D's RC Drive Kona DC1

[MitchJi]

Hi D,

Bear in mind how the motor transmission (chainline etc.) will interact with the suspension...............

Adding a second chain to a FS bike presents some complications.

One other thing i'd like to ask about - given that my system runs fine as is (maybe would like more top end, my motor struggles after 3rd) i keep coming back to wondering why i can mount two eno's at the crank with a custom arm?.

If you only need to reduce the resistance to pedaling (as opposed to getting a 3 speed chain ring, isolated from the motor) I think the easiest way to do that would probably be to add a second stage to Matt's drive, replace the large pulley Eno Combo with a solid pulley and put a 16t eno on the final output. You'd end up with something like:
first stage belt -> second stage #25 chain (up to about 4:1 I think) -> third stage 16t Eno to roughly a 40t chain ring.

That would totally solve the pedaling effort (you'd only be turning the third stage chain and the outside of the Eno). That should require less effort than pedaling a bike with the rear wheel raised.

You'd lose a few percent of efficiency but you could more than make that up by increasing the reduction and using a higher kv motor (an 8150 will work with your belt). A higher kv 8150 would give you substantially more power

I said probably depending on two issues:
1. It looks like, after checking Matt's drawing you could use your existing mount with a 2 stage MS drive and that the chain line would still be correct (ask Matt to be sure).

2. I think based on looking a Y's build that a folded 2 stage would probably fit using your existing mount.

A 3220 with 2 chains and a triple chain ring would have some obvious advantages. OTOH its going to be a lot more work to add a second chain.

Also in terms of noise (and if you dump your first stage and go with a single stage or go to a 3320 and replace the belt with #25 chain) I think:

• quietest - multiple stages with first stage belt
  
  louder (listening to Matt's builds I don't think its a big difference) - multiple stage with first stage #25 chain (required with a 3220)
  
  loudest (listening to Gary's 3220 build I think this will be a substantial difference)- single stage 3220

So even if you decide on a 3220 with a second chain to the rear hub I think you should consider keeping your MS drive as part of a two stage reduction system.

 

[deecanio]

Hi Mitch,

yes i know i have a lot of thinking to do but my mind is set on simpler design, adding another stage to my current setup isn't the answer, and the way you describe i would still be pushing the motor chain around needlessly.
I'll be going with the twin freewheel and extron at the rear for sure, but up front theres going to be a major change, i have a couple of problems, the suspension and chain growth on the motor chain and mounting (AGAIN) being the worst ones as you mention , but as ever i am optimistic that there is a way around it
we'll see what winter brings for 09/10 seaon

D

 

[AussieJester]

wont need reduction

Will you be selling the Mr R reduction drive Deec? if so let me know i might have a buyer for it

KiM

 

[GGoodrum]

right at the base of the seatpost where i originally planned, i wont have to worry about the foot as i wont need reduction and i will limit the suspension travel as not to hit, everyone will yell at me that it doesnt fit but i know it will.
failing that i'll try to mount under the bb or adapt the box to incorporate the motor even if it means redesigning the box and outing the esc and throttle board to an external box to make it happen

D

D I think you need to keep the first stage of Matt's drive in order to at least match the low-end torque I'm getting with my direct drive setup with the 3220. The reason is that you won't have the 3-speed hub's 1st gear reduction, which is 0.75:1. Right now I have a 94t sprocket on the rear and an 11t motor sprocket. 1st gear on the S-A hub would be like having a 125t sprocket on a regular hub, like you are using. Leaving Matt's 1st stage on there all you would have to do is move your existing 80T Extron sprocket to the back, attached to a "splined" Sickebike flanged ENO FW. The 11t still drives the 80t Extron but it is now in back, instead of on the front crank. You might need one or two chain guide/tensioners, to guide the #219 around the bottom bracket, but that is easy. A second 16T splined ENO would be driven by your 3-ring front dérailleur. This change alone would give you more low-end torque than you have right now, and this is still using your existing 3210. The beauty of this is that except for a simple adapter plate that will mate up the Extron with the 5-holed flanged ENO, whatever guides/tensioners that are required and a longer #219 chain, you already have everything you need, and you don't have to remount the motor. Later, if you still want even more power, you could switch to the 3220, but you would need to either use a version with the same kV as your 10-turn 3210 (135...), or change to a larger #219 drive sprocket, which would have the added benefit of being quieter.

-- Gary

 

[AussieJester]

I think Ds other concern was isolating the crank completely from the motor ? I might be wrong...But i believe his other concern is reducing
the pedal resistance. Ol' Deec couldnt quite follow the whole turn the chain rings with the motor not the crank shaft concept...BUT he professes to being PR0 at kicking a soccer ball to himself

KiM

 

[GGoodrum]

I think Ds other concern was isolating the crank completely from the motor ? I might be wrong...But i believe his other concern is reducing
the pedal resistance. Ol' Deec couldnt quite follow the whole turn the chain rings with the motor not the crank shaft concept...BUT he professes to being PR0 at kicking a soccer ball to himself

KiM

Actually, this includes total motor and pedal independence. It assumes, however that Luke/Miles/Thud/Mud/BigMoose/et al are successful in their efforts to achieve what is apparently doable by a nine-year old girl, which is to carve splines into ENO freewheels. I gave up trying to understand what is going on when even after watching the video of cute little Rachael three times, I still didn't get it.

Anyway, I'm assuming D will put two ENO on his standard hub, one that is attached to the Extron sprocket and the other that will be driven by his standard 3-speed front dérailleur setup, which he used to have on this bike. That still allows him to have three gears for pedaling, but now they are completely independent from the motor.

-- Gary

 

[12p3phPMDC]

Gary,

just think of the broach as a file with enourmous teeth on the edge.

The broach bushing just holds the broach in alignment.

The broach bushing fits the ID of whatever it is you want to broach.

The depth of the broach minus the depth of the slot in the broach bushing determines how much
material is removed on the first pass. On the second pass, you insert a shim in the bottom
of the broach bushing, effectively decreasing the depth of the broach bushing slot.

Does that help?

 

[AussieJester]

Gary you dont get what they are doing or how they are trying to do it?

KiM

 

[GGoodrum]

Gary,

just think of the broach as a file with enourmous teeth on the edge.

The broach bushing just holds the broach in alignment.

The broach bushing fits the ID of whatever it is you want to broach.

The depth of the broach minus the depth of the slot in the broach bushing determines how much
material is removed on the first pass. On the second pass, you insert a shim in the bottom
of the broach bushing, effectively decreasing the depth of the broach bushing slot.

Does that help?

Yes, the adding-the-shim step is what I was missing. That moves the "teeth" farther out each time, I get that. In the video, it is just done once, I gather.

Where I'm having trouble following is with the stuff Thud/Mud are talking about doing to make some kind of guide or tooling for Luke, and then the process Luke will use to actually do the work.

We don't need to clutter up D's thread with this stuff, so I'll ask my questions in the splined thread.

 

[Miles]

We don't need to clutter up D's thread with this stuff..............

Oooooh, I don't know.........

 

[deecanio]

it is all useful info to me so i don't mind a bit
i get what we're doing, but not the machining process to get it done, i should have paid more attention at college you'd never guess i'd had basic training on mills/lathes and shapers eh?
im doing exactly what Gary sais, twin eno's on the freewheel hub at the rear and a three speed crank up front, well, so far that's the plan, however i would prefer my gearing at the back and a single speed upfront to avoid complicated chain lines and mounting.
What i want to know is how are we getting on with delta/wye board? , really i want a much simpler setup, im impressed with the rc motors for sure, particularly the size of the motors and controllers, but having to have the reduction for their high rpm kinda negates the benefit of the small size of the motor itself imo.
now if we're talking dreamy world i'd want a motor similair in size to the 3210 but, capable of direct drive to the extron, best i can do is 11-92 i believe which isn't enough to get the low down torque so im a little stuck with decisions at the mo
i have considered a small agni but then i'd have to have a controller the size of a house brick.
so it seems i'm still with the rc setup at this point and at least a single stage reduction however this time around i'm not going to rush in as i usually do and just figure something out that works a treat, if that means i have to buy a new frame i will, i've had a look a good few but theres not much out there that fits the bill
still im bloddy good at soccer :lol:

D

 

[Ypedal]

Having the dual freewheel at the rear hub also means you ban back the bike up !!!....

One thing that i don't like about these chain drives gong thru the front cranks is taht backing up the bike forces the gear ratio inot reverse messing with the chain tensioners ( unless they are spring loaded vs starionary ) ..

 

[Miles]

now if we're talking dreamy world i'd want a motor similair in size to the 3210 but, capable of direct drive to the extron, best i can do is 11-92 i believe which isn't enough to get the low down torque so im a little stuck with decisions at the mo

Yup.

8.36:1 That will give you a motor speed of around 2500 rpm, which means that the 3210 will be stuck at about a third of its nominal power.

 

[AussieJester]

:
still im bloddy good at soccer :lol:

D

hehe you called it "Soccer"

Iwas just looking back for where you said you never would and saw some close ups of your reduction drive, i forgot you had the freewheel installed and the jackshaft lengthened...still i am VERY interested when you come too sell it Deec...Best of luck getting a direct drive setup...

KiM

 

[jmygann]

now if we're talking dreamy world i'd want a motor similair in size to the 3210 but, capable of direct drive to the extron, best i can do is 11-92 i believe which isn't enough to get the low down torque so im a little stuck with decisions at the mo

Yup.

8.36:1 That will give you a motor speed of around 2500 rpm, which means that the 3210 will be stuck at about a third of its nominal power.

Is that in first gear ? ... 20" tire ?

 

[deecanio]

Hi jmygann,

i'm not sure, i run a 24" rim but it's near as spit 26" with the knarly tyres

Yup.

8.36:1 That will give you a motor speed of around 2500 rpm, which means that the 3210 will be stuck at about a third of its nominal power.

not sure what you mean here Miles ?
im with you Y that having the power through the crank isn't ideal, although it isn't an accurate word in this context i like "synergy" - not the type that matches max motor rpm to max crank cadence though because i maintain that you can dial in power to match your cadence regardless of max motor speed if that makes sense.
what i need to do is to get my rc setup to match that of my puma with three rings upfront, the way this worked was beautiful, i had three pedal gears that i could use the bike with comfortably without the hub power, i could use the bike on hub power alone without the need for a freewheel crank, and even better i could use a combination of both at any ratio i chose which was just awesome, made for a fantastic ride and even though i was only running 6.6ah my batts lasted until i'd had enough anyway.
Sooooo, i guess my best option is to remain with the reduction i have (sorry Kim, it is yours when the time comes) go with the two eno's at the back and back to three upfront - this will give me all pedal/motor options back but im not sure as to the how the motor will work with the current reduction then onto a 11/92 setup - will i end up with goodd torque but no top end or vice versa?
This is where Gary's delta/wye board will come in hopefully so that i have three speed manual/two speed motor, however is this problem solvable by a new motor? i suspect not or Miles would already have suggested it to me so i'm dependant on a few things to satrt the rebuild, the modded enos, the delta/wye board, and figuring out how to remount the reduction unit in order to run a direct 219 chain to the extron whilst avoiding the fron deraileur, not easy, however IF this all comes together i will have achieved all my goals and reverted to the best setup i've had thus far, indeed i would still be on the puma had it been able to take a whacking - still things will be even baetter once i get this nailed as i will have the same system but with no unsprung weight or hub to bash.
I'm looking to a new frame as i said but i will try to use th stinker as everything is nearly there, hopefully Steve will help me figure things out, i do keep looking at the mongoose though like bikeraiders, however even with a new frame theres the issue of chain growth on a full susser decisions decisions

D

 

[Miles]

Yup.

8.36:1 That will give you a motor speed of around 2500 rpm, which means that the 3210 will be stuck at about a third of its nominal power.

not sure what you mean here Miles ?

I was referring to the 11t to 92t direct drive. It means that there's not enough reduction to get the torque that you need.

 

[AussieJester]

(sorry Kim, it is yours when the time comes)

No probs whatsoever Deec, when ever your done with it, looks like my mate Matt P is set on stripping his
1000watt cruiser and using the components from it in his MTB Project So the drive Unit i will keep for ME! Least he came
dropped this whole hub motor thing he was planing originally



I spotted the forks on Ebay FORTY BUCKS NEW cost Matt $AU100 delivered..He has done what I suggested to you
also Deec, 20in rim on the back with 3in tire (24in on front) so he can fit the motor in behind the seat post
like you wished too do orginally looks SICK IMHO.. WiLL be a another Pro-looking ride
when Matts finished with it, ashame hes trashing his crusier though i reeeally liked that bike...On the bright
side when he feels the need for a laid back ride again we get too see another custom build


Cheers Deec...

KiM

 

[deecanio]

i guess that answers my torque/top end question too Miles?
if i keep the current reduction with 11/92 direct drive im assuming i will have good torque but lousy top end? thats where i'd need Gary's delta wye

Hi Kim,

your buds bike does look ok on 20's actually, i can see the advantage with all that loverly seatpot with which to mount an recumpence drive, not rear suss to worry about either - the system i want would work amazingly on that bike but im a suck for front and rear travel.
those forks were an amazing bargain!!!

D

 

[GGoodrum]

i guess that answers my torque/top end question too Miles?
if i keep the current reduction with 11/92 direct drive im assuming i will have good torque but lousy top end? thats where i'd need Gary's delta wye

With your current setup, which I believe has a 17t/60t 1st stage (belt), 11t/80t to the crank, a 42t chainring back to 11t/22t/28t on the hub, you are getting a theoretical top speed in 1st of about 25 mph. This number is only important as a frame of reference for comparison. The lower this speed is, the more low-end torque you have available. The reason you aren't getting the range you'd like is because for the max torque you require on your typical runs, too much current through the motor is required. There are a couple ways to reduce this current. One would be to simply replace the 3210 with a 3220 that has the same kV. That would significantly reduce the current required to get the same torque level.

Another way to reduce the current is to increase the gearing. If you did nothing else but move the 80t Extron #219 sprocket to the hub, you would get a net increase in the gearing ratio by a factor of 1.5:1. That is because you are removing the 42t/28t stage which is in the opposite gearing "direction". With your present setup, your overall ratio between the motor and the hub (in 1st gear...) is 60t/17t x 80t/11t x 28t/42t = 17.11:1. If you move the 80t to the back, eliminating the 28t/42t stage, the overall ratio is increased to 25.67:1. This means your top theoretical speed is now about 17mph.

The problem with this is that since you have decoupled the motor drive from the pedals and the 3-speed dérailleur, the motor drive doesn't have the higher gears to get a higher top speed. This is where the delta-wye switching would help. In delta mode the kV goes up from 135 to 234, a factor of 1.73:1. This will bump your top speed up to about 30 mph.

My 7-turn 3220 (kV:97) setup has a direct 94t/11t ratio of 8.55:1, but since I'm using a 3-speed hub the total ratio in 1st gear is 11.71:1. With the smaller 20" wheels, this gives me a top speed of about 18 mph in 1st, 24 mph in 2nd and 34 mph in 3rd. Even in 2nd this setup has gobs of torque. This is why I know simply switching to a 3220 in your setup will help lower your amp draw. I get the same top speed in 2nd that you do in 1st, but to get the same torque, it will use a lot less current.

Getting back to your proposed new setup, I'm guessing you will want a bit more performance and increased range, and you could do that by simply coming closer to matching my 3220 setup in terms of gearing. Personally, I think mine has too much low-end torque, as I can't stay on it and give full power in first. Flips me right of on my butt. At some point I'm going to change my 11t motor sprocket to a 12t, which will bump the top speed in 1st to about 20 mph. This should also reduce the horrible racket my setup makes. That is the biggest problem with not having the belt drive 1st stage, it makes a horrible amount of noise, which is made worse by the small 11t sprocket.

Anyway, if you replaced your 3210 with the 3220 like I have, you will need to increase the size of the 11t drive sprocket. An 18t would give you a top speed in wye mode of about 20 mph, and about 35 in delta mode. This should do the trick.

-- Gary

 

[recumpence]

If D goes to a 3220, he will need to install a larger motor pulley. The pulley on his 3210 is adequate for the power that motor puts out. A 3220 will skip the belt. So, I would suggest going up on the motor pulley size to get taller gearing as well as more tooth coverage for higher torque handling.

I went through this with my recumbent.

Matt

 

[MitchJi]

Hi,

At some point I'm going to change my 11t motor sprocket to a 12t, which will bump the top speed in 1st to about 20 mph. This should also reduce the horrible racket my setup makes. That is the biggest problem with not having the belt drive 1st stage, it makes a horrible amount of noise, which is made worse by the small 11t sprocket.

Anyway, if you replaced your 3210 with the 3220 like I have, you will need to increase the size of the 11t drive sprocket. An 18t would give you a top speed in wye mode of about 20 mph, and about 35 in delta mode. This should do the trick.

-- Gary

Excellent explanation!

The main problem I see with the single stage is the noise.

If direct drive 3220 with an 18t drive sprocket (vs 11t) is comparable in noise to his belt drive 2 stage it would be a good setup for D.

Yes, the adding-the-shim step is what I was missing. That moves the "teeth" farther out each time, I get that. In the video, it is just done once, I gather.

Not missing the opportunity to add another OT post to D's thread I think the teeth length increases (each tooth on the broach is a little longer than the preceding tooth).

 

[GGoodrum]

If D goes to a 3220, he will need to install a larger motor pulley. The pulley on his 3210 is adequate for the power that motor puts out. A 3220 will skip the belt. So, I would suggest going up on the motor pulley size to get taller gearing as well as more tooth coverage for higher torque handling.

I went through this with my recumbent.

Matt

I agree, and if he went up to a 19t and changed the #219 drive sprocket to a 16t, it would be roughly the same gearing.

 

[recumpence]

Sounds good to me Gary.

Matt

 

[deecanio]

hey guys

thanks for all the input, i really appreciate it.
Just to add fuel to the fire i do have an idea to throw out there, recently i have been looking for a dh'er for pedal use only the reason being that i want to ride this winter and improve my general riding skills and also my ebike is only a seasonal machine.
After coming very lose to buying to £1100 pound Specialized big hit (lost by £50 on ebay) i stopped for a while to consider my options again and have come to the conclusion that i really need to have a long hard think about the next step.
I have the kona which i love but is not without it's build issues.
i want a pedal only bike to ride this winter.
Soooo, it occurs to me that rather spend a lot of money on a new dh'er i COULD revert my stinky to pedal only with ease and instead buy a new bike for a new setup
of course this opens a whole can of worms as to what to go for but the more i think about it the more sense it makes.
The current kit i have could be easily removed and used for the next effort, and the stinky could be pedal only in a day or two which would be nice as it's already raining daily and unlikely that i'll get out on it with power now anyway.
Of course this means we are totally free to design from the ground up again only this time we know what we to implement and which frame will be ideally suited?
twin 3220's on a mongoose anyone?



D