Dave's 80:1 RC mid drive kit build log

[Hillhater]

Has anybody tried a true Sine wave controller on this yet ?..just to see how much quieter it makes it !
Whilst i get Dave's liking for the "gasser" simulation sound, many of us will need this to be very stealthy if we want to use it on road.

 

[macribs]

It seems the most common controller to run these Astro motors are regular RC ESC. Have not seen those in sine wave.
It seems Adaptto and other high E-rpm's controllers will work with those Astro motors. I hope someone will test and share.

 

[district9prawn]

Has anybody tried a true Sine wave controller on this yet ?..just to see how much quieter it makes it !
Whilst i get Dave's liking for the "gasser" simulation sound, many of us will need this to be very stealthy if we want to use it on road.

I'm running mine on the grin/ASI FOC controller. While it makes a minor difference in volume, the difference is more in the quality of the sound. Smoother and not as harsh. In any case, astros are not quiet motors. Just the motor with no reduction spinning at full speed is not something most would consider quiet.

 

[tangentdave]

Design updates:

-rubber motor mounts eliminate any frame resonance or vibrations and dampen high RPM gear noise. The drive is comparatively silent now except at full RPM

-new aluminum mount plates are stiffer and lighter than steel and offer customization advantages. Improved wrap-around housing mount eliminates torque twist which means no frame clamping is needed. Torque is transferred to the bike frame via polyurethane cushion and the drive is held against the frame using adjustable metal straps that can fit any shape frame tube.

-improved chainline. The motor chain has been moved to the inside sprocket position to allow the use of larger bike chainrings and improve torque transfer efficiency. The ISIS 128mm spindle is standard for 3205 and 3210 motors; the 148mm ISIS spindle is needed for 3215 and 3220 motors.

-custom molded oil seals improve service life.

-new ESC mount keeps things clean while doubling as an improved heat sink for the HV80.

-revised chain tensioner captures the ball bearing pivot and spring within the delrin slider to protect against the elements and provide a cleaner profile.

Better pics and videos coming this week as the production units are made. These will be clear anodized by request.

Customer updates:

The initial units are performing well with no issues reported. The majority of the drives are being used for commuting with customers electing to use small capacity packs (5Ah) sized for the daily ride. Every rider has elected to increase the size of the front chainring to match the torque output of the Tangent drive, 38-44t sprockets are common as are 29" wheels. One customer has over 1000kms on his unit and reports no sign of wear on the gear faces We will be switching to the high-output White Industries flanged freewheel from Sick Bike Parts to make use of sealed bearings and better match the quality of the rest of the kit.

-dave

 

[StinkyGoalieGuy]

Design updates:

-rubber motor mounts eliminate any frame resonance or vibrations and dampen high RPM gear noise. The drive is near silent now except at full RPM

This is huge. The noise is the only thing keeping me from jumping all over this. Can you post a video so we can hear what this sounds like now?

 

[tangentdave]

Most definitely I will. Cutting production parts this week, I'll work a quick video in there.

 

[Archer]

It seems the most common controller to run these Astro motors are regular RC ESC. Have not seen those in sine wave.
It seems Adaptto and other high E-rpm's controllers will work with those Astro motors. I hope someone will test and share.

So what would it take to make the Tangent sine wave compatible? Is it something that needs done both on the Tangent and Adaptto sides,or just on one side?

Thanx Tim.

 

[Ralith]

So what would it take to make the Tangent sine wave compatible? Is it something that needs done both on the Tangent and Adaptto sides,or just on one side?

If a given sine wave controller can handle an Astro motor, it should just be a matter of configuring the controller appropriately. The only way in which the Ascent kit is at all sensitive to that is that it normally comes with a RC ESC instead.

 

[jk1]

tangentdave wroteesign updates:

-rubber motor mounts eliminate any frame resonance or vibrations and dampen high RPM gear noise. The drive is near silent now except at full RPM




This is huge. The noise is the only thing keeping me from jumping all over this. Can you post a video so we can hear what this sounds like now?

I would imagine most of the noise comes from the metal gears in the gearbox not the mounting unless their was some type of resonance accentuating it?

 

[tangentdave]

I would imagine most of the noise comes from the metal gears in the gearbox not the mounting unless their was some type of resonance accentuating it?

The gear noise is due to straight cut gears. The rubber mounts isolate this vibration (noise) from the bike frame and dampen the housing in general. It's not hub motor creepy silent but def quieter than a cyclone setup and when not at max revs, it's about on par with a noisy bicycle.

-dave

 

[jk1]

def quieter than a cyclone setup

How did you measure that as some people have commented it seems way louder on the videos? as this motor has higher RPM than cyclone? and usually more RPM means more noise as well.

 

[macribs]

The gear noise is due to straight cut gears. The rubber mounts isolate this vibration (noise) from the bike frame and dampen the housing in general. It's not hub motor creepy silent but def quieter than a cyclone setup and when not at max revs, it's about on par with a noisy bicycle.

-dave

Would it be possible to use helical gear rather then straight cut? Should do wonder for the noise I think?
Then again, with your new mounting and isolation of vibration there might not even be much noise at all anymore.

I like very much where Tangent Drive is going. Keep up the good work Dave!

 

[tangentdave]

Mr. Macribs, helical gears are quieter but they also produce side loading which greatly complicates bearing choice and housing design. The cycloidal arrangement doesn't lend itself well to a helical profile either. Each of the gears inside the drive have several teeth in contact with the ring gear so strength is not an issue and there are still more ways to quiet the unit. Straight cut is the way to go design wise- the advantages outweigh the negatives.

-dave

 

[macribs]

Yeah I kind of figured you had put thoughts into this design. I must say they way you have packaged it all in a small volume light weight package is impressive. The advantages far outweigh (pun intended) what little [strike]noise[/strike] sound is left in the drive.

 

[tangentdave]

Transmissions built for racing are usually straight cut gears for the same reasons. The higher the torque the higher the side loading on helical gears, the larger the bearings need to be, the thicker the housing needs to be...

 

[Dogboy1200]

Have you ever seen a Traction Planetary. Rotrex uses them in their superchargers http://www.rotrex.com/Home/Technology/Product_Concept. They use the same special fluid most CVT car transmissions use. This fluid is a lubricant until you squeeze it between 2 hard surfaces, then its sticky. So a Traction Planetary uses rollers and the fluid makes them act like gears. The Traction Planetary might actually be easier to build than a gear planetary. Looks like you could machine the Pinion, Planetaries and ring gear to be an interference fit then heat the ring gear to get it together. Once the ring gear cools the components are preloaded providing the force needed to make the fluid work. If you look at the little movie on the Rotrex site It looks to me like they support the pinion with bearings. The Planetaries and ring gear are supported by the pinion. The planetaries have bearings only to interface with the planetary carrier.

 

[Warren]

Dogboy1200,

"Have you ever seen a Traction Planetary."

Somebody produced a small 250 watt, toothless, friction planetary drive, front hub motor that Schwinn used in their Campus e-assist eight years ago. They failed. The hardened and ground ring "gears" would split from the pressure.

http://www.treehugger.com/bikes/schwinns-electric-bikes-now-available.html

 

[Nathan]

small volume light weight package is impressive

It doesn't look like its breaking much ground on the volume and weight compared to the existing 48v 1680w cyclone kit by those specs, pretty much the same weight and similar continuous power and probably noisier due to higher RPM so I can't see much advantages at that expensive price point nearly 3 times the price of the cyclone. Now if you could make that same gearbox with quiet plastic gears that would be better.

 

[tangentdave]

Torque is the difference; wattage ratings are misleading. Torque moves you, wattage heats things up. According to the info I find, the cyclone gearbox is 9:1 reduction, the secondary chain is prob 11:40 so 4:1 reduction. That means overall the cyclone is 9x4=36:1. This means the motor needs a slow wind, it still outruns the pedal cadence quickly and needs more current to produce the same torque as Tangent. In other words, at 1680W, all things equal, Tangent will make double the torque of a cyclone. And we haven't even started using the 3215 or 3220 yet, and the internal 40:1 reduction is just about right to drive the rear cassette directly...

That said, it is a cheap commoditized Chinese product, and if that's what you're looking for, a cyclone setup is prob your best bet. AFT, E-go and Kranked all picked it as the best setup available to them and it works pretty well.


-dave

 

[macribs]

small volume light weight package is impressive

It doesn't look like its breaking much ground on the volume and weight compared to the existing 48v 1680w cyclone kit by those specs, pretty much the same weight and similar continuous power and probably noisier due to higher RPM so I can't see much advantages at that expensive price point nearly 3 times the price of the cyclone. Now if you could make that same gearbox with quiet plastic gears that would be better.

Well imagine using an Astro 3220 rather then then 3215, or the 3110........much more continuous power and much more peak power. Yet on par or better then other kits when it comes to size and weight. And did I mention 80:1 ratio? Steep hills will not stop you anymore. Traction will, or lack of traction

 

[aCeMadMod]

cyclone setup is prob your best bet. AFT, E-go they both sill Suck. you need to mod cyclone it your self to make it work alot bettter.

sorry i sill waiting for bearing for my frame and more welding it kill me . not to be test dave drive. Yes it a must the kit need to the new upgraded white freewheel dual bear . Dave's stock freewheel sorry it suck. my it dieing very fast . and than use my moded cyclone motor, by all cyclone motor it made by headline motors.



dave you need to add magnet traps . inside the your gearbox. it help alot for life and ez to clear, pace all

 

[Nathan]

Well imagine using an Astro 3220 rather then then 3215, or the 3110........much more continuous power and much more peak power. Yet on par or better then other kits when it comes to size and weight.

Yes those Bigger more expensive motors would have a lot more power but they would also be heavier and you need a stronger ESC and I don't think the brackets and the rest of the kit have been designed for those higher power levels as well... So we are only comparing the motor that most people use now as that was seems to work.

, Tangent will make double the torque of a cyclone. And we haven't even started using the 3215 or 3220 yet, and the internal 40:1 reduction is just about right to drive the rear cassette directly...

If two motors have the same power how can one make double the torque ? the only way for that is to have half the KV or double 2:1 gear reduction but the tangent gear reduction is not double the cyclone ? 40:1 Tangent vs 36:1 Cyclone gear reduction and KV is similar around 150kv ?
So this cannot be true, if this was true to have double the crank torque it would also means half the crank rpm and half the bike top speed .

 

[tangentdave]

Tangent uses 80:1 between the motor and crank.

Nathan you're right about the kV tradeoffs in electric motors. Let me revise my statement and say that for a given current input Tangent will make more torque than cyclone due to the reduction. Spinning the crankset at 250RPM seems to be a negative for most riders from what I gather, so to get the same torque (which is acceleration) from the cyclone, more current is required.

The reduction also provides various design advantages (smaller sprockets for instance), shorter phase currents (motor moves faster=tiny electronics) and the gearbox design is very robust and seems to be quite efficient (based on mileage vs Ah; need to measure for realz). Does anybody have kV and kT specs for the cyclone motors?

The 3220 is about 1.5lbs heavier than a 3210, not bad for double the current capacity.

 

[Ralith]

So that's why Castle Creations ESCs are so tiny compared to conventional ebike controllers! I was wondering.

Does that mean it might be safe to use a "conventional" bulky controller such as the Grin Tech Phaserunner at higher-than-rated continuous power, if those ratings were made with low-RPM motors in mind?

 

[macribs]

Yes those Bigger more expensive motors would have a lot more power but they would also be heavier and you need a stronger ESC and I don't think the brackets and the rest of the kit have been designed for those higher power levels as well... So we are only comparing the motor that most people use now as that was seems to work.

¨


Are you really concerned about an extra 1.5 lbs as long as you double the power? I would not be. I could drop that weight in 5 days
Yes bigger controller will be needed for 3220 motor, but again you have to see that cost in context with the extra power gain from 3220.

I think that there are things happening in some far away basement somewhere, so we will soon learn and see how a 3220 motor work with the drive.
I am confident that will be a sweet match.