
Did you guys ever find the right one for an bafang M620 (ISIS type)?

What about the bolt/screw chainring dimensions, I've seen 6.5mm and 8.5mm ones.

This is what I've found until now:

21.69￡ |SING YIU Bafang Ebike M500 M510 M600 M620 G510 G521 Bicycle Bafang Mid Motor Spider Chain Ring Adapter 104BCD bicycle crankset| | - AliExpress

It looks good.
You will tell us how it works if you decide to buy it.

 

[CaptainBobt]

I'm still waiting for my e22 kit and have no idea what brakes I need but you are saying you don't need brake sensors. How it that possible since the kit comes with 3 pin plug and how does the motor start with out brake sensors? Is there a way to disable the brake sensor/ bypass it on the display?

Brakes sensors have nothing to do with your display all they do is cut power off to the motor when the levers are pulled you don't need them for the motor to operate normally you can levers the wires for the sensors unplugged and go on your merry way with any brake lever your heart desires..

 

[CaptainBobt]

Brakes sensors have nothing to do with your display all they do is cut power off to the motor when the levers are pulled you don't need them for the motor to operate normally you can levers the wires for the sensors unplugged and go on your merry way with any brake lever your heart desires..

I personally don't like them, they abruptly cut power to the motor wich can be trouble some in very tight wooded areas were I ride, I like to modulate the speed only with brakes, not both power and speed, I have a motorcycle background so it's a personal preference.

 

[bram.biesiekierski]

Hi,
I'm trying to get hold of a a chainring but it's not easy and don't want (at this stage at least) to spend $100 for the ChristiniBicycles chainring adaptor.
Did you guys ever find the right one for an bafang M620 (ISIS type)?

What about the bolt/screw chainring dimensions, I've seen 6.5mm and 8.5mm ones.

This is what I've found until now:

21.69￡ |SING YIU Bafang Ebike M500 M510 M600 M620 G510 G521 Bicycle Bafang Mid Motor Spider Chain Ring Adapter 104BCD bicycle crankset| | - AliExpress

I ended up buying the expensive Christini one. I used it with a 36t chainring, and a mixed 12spd drivetrain. Using an e13 Helix cassette, and Sram GX mech.

It didn't go well. In less than 50km, the rear cassette was toast. The teeth were being rolled/worn over, and the chain hopping over the cassette teeth under load.

I think the high power motor, coupled with the smaller 36t chainring put way too much force through the drivetrain.

I have now put the standard bafang chainring on, and moved to a Box Prime 11-50t - 9spd drivetrain.

The standard 44t bafang chainring, and the Box Prime 11t highest gear gives me the exact same ratio as the 36t chainring and 9t - e13 highest gear.

I do lose gear range with this combo. But that fine, by using the standard bafang chainring, I lose all the range from the low end of the gear range.

The 9spd system is chunky. It seams tough. And it was super easy to setup. On a 12spd drivetrain, half a turn out on the barrel adjuster will cause havoc with gear indexing. On the 9spd, you don't even need a barrel adjuster. You can literally just adjust the cable at the deralier by eye, and the steps between gears are so large, you can't really muck it up.

 

[Neeko DeVinchi]

I ended up buying the expensive Christini one. I used it with a 36t chainring, and a mixed 12spd drivetrain. Using an e13 Helix cassette, and Sram GX mech.

It didn't go well. In less than 50km, the rear cassette was toast. The teeth were being rolled/worn over, and the chain hopping over the cassette teeth under load.

I think the high power motor, coupled with the smaller 36t chainring put way too much force through the drivetrain.

I have now put the standard bafang chainring on, and moved to a Box Prime 11-50t - 9spd drivetrain.

The standard 44t bafang chainring, and the Box Prime 11t highest gear gives me the exact same ratio as the 36t chainring and 9t - e13 highest gear.

I do lose gear range with this combo. But that fine, by using the standard bafang chainring, I lose all the range from the low end of the gear range.

The 9spd system is chunky. It seams tough. And it was super easy to setup. On a 12spd drivetrain, half a turn out on the barrel adjuster will cause havoc with gear indexing. On the 9spd, you don't even need a barrel adjuster. You can literally just adjust the cable at the deralier by eye, and the steps between gears are so large, you can't really muck it up.

You've raised a good point @bram.biesiekierski. Technically, I'm not running my M620 with 160nm of torque. So with the Christini chainring and a 32t, I'm able to get away with a power delivery which isn't destructive on the chain/cassette/chainring/jockey wheels etc.

My friends have asked whether the M620 requires the mechanical advantage a 32t chainring would offer. I'll bare your experiences in mind. Appreciate your feedback dude

 

[Old Biker]

You've raised a good point @bram.biesiekierski. Technically, I'm not running my M620 with 160nm of torque. So with the Christini chainring and a 32t, I'm able to get away with a power delivery which isn't destructive on the chain/cassette/chainring/jockey wheels etc.

My friends have asked whether the M620 requires the mechanical advantage a 32t chainring would offer. I'll bare your experiences in mind. Appreciate your feedback dude

Had a wee run last night and split the cog on the cassette going to swap to a slx 11speed cassette and start greasing things !!!

 

[bram.biesiekierski]

You've raised a good point @bram.biesiekierski. Technically, I'm not running my M620 with 160nm of torque. So with the Christini chainring and a 32t, I'm able to get away with a power delivery which isn't destructive on the chain/cassette/chainring/jockey wheels etc.

My friends have asked whether the M620 requires the mechanical advantage a 32t chainring would offer. I'll bare your experiences in mind. Appreciate your feedback dude

A gear ratio is a combination of both the chain ring, and the selected rear gear. Changing just the chainring will obviously affect the ratio achieved from any given gear. But it won't stop you from simply changing up or down to get back to the desired ratio. (Provided that ratio is achievable in your overall gear range). Its the ratio that is the important part of the equation.

When you ride, you pick the ratio that suits what your riding up/down. You do this instinctively, when you feel your cadence is to high and you want to go faster, you shift up gear. When you feel your lugging and dont have the power needed to maintain your speed, you shift down gear. As long as you can find a particular ratio within your entire gear range, then it doesn't really matter what size your chainring is. It's the ratio between the chainring and the selected rear gear that is important. Not simply just the chainring size.

The problem with smaller chainrings, is it increases the force in the chain, and it increases the force through each tooth of the whole drivetrain, at a given torque input.

For example, if you use the exact same ratio, but spread it over less teeth at the front, and less teeth at the rear, then you are logically putting more force into each tooth, at a given torque input.

As I mentioned above, 36t chainring and 9t high gear, is EXACTLY the same ratio as 44t chainring, and 11t high gear. It will make no difference in acceleration or speed, because its the exact same ratio.
36:9 = 4:1
44:11 = 4:1
The only difference between those 2 setups is that the 36:9 is going to have less teeth in contact with the chain. Increasing wear, and increasing the likely hood of the chain riding up over the teeth and skipping under load. Which is exactly what was happening on all 6 or so of the higher gears on my e13/36t setup. It was so bad it didn't even last 50kms.

So, on something like a an e22 with the bafang ultra, (ie no shortage of torque) then I think you should go with the biggest chainring you can. The limiting factor of how big to go is going to be the ratio you get from your lowest gear. Aslong as your lowest gear ratio isn't too high for what you ride, then you should be alright. All the larger chainring is going to do is have you using lower gears to get your desired ratio.

Other considerations like ground clearance and weight obviously worth considering, but I dont think that will be an issue with the 44t standard chainring. And the extra weight is a drop in the ocean when your riding something like the e22 anyways.

The reason I originally chose the 36t was to try and match to my existing 12spd setup I already had. I tried to pick a chainring, that would give the range of ratios I thought it would most use. And try and place me in the middle of the range of available gears. So not too much off to either side of the cassette for the most common riding. The 36t did this. I found i rode the middle of the cassette mostly. But the downside was it put too much force into the chain, which overpowered the cassette.

 

[bram.biesiekierski]

Had a wee run last night and split the cog on the cassette going to swap to a slx 11speed cassette and start greasing things !!!

View attachment 92490

View attachment 92491

Oh wow. That's hectic. You literally stripped half the teeth off the tallest gear.

What was your drivetrain setup? Chainring size / brand of cassette etc

 

[Old Biker]

A gear ratio is a combination of both the chain ring, and the selected rear gear. Changing just the chainring will obviously affect the ratio achieved from any given gear. But it won't stop you from simply changing up or down to get back to the desired ratio. (Provided that ratio is achievable in your overall gear range). Its the ratio that is the important part of the equation.

When you ride, you pick the ratio that suits what your riding up/down. You do this instinctively, when you feel your cadence is to high and you want to go faster, you shift up gear. When you feel your lugging and dont have the power needed to maintain your speed, you shift down gear. As long as you can find a particular ratio within your entire gear range, then it doesn't really matter what size your chainring is. It's the ratio between the chainring and the selected rear gear that is important. Not simply just the chainring size.

The problem with smaller chainrings, is it increases the force in the chain, and it increases the force through each tooth of the whole drivetrain, at a given torque input.

For example, if you use the exact same ratio, but spread it over less teeth at the front, and less teeth at the rear, then you are logically putting more force into each tooth, at a given torque input.

As I mentioned above, 36t chainring and 9t high gear, is EXACTLY the same ratio as 44t chainring, and 11t high gear. It will make no difference in acceleration or speed, because its the exact same ratio.
36:9 = 4:1
44:11 = 4:1
The only difference between those 2 setups is that the 36:9 is going to have less teeth in contact with the chain. Increasing wear, and increasing the likely hood of the chain riding up over the teeth and skipping under load. Which is exactly what was happening on all 6 or so of the higher gears on my e13/36t setup. It was so bad it didn't even last 50kms.

So, on something like a an e22 with the bafang ultra, (ie no shortage of torque) then I think you should go with the biggest chainring you can. The limiting factor of how big to go is going to be the ratio you get from your lowest gear. Aslong as your lowest gear ratio isn't too high for what you ride, then you should be alright. All the larger chainring is going to do is have you using lower gears to get your desired ratio.

Other considerations like ground clearance and weight obviously worth considering, but I dont think that will be an issue with the 44t standard chainring. And the extra weight is a drop in the ocean when your riding something like the e22 anyways.

The reason I originally chose the 36t was to try and match to my existing 12spd setup I already had. I tried to pick a chainring, that would give the range of ratios I thought it would most use. And try and place me in the middle of the range of available gears. So not too much off to either side of the cassette for the most common riding. The 36t did this. I found i rode the middle of the cassette mostly. But the downside was it put too much force into the chain, which overpowered the cassette.

It came with a 40t chainring and

Oh wow. That's hectic. You literally stripped half the teeth off the tallest gear.

What was your drivetrain setup? Chainring size / brand of cassette etc

It's got a 40t chainring, nx derailleur, and the cassette was a cheap knock off brand sunshine or sunburst or something,got a 11 50 slx so gonna try fit that!!! but yes drivetrain are an issue with this torque

 

[Neeko DeVinchi]

Their is no right or wrong approach to gearing preferences when it comes to ebike motors.

I somewhat understand your point @bram.biesiekierski. However, you've not taken two important aspects into consideration:-
1. Subject to the level of assist you're in, will depend on how much power the motor will produce (nominal and peak) and how much battery is used.
2. Torque (I.e. newton meters of torque) is a measurement of force.

Gear ratio is important (in my opinion), as it will eliminate the need to use higher levels of assist unnecessarily to compensate for gearing.

The argument of whether ebikes chew through chains, cassettes, chainring etc is somewhat nonsensical, as these items are consumable. And again, I chose to run my M620 at 20amps to only achieve 120nm of torque.

I still believe that the 104bcd spider is a better option compared to the stock 130bcd chainring/spider. But I do recognise that some may choose to use the E22 as speed pedelecs (or something along those lines). And prefer the speed advantage a bigger chainring offers.

Just for reference, I have not encountered any issues with my current setup with a 12spd chain, Shimano SLX M7100 derailleur and a 11-50t cassette

Paired with my Christini 104bcd spider adapter and a 32t chainring.

 

[Neeko DeVinchi]

Had a wee run last night and split the cog on the cassette going to swap to a slx 11speed cassette and start greasing things !!!

View attachment 92490

View attachment 92491

NX derailleurs (I'm assuming it came with NX in accordance with what Carbon Cycles advertised), might be the culprit behind the chain tension. If you can, I would look into swapping to GX derailleur only (no need to buy a shifter).

If it helps,

Security measure

www.ebay.co.uk

Keep a watchful eye on upcoming listings for good deals

 

[Old Biker]

Their is no right or wrong approach to gearing preferences when it comes to ebike motors.

I somewhat understand your point @bram.biesiekierski. However, you've not taken two important aspects into consideration:-
1. Subject to the level of assist you're in, will depend on how much power the motor will produce (nominal and peak) and how much battery is used.
2. Torque (I.e. newton meters of torque) is a measurement of force.

Gear ratio is important (in my opinion), as it will eliminate the need to use higher levels of assist unnecessarily to compensate for gearing.

The argument of whether ebikes chew through chains, cassettes, chainring etc is somewhat nonsensical, as these items are consumable. And again, I chose to run my M620 at 20amps to only achieve 120nm of torque.

I still believe that the 104bcd spider is a better option compared to the stock 130bcd chainring/spider. But I do recognise that some may choose to use the E22 as speed pedelecs (or something along those lines). And prefer the speed advantage a bigger chainring offers.

View attachment 92516
Just for reference, I have not encountered any issues with my current setup with a 12spd chain, Shimano SLX M7100 derailleur and a 11-50t cassette
View attachment 92517
Paired with my Christini 104bcd spider adapter and a 32t chainring.

Neeko I done 15 miles on it so only getting to know it in truth I would aim to run in eco1 on flattish ,eco 3 for hills , I'm thinking this wasnt a great cassette fitted to start with ,I'll see how it is with the slx fitted !

 

[Neeko DeVinchi]

Neeko I done 15 miles on it so only getting to know it in truth I would aim to run in eco1 on flattish ,eco 3 for hills , I'm thinking this wasnt a great cassette fitted to start with ,I'll see how it is with the slx fitted !

Good point

 

[CaptainBobt]

It came with a 40t chainring and

It's got a 40t chainring, nx derailleur, and the cassette was a cheap knock off brand sunshine or sunburst or something,got a 11 50 slx so gonna try fit that!!! but yes drivetrain are an issue with this torque

Ya I'd avoid any knock off cassette with these motors. I have a Bbhd fat bike that throws 150 NM + and has a scram 12 11-50gx no problems 2000 miles plus

It came with a 40t chainring and

It's got a 40t chainring, nx derailleur, and the cassette was a cheap knock off brand sunshine or sunburst or something,got a 11 50 slx so gonna try fit that!!! but yes drivetrain are an issue with this torque

 

[bram.biesiekierski]

Their is no right or wrong approach to gearing preferences when it comes to ebike motors.

I somewhat understand your point @bram.biesiekierski. However, you've not taken two important aspects into consideration:-
1. Subject to the level of assist you're in, will depend on how much power the motor will produce (nominal and peak) and how much battery is used.
2. Torque (I.e. newton meters of torque) is a measurement of force.

Gear ratio is important (in my opinion), as it will eliminate the need to use higher levels of assist unnecessarily to compensate for gearing.

The argument of whether ebikes chew through chains, cassettes, chainring etc is somewhat nonsensical, as these items are consumable. And again, I chose to run my M620 at 20amps to only achieve 120nm of torque.

I still believe that the 104bcd spider is a better option compared to the stock 130bcd chainring/spider. But I do recognise that some may choose to use the E22 as speed pedelecs (or something along those lines). And prefer the speed advantage a bigger chainring offers.

View attachment 92516
Just for reference, I have not encountered any issues with my current setup with a 12spd chain, Shimano SLX M7100 derailleur and a 11-50t cassette
View attachment 92517
Paired with my Christini 104bcd spider adapter and a 32t chainring.

With point 1.
At some stage, you are going to use the highest level assist, or go full throttle. You might not use it all the time. But there will be times when you do. So the drivetrain must be able to hold up to the highest output from the motor, plus the combined output from the human rider aswell.

There is no point in having an ultra equipped bike, but not being unable to use the full output. That's like having a turbocharged car, but never getting it into boost. It's pointless. You may aswell ride something that is equipped with a lower output motor like a bosch/shimano, or a smaller model bafang, and not suffer the weight penalty of the ultra.

As for point 2.
Im well aware of torque.
The motor has a peak torque of 160nm. That is equivelant to a 1 meter long lever, with 16kgs of force on the end. It's substantial. What is not clear Is if that is measured at the output of the motor and combined internal gearing, or just directly from the motor rotor shaft. In any case it's alot. I suspect it's taken after the internal motor gearing. As I very much doubt the motor rotor itself could get anywhere near 160nm. It would have to be after a bunch of gear reductions internal to the motor that would multiply the torque.

Ontop of that 160nm from the motor, if the rider is pedalling simultaneously at max assist, then it could potentially be 200-250nm (or even higher). That's equivelant to 20-25kgs on the end of a 1m lever. The chainring is only about 200mm in diameter, which means the radius is only about 100mm. That means that the chain will see about 200-250kgs of linear force. The smaller the chainring, the larger the force multiplication into the chain.

At the rear end, that linear force in the chain is again converted back into rotational force (torque) at the cassette/rear wheel. This time though, the larger the cog, the more the torque multiplication. And the smaller the cog, the less torque.

Using larger chainring, and larger rear cog size, reduces the force through the chain, and into each cog tooth, for any given input, at any given ratio.

And yes i understand that a drivetrain could be considered consumable. But not at 50km intervals like I had, or 15 mile intervals like Old Biker got from his. That is ridiculous. That's like replacing your drivetrain every time you go for a ride. Maybe 4000-5000km intervals would be acceptable. That's not unreasonable I don't think.

 

[bram.biesiekierski]

Also 100% agree with Neekos opinion of the NX drivetrain, and especially derailer. It is a POS. Having ridden and owned pretty much all the Sram Eagle systems (NX, GX X01, XX1), the GX and above are far superior to the NX/SX range.

The NX pulley wheels don't even have ball bearings, they are rudimentary plain bearings. Literally a metal sleeve rotating on a rod. That causes the pully wheels to have lots of play, which causes massive problems with gear indexing on a tightly spaced 12spd system. Once there is a little use/wear in the NX derailers, it's almost impossible to correctly index the gearing.

And the NX cassette is also a big hunk of shit. But I believe that's mostly because they use shimano HG freehub as opposed to the Sram XD. What happens with the NX cassette is that the individual cassette cogs chew into the splines of the HG freehub. The HG setup has splines the whole length of the freehub, so cassette manufacturers simply spline each cassette cog to the freehub. This means each cassette cog can individually chew its way into the splines. Terrible design. Whether you like Sram or not, you have to admit the XD driver is infinitely better than the shimano HG.

 

[CaptainBobt]

With point 1.
At some stage, you are going to use the highest level assist, or go full throttle. You might not use it all the time. But there will be times when you do. So the drivetrain must be able to hold up to the highest output from the motor, plus the combined output from the human rider aswell.

There is no point in having an ultra equipped bike, but not being unable to use the full output. That's like having a turbocharged car, but never getting it into boost. It's pointless. You may aswell ride something that is equipped with a lower output motor like a bosch/shimano, or a smaller model bafang, and not suffer the weight penalty of the ultra.

As for point 2.
Im well aware of torque.
The motor has a peak torque of 160nm. That is equivelant to a 1 meter long lever, with 16kgs of force on the end. It's substantial. What is not clear Is if that is measured at the output of the motor and combined internal gearing, or just directly from the motor rotor shaft. In any case it's alot. I suspect it's taken after the internal motor gearing. As I very much doubt the motor rotor itself could get anywhere near 160nm. It would have to be after a bunch of gear reductions internal to the motor that would multiply the torque.

Ontop of that 160nm from the motor, if the rider is pedalling simultaneously at max assist, then it could potentially be 200-250nm (or even higher). That's equivelant to 20-25kgs on the end of a 1m lever. The chainring is only about 200mm in diameter, which means the radius is only about 100mm. That means that the chain will see about 200-250kgs of linear force. The smaller the chainring, the larger the force multiplication into the chain.

At the rear end, that linear force in the chain is again converted back into rotational force (torque) at the cassette/rear wheel. This time though, the larger the cog, the more the torque multiplication. And the smaller the cog, the less torque.

Using larger chainring, and larger rear cog size, reduces the force through the chain, and into each cog tooth, for any given input, at any given ratio.

And yes i understand that a drivetrain could be considered consumable. But not at 50km intervals like I had, or 15 mile intervals like Old Biker got from his. That is ridiculous. That's like replacing your drivetrain every time you go for a ride. Maybe 4000-5000km intervals would be acceptable. That's not unreasonable I don't think.

I agree with both of you there is no right or wrong with gearing with an ebike, And using crap will yeild crappy walks home.IMO Its user preference but that user better understand the limitations of his gear. . Remember Force required for a desired result is only a direct product of the resistance such force has to overcome. If we plan on using gearing to our advantage with a 160nm motor we best understand the place time, and limits when using them, as well as the quality of the products we decide to implement.

 

[bram.biesiekierski]

I agree with both of you there is no right or wrong with gearing with an ebike, And using crap will yeild crappy walks home.IMO Its user preference but that user better understand the limitations of his gear. . Remember Force required for a desired result is only a direct product of the resistance such force has to overcome. If we plan on using gearing to our advantage with a 160nm motor we best understand the place time, and limits when using them, as well as the quality of the products we decide to implement.

I get what your saying about the force required is only going to be equal to the resistance it has to overcome. But that doesn't change anything.

That resistance is primarily always going to be accelerating the 120+ kgs of bike and rider either up the trail, or faster along the trail. Using a lower gear ratio, while requesting the maximum amount of torque from the motor (eg max throttle, or max pedal assist) is always going to result in the exact same amount of output from the motor.

The only difference is It's just going to result in a higher rate of acceleration in the lower gear ratio. Which is going to make it "feel" better, or feel easier on the motor.

That motor is still outputting its max output. That is still getting transformed by the chainring into linear tension force in the chain, it's still getting transformed back into rotational torque in the rear cassette. That is still getting transformed into linear force at the point where the tyre meets the ground.

The only caveat to that is if you lift or spin a wheel, or operate the motor outside of its rotational RPM window where it produces its rated torque, or if the battery/controller is limiting the input to the motor.

 

[CaptainBobt]

I get what your saying about the force required is only going to be equal to the resistance it has to overcome. But that doesn't change anything.

That resistance is primarily always going to be accelerating the 120+ kgs of bike and rider either up the trail, or faster along the trail. Using a lower gear ratio, while requesting the maximum amount of torque from the motor (eg max throttle, or max pedal assist) is always going to result in the exact same amount of output from the motor.

The only difference is It's just going to result in a higher rate of acceleration in the lower gear ratio. Which is going to make it "feel" better, or feel easier on the motor.

That motor is still outputting its max output. That is still getting transformed by the chainring into linear tension force in the chain, it's still getting transformed back into rotational torque in the rear cassette. That is still getting transformed into linear force at the point where the tyre meets the ground.

The only caveat to that is if you lift or spin a wheel, or operate the motor outside of its rotational RPM window where it produces its rated torque, or if the battery/controller is limiting the input to the motor.

I sort of see your point, however max output of a motor has nothing to do with the force applied to a particular component it is a funtion of applied force required for a chosen outcome and the resistance to that outcome . Your confusing felt force with force applied In our case power wich is a funtion of gearing and force - weight, gravity, friction etc wich is resistance. This equals speed not force . When a motor is rated for torque it is a value derived from how much force is measured with 100 percent resistance to that force. It is measured direct from drive shafts twisting force against 100 percent return resistance . that full amount of force can only be applied on components in a locked real wheel with max throttle scenario. The millisecond that wheel starts rolling the felt force on components starts to reduce, and the result is speed. so if we chose the wrong gear for a particular desire, we may be asking for all of the power available at to much resistance and yes we can certainly destroy things with 160nm. I think the key is to use judgment in the components we chose and the way we utilize them with this beast. I like wheelies ...blaaaahha

 

[CaptainBobt]

I sort of see your point, however max output of a motor has nothing to do with the force applied to a particular component it is a funtion of applied force required for a chosen outcome and the resistance to that outcome . Your confusing felt force with force applied In our case power wich is a funtion of gearing and force - weight, gravity, friction etc wich is resistance. This equals speed not force . When a motor is rated for torque it is a value derived from how much force is measured with 100 percent resistance to that force. It is measured direct from drive shafts twisting force against 100 percent return resistance . that full amount of force can only be applied on components in a locked real wheel with max throttle scenario. The millisecond that wheel starts rolling the felt force on components starts to reduce, and the result is speed. so if we chose the wrong gear for a particular desire, we may be asking for all of the power available at to much resistance and yes we can certainly destroy things with 160nm. I think the key is to use judgment in the components we chose and the way we utilize them with this beast. I like wheelies ...blaaaahha

The fact is Max torque 160nm can only be applied to a cassette if there is exactly 160nm fighting back

 

[bram.biesiekierski]

The fact is Max torque 160nm can only be applied to a cassette if there is exactly 160nm fighting back

This is not true. Unless the gear ratio between the chainring and the cassette gear is 1 : 1.

But what i think your trying to say is that there needs to be resistance to the motor "fighting back" in order for the motor to work against??? Is that it???

Well, there will ALWAYS be resistence fighting back. Our bodies and our bikes have mass, around 25kgs for the bike, and in my case, a bit over 100kg for myself.

According to newtons second law of motion. In order to accelerate a mass, you need to apply a force. This is a basic physical concept. Infact its not a concept, its a law, and it is expressed as F=MA. This means in order to accelerate the mass of our bodies and bikes, we must apply a force. Accelerating our mass is the resistence "fighting back" againt the motor you speak of.

Just because a body and bike already has some velocity, it does not reduce the force needed to further accelerate it.

The other component of resistence "fighting back" against the motor is drag, this is made up of rolling resistince, tyre deformation, mechanical friction loss, wind/air resistance, all these type of losses.

The reason we cannot go infinitely fast, is because at some point, the force our motors (and legs) can output, is matched in equilibrium with the force of drag / resistence slowing us down.

I know with my bike, that's around 50km/h. That is the point where wind resistence and drag is equal to the power my motor can output. When the drag is equal to motor output, there is no more output left to be put into accelerating.

 

[bram.biesiekierski]

Think of this scenario.

You have 2 identical e22s. Both exact same drive train, gearing, wheels, etc etc. Both identical motors, both identical batteries. Both full charge. Everything same.

Then you have 1 rider who is 80kg. And the other rider is 100kg.

Then the riders hop on the bikes. They both select level 5 assist. And both simultaneously push the throttle to max.

Now, do you think that the bike motor with the 80kg rider is going to magically have less power or torque??? Or that the bike with the 100kg rider is magically going to have more power and more torque?

No. They both have exactly the same motor. They both have exactly the same rated outputs.

The difference is that the bike with the 80kg rider will simply accelerate faster. Thats it. The torque at the motor will be the same. The tension in the chain will be the same. The torque at the rear cassette will be the same. The torque at the rear wheel will be the same. The only difference is the 80kg rider/bike will accelerate faster.

 

[CaptainBobt]

This is not true. Unless the gear ratio between the chainring and the cassette gear is 1 : 1.

But what i think your trying to say is that there needs to be resistance to the motor "fighting back" in order for the motor to work against??? Is that it???

Well, there will ALWAYS be resistence fighting back. Our bodies and our bikes have mass, around 25kgs for the bike, and in my case, a bit over 100kg for myself.

According to newtons second law of motion. In order to accelerate a mass, you need to apply a force. This is a basic physical concept. Infact its not a concept, its a law, and it is expressed as F=MA. This means in order to accelerate the mass of our bodies and bikes, we must apply a force. Accelerating our mass is the resistence "fighting back" againt the motor you speak of.

Just because a body and bike already has some velocity, it does not reduce the force needed to further accelerate it.

Wbat im trying to say is that measured felt force on a cassete is a function of pulling by the motor and stopping by resistance. Yes you are correct when we are at a steady speed the amount of torque needed for any given desire is equal to the resistance fighting back otherwise we would either be slowing down or speeding up . So You are also correct that In order to accelerate you need to apply more force to achieve a new desired outcome until a new speed and equilibrium is acheived . This may or may not require all of the 160nm of torque from the motor and depends on the mechanical advantage the motor has thru gearing. I understand your point yes we can smash 160nm at the cassete but if the cassete has zero resitance appied to it the felt force will be minimal the amount of resistance fighting back onthe cassete is minimal . If your wanting to maintain the same speed and come upon a hill gravity creates more resistance thus requiring more power to maintain a certain speed. therefore more force from the motor to the casette with high resistance will increase torque felt on the motor and thus appied to the cassete.

So again You are also correct the force will be tranferred to the cassette from the motor however there must be resistance tranfered back thru the cassette in order for the cassete to feel that force . The motor will determine the amount of needed force thru gearing. This again may or may not be 160nm and is directly proportional to the amount of resistance. It is all determined by what force the motor needs to apply to do what we ask of it and what mechanical advantage we have provided for it. If I understand you correctly your saying that max torque is applied any time we ask for more power. That would be false. You mentioned lifting the wheel or reaching max motor speed is a caveat when in fact it is the same as resducing resistence or requiring minimal power. Max motor speed is just asking for something that it already senses has been achieved . What I'm trying to say is that the amount of tension or torque directly felt to the cassette will only reach 160nm if the cassette has that exact amount of resistance stopping it, even if its momentarily. and that exact amount of force moving it from the motor . So when we use say a 32t chainring we can easily apply max force to a cassette very quikly thru mechanical advantage however if there isnt 160nm fighting back aginst the cassete that amount of force is not applied. Yes if we deside we want max speed ie smallest rear gog at high resistance ie. A steep hill, we will achieve max torque on that cassette very easily. Because it will require all of the 160nm to reach what we asked. Wich is essentially max speed going up hill.. however if we are rolling down a hill where there is very little resistance a fraction of torque would be felt by the cassette even if the motor applies it . Make sense ..?

 

[bram.biesiekierski]

I sort of see your point, however max output of a motor has nothing to do with the force applied to a particular component it is a funtion of applied force required for a chosen outcome and the resistance to that outcome . Your confusing felt force with force applied In our case power wich is a funtion of gearing and force - weight, gravity, friction etc wich is resistance. This equals speed not force . When a motor is rated for torque it is a value derived from how much force is measured with 100 percent resistance to that force. It is measured direct from drive shafts twisting force against 100 percent return resistance . that full amount of force can only be applied on components in a locked real wheel with max throttle scenario. The millisecond that wheel starts rolling the felt force on components starts to reduce, and the result is speed. so if we chose the wrong gear for a particular desire, we may be asking for all of the power available at to much resistance and yes we can certainly destroy things with 160nm. I think the key is to use judgment in the components we chose and the way we utilize them with this beast. I like wheelies ...blaaaahha

There is alot of stuff in that paragraph that makes no sense. I'll try my best to decipher it.

Ok some basics.

Torque is rotational force. Often expressed as foot pounds (ft lb), or newton meters (nm). 1 ft lb is how much torque you would get if you put 1 pound of force, into a wheel with a radius of 1 foot, or a one pound of force into a lever that is 1 foot from the fulcrum. Likewise, 1 nm is how much torque you would get if you put 1n (~100gms) into a lever 1m from its fulcrum.

Power is torque x RPM. Torque and power are intrinsically linked. If you increase one, then the other also increases. Power is NOT a function of weight, gravity or friction.

Felt force - no idea what you mean here. Perhaps acceleration??? Acceleration is the rate of velocity change. When you apply a force to a mass, it will accelerate.

Motors are tested on a device known as a dynamometer, this is a machine that allows the motor to rotate, while simulating a load, (a resistence to the motor). This resistence (torque) opposing the motor is measured, and from there a power figure can calculated, as the RPM is simultaneously measured.

You notion that full torque can only be applied in a locked wheel scenario doesn't make any sense. How does an e-bike accelerate you if it can only create torque when the wheel is locked??? And likewise, your notion that the millisecond the wheel starts rotating, the "felt force" on components reduces doesn't make sense either. As I tried to explain above, we have mass, inorder to accelerate that mass, there needs to be force. The force required to further accelerate a mass doesn't magically reduce the millisecond it is in motion.

About the only thing that is coherent there, is that on these high powered bikes and fragile chain/gear drivetrains, we do need to be thoughtful in what components we choose.

 

[bram.biesiekierski]

Wbat im trying to say is that measured felt force on a cassete is a function of pulling by the motor and stopping by resistance. Yes you are correct when we are at a steady speed the amount of torque needed for any given desire is equal to the resistance fighting back otherwise we would either be slowing down or speeding up . So You are also correct that In order to accelerate you need to apply more force to achieve a new desired outcome until a new speed and equilibrium is acheived . This may or may not require all of the 160nm of torque from the motor and depends on the mechanical advantage the motor has thru gearing. I understand your point yes we can smash 160nm at the cassete but if the cassete has zero resitance appied to it the felt force will be minimal the amount of resistance fighting back onthe cassete is minimal . If your wanting to maintain the same speed and come upon a hill gravity creates more resistance thus requiring more power to maintain a certain speed. therefore more force from the motor to the casette with high resistance will increase torque felt on the motor and thus appied to the cassete.

So again You are also correct the force will be tranferred to the cassette from the motor however there must be resistance tranfered back thru the cassette in order for the cassete to feel that force . The motor will determine the amount of needed force thru gearing. This again may or may not be 160nm and is directly proportional to the amount of resistance. It is all determined by what force the motor needs to apply to do what we ask of it and what mechanical advantage we have provided for it. If I understand you correctly your saying that max torque is applied any time we ask for more power. That would be false. You mentioned lifting the wheel or reaching max motor speed is a caveat when in fact it is the same as resducing resistence or requiring minimal power. Max motor speed is just asking for something that it already senses has been achieved . What I'm trying to say is that the amount of tension or torque directly felt to the cassette will only reach 160nm if the cassette has that exact amount of resistance stopping it, even if its momentarily. and that exact amount of force moving it from the motor . So when we use say a 32t chainring we can easily apply max force to a cassette very quikly thru mechanical advantage however if there isnt 160nm fighting back aginst the cassete that amount of force is not applied. Yes if we deside we want max speed ie smallest rear gog at high resistance ie. A steep hill, we will achieve max torque on that cassette very easily. Because it will require all of the 160nm to reach what we asked. Wich is essentially max speed going up hill.. however if we are rolling down a hill where there is very little resistance a fraction of torque would be felt by the cassette even if the motor applies it . Make sense ..?

I think you are going about it back to front in your head. The motor is the source of the torque/power. This is where you must start in trying to understand whats happening. It seams you are thinking about this in back to front logic. You are thinking about it from the rear wheel forwards. Not from the motor back.

When you request power by either pushing the throttle, or request power via peddalling with peddle assist switched on. The motor begins generating torque. The motor doesn't know what gear ratio your in etc. It just starts putting force into rotating its output shaft (the chainring.)

This rotational force goes through the drivetrain, through a gear reduction or multiplication depending on what gear ratio you have selected. And then into the rear wheel, and ultimately begins accelerating you and the bike.

The motor generates torque dependent on how much you press the throttle, or what level pedal assist you have selected. You seem to be confused at this part. You seam to think the motor only generates as much torque as it takes to rotate the wheel, and no more. Where infact the motor generates only as much torque as you request (either via throttle or peddal assist level).

This motor torque ultimately starts rotaing the rear wheel. If the gear ratio selected is very high, or the rider is very heavy, or there's a steep hill, (what you call resistence) the amount the rear wheel accelerates is will be less. If the gear ratio is very pow, or the rider is light, or your going down hill, it won't change how much torque the motor makes. It's only going to change how much acceleration results from that torque.

I hope I explained that in a way you can wrap your head around

 

[CaptainBobt]

Think of this scenario.

You have 2 identical e22s. Both exact same drive train, gearing, wheels, etc etc. Both identical motors, both identical batteries. Both full charge. Everything same.

Then you have 1 rider who is 80kg. And the other rider is 100kg.

Then the riders hop on the bikes. They both select level 5 assist. And both simultaneously push the throttle to max.

Now, do you think that the bike motor with the 80kg rider is going to magically have less power or torque??? Or that the bike with the 100kg rider is magically going to have more power and more torque?

No. They both have exactly the same motor. They both have exactly the same rated outputs.

The difference is that the bike with the 80kg rider will simply accelerate faster. Thats it. The torque at the motor will be the same. The tension in the chain will be the same. The torque at the rear cassette will be the same. The torque at the rear wheel will be the same. The only difference is the 80kg rider/bike will accelerate faster.

Yes you are correct in your senario the torque at the rear wheel would be the same but your missing my point and proving my point at the same time in essence you saying exactly what I'm telling you. All I'm saying is felt force or torque i guess on the cassette is measured by the rsstance required to stop the force and the fat guy requires more for the same result thus putting more tension on the cassette . doesnt matter who accelerates faster in your scenario yes both riders are putting equal force on there chains but the lighter guy is faster his doesn't matter the fat guy is still trying to achieve the same result and will need more force to get there ..