A lot of noob questions - Converting a MTB

[Byte]

Hi Endless-Sphere members

I'm kinda new on this forum, so I'll introduce myself first. I'm Patrick, 16 years old, living in the Netherlands and my hobby's are: playing soccer, rc-cars and hopefully I'll have a new one soon: E-Bike's I discovered this forum by browsing through YouTube, where I met AussieJester, he referred me to this forum. There's many useful information on here, I'm glad I met AussieJester and by him this forum.
As I said before; one of my hobby's are RC-Cars, and that is also the reason I came with the idea of converting my bike to brushless. They almost work the same electronically, except the E-Bike's don't have a receiver.
Anyway, I've got an old rusty Mountain bike, which I want to convert. I don't know if the bike is a high-quality one, probably not. I've googled the name of the MTB; "GTX200", but I couldn't find the MTB. Maybe someone knows the brand of this thing, and knows if this is a cheap Made in China one, or a durable one?
Some pictures of my MTB:

I want to have a E-Bike with a lot of torque, topspeed should be about 60KMH (37MPH). I think I'll use these electronics:
Motor: Turnigy 80-100-B 130Kv Brushless Outrunner
ESC: Castle Creations Phoenix HV110
Battery: Zippy Flightmax 6S 5000mAh 30C (2 of them, wired in series -> 12S, 44.4V)
Throttle: Still not sure how to do this...
What do you think about this? Will this work for me?
For the throttle; what do you guys recommend? I saw some Twist Throttle's on Electricscooterparts.com, some people on this forum are using these. Which one should i use? They've got "Hall-Effect Throttles", "On/Off Throttles" and "5k Ohm Throttles". As said, I'm new to this side of electronics, so I really don't know which one to use, or which are better etc.


Some things about the drivetrain:
- I'm still not sure where I'll mount the motor, LiPo's and ESC, or how to get the rear wheel moving, but one thing I definitely do know: I want to be able to pedal On the forum I saw that some people have been using an extra sprocket on the otherside of the wheel, I think I'll do the same with my bike. I'm still not sure how I'll get the sprocket mounted on there, maybe some members got some pictures of how they did it? A picture of what I mean:

Or does somebody know a better solution?
- Of course I have to make a reduction unit, I'll make something like this (picture from forum member: Mud2005):

- Why does almost everyone use belt driven from motor to shaft, and from shaft to wheel chain driven? Wouldn't it be easier to use normal gears from motor to shaft?
- Where do you buy chains, belts, sprockets, freewheels, shafts etc.? Does someone have a link of a good online shop?

Some things about "cogging":
- I've read on the forum that many people have problems with sensorless motors, they don't startup good. Is it really so annoying? Is there many cogging? (In the "RC-World" it's called cogging, I forgot how you guys name it here on the forum ) Does someone maybe have a vid about it? My RC-cars also got cogging, but it's nearly nothing. Did someone already added a bunch of caps to the ESC, if so, did that help loosing the cogging?

A lot of questions, it would be great if you could answer these And sorry for my English, it isn't 100% perfect... if you don't understand something; just ask, and I'll try to explain what I mean.


- Patrick

 

[vanilla ice]

Maybe plan on paralleling 2 or 3 packs for some decent range. The rough start up problems hopefully will be gone when somebody figures out the easiest way to get sensors on these motors. That would also go a ways in helping with controller and throttle selection. You cannot use regular ebike throttles with an RC setup unless you adapt them to work. Extra components, extra money.. From what I've read the smaller RC controllers tend to blow, so go for one with a big amp rating.

 

[Byte]

Maybe plan on paralleling 2 or 3 packs for some decent range. The rough start up problems hopefully will be gone when somebody figures out the easiest way to get sensors on these motors. That would also go a ways in helping with controller and throttle selection. You cannot use regular ebike throttles with an RC setup unless you adapt them to work. Extra components, extra money.. From what I've read the smaller RC controllers tend to blow, so go for one with a big amp rating.

Thank you for your reply. What do you think the range will be? The LiPo's are expensive, so I'll start with 2*6S in series, after some time I'll buy some more for parallel. And when giving throttle at a start up, will the motor only cog for a very little time (0.5 sec or something like that?) or will it just continue cogging? So is it really necessary to pedal at the start?
Hmm.. I thought I had read somewhere on the forum that someone used an regular E-Bike throttle without modification, but I probably misread then.
Do you think 110A is not enough? I'll add some extra caps, and gear the bike low so the amp rating won't be too high I think.

 

[wasp]

using the 80% rule a 5ah lipo will only have 4ah(80%)....also 1 mile per ah(no pedaling) so 4 mile range
as for lipo being costly hobbyking has them for like 50 bucks each(20c)
so running 4 or 6 would give you much better range and power to spare
as for adding a sprocket on the otherside there are hubs out there with a left sprocket
my schwinn has one and you could probably find one...hell canadian tire would probably sell you a entire wheel
i have no ideal were you live but like i said i have one and could find another
nice bike btw full susp and lots of room in triangle
wasp

 

[vanilla ice]

For the throttle some people are using R/C test boxes with the pot on them. Or there are the Throttlizers, nice piece but not for the budget builds I don't think.

 

[Thud]

Byte,
Welcome to the forum. I wonder how many members AJ has steered this way.....
Here is a link to help you with a throttle build.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=12196&start=0
Notice the battery eliminator & sheilding for RF interferance.
On my set up I did not remove the 5k pot from the board, I just soldered onto the lugs of the 5k pot so it parralels the Magura (or other 5k ohm controller). Just be sure you can't bump the knob & go into cruze controll mode accidentaly)

The motor you choose is more than enough to make your goal (over kill IMHO)
I would look at the 63-74
http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7870&Product_Name=TGY_AerodriveXp_SK_Series_63-74_170Kv_/_3250W

(I am running a 50-65-380 on a BMX & it is not over burdend with light gearing)
The "cogging" you refer to during start up is actualy low speed auto syncronation isssues these style of controllers exihbit while trying to accilerate under heavy loads. The Castle creations are the best choice for this application. I have turnigy & CC units. both will lose sync if pushed hard & battery voltage get low but the castle is noticebly superior in maintainng sync performance
given you are starting with limited battery power (5AH) I strongly recomend you shoot for a lower top speed gearing. I would gear to match the fastest you can pedal in a 100 meter sprint(18-23 MPH?) this will ease the strain on the batteries & extdend your range dramaticly with only 5AH.
I am a fan of this method of drive:
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=13862
parts are cheap & it is super simple. this will reduce the gearing options for pedaling but I am sure your local bike mechanic/bike slavage yard has chain rings & freewheels to re-gear to the desired speeds.
We use the Belt systems in the reduction units to make it as quiet as possible. Watch a few videos of rc reduction units in action & you will hear the electric motor whine & noise inhearant in these set ups. every litle bit we can do to reduce the noise is a plus.

Hope I have helped. Ask any questions regarding gearing & set ups & someone will pitch in.

Q-are those 24" or 26" wheels? (507mm/590mm)
good Luck

 

[amberwolf]

Regarding adding the sprocket to the left side, there are quite a few ways. One that I've considered is from Eric Peltzer's ebike:
http://peltzer.net/ebike/
http://peltzer.net/ebike/ebike59.jpg

If you change the rear hub for one that's got the disk brake boltholes on the left side, it's even easier.

 

[mwkeefer]

You do have to admire Erics build... it's elegant in it's own way.

I would watch those front forks - the rusted MTN bike may not be a good and sturdy platform for an eBike.

-Mike

 

[Mark_A_W]

I think it's a good frame for an ebike.

Dual suspension, but with room for batteries/drive system.


The twist shifter may be useful (fit the rear shifter to the LH side, throttle on RH side and ditch the front shifter) .


Fit a 1 1/8" threadless headset to the frame....and throw the rest of the bike away.

 

[Kevinator]

Here's some other resources for a LHD hubs:

Chinese scooter hub; 36H You'll need to pull out the axle, flip it around and pup it back into the hub. That will allow a 7 spd freewheel on the right and single speed on the left.
http://cgi.ebay.com/bicycle-Motorized-BIKE-GAS-ENGINE-40-T-freewheel-Axle_W0QQitemZ150396539185QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item2304551131

Staton hub for chain drive; 28H, 32H, 36H, 48H, I think this one can take up to a 8-9spd freewheel on the right, single speed on the left.
http://www.staton-inc.com/Details.asp?ProductID=2769

 

[Kevinator]

oh i forgot to mention that I have a bike that's similar in design. Its a typical generic made-in-china bike branded as a Jeep Cherokee TSI

 

[AussieJester]

G'day again Byte

Firstly the lipos...go with 4 not two buddy paralle each pair the series the two pairs 44v10ah setup same as Timma has in his Norco build ..Thuds link to the throttle building using a servo tester is the cheap way you could also go down a similar route to me and by a purpose built throtle interface. They are 100 bucks, benefit here is programmability and the inclusion of a BEC to power your Hv110...ES member evlogic? i believe sells the digital version throtliser and ecther the analogue version. After using mr Fecthers i would suggest the throtleiser as you need to add resistors and caps to get Fecthers 'tuned in' properly apparently the digital version is alot more user friendly...soz Mr Fecther Buy a Magura throttle also Recumpence sells these (author of the throttle build thread) If you want a Turnigy like i am using Hobby City JUST yesterday go stock in bad news they only had 3 of the 130kv motors 29 of the 180kv...oops make that 28 i bought one last night hehee...As for your sprocket setup. new way some of the fellas are going is broaching freewheels to fit on sram hubs, one for pedal and one for motor, if you use a multi speed sram hub also gives you gearing option. Contact Liveforphysics for the broaching if you wish to go this way.

Best of luck mate

KiM

p.s where in The Netherlands are you matey? my ex-missus is from Bladel near Eindhoven.

 

[Byte]

Wow! A lot of replies, with many useful information

using the 80% rule a 5ah lipo will only have 4ah(80%)....also 1 mile per ah(no pedaling) so 4 mile range
as for lipo being costly hobbyking has them for like 50 bucks each(20c)
so running 4 or 6 would give you much better range and power to spare
as for adding a sprocket on the otherside there are hubs out there with a left sprocket
my schwinn has one and you could probably find one...hell canadian tire would probably sell you a entire wheel
i have no ideal were you live but like i said i have one and could find another
nice bike btw full susp and lots of room in triangle
wasp

Hmm... now many members said that paralleling 2 LiPo's would be better I think I'll do that.

Byte,
Welcome to the forum. I wonder how many members AJ has steered this way.....
Here is a link to help you with a throttle build.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=12196&start=0
Notice the battery eliminator & sheilding for RF interferance.
On my set up I did not remove the 5k pot from the board, I just soldered onto the lugs of the 5k pot so it parralels the Magura (or other 5k ohm controller). Just be sure you can't bump the knob & go into cruze controll mode accidentaly)

The motor you choose is more than enough to make your goal (over kill IMHO)
I would look at the 63-74
http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7870&Product_Name=TGY_AerodriveXp_SK_Series_63-74_170Kv_/_3250W

(I am running a 50-65-380 on a BMX & it is not over burdend with light gearing)
The "cogging" you refer to during start up is actualy low speed auto syncronation isssues these style of controllers exihbit while trying to accilerate under heavy loads. The Castle creations are the best choice for this application. I have turnigy & CC units. both will lose sync if pushed hard & battery voltage get low but the castle is noticebly superior in maintainng sync performance
given you are starting with limited battery power (5AH) I strongly recomend you shoot for a lower top speed gearing. I would gear to match the fastest you can pedal in a 100 meter sprint(18-23 MPH?) this will ease the strain on the batteries & extdend your range dramaticly with only 5AH.
I am a fan of this method of drive:
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=13862
parts are cheap & it is super simple. this will reduce the gearing options for pedaling but I am sure your local bike mechanic/bike slavage yard has chain rings & freewheels to re-gear to the desired speeds.
We use the Belt systems in the reduction units to make it as quiet as possible. Watch a few videos of rc reduction units in action & you will hear the electric motor whine & noise inhearant in these set ups. every litle bit we can do to reduce the noise is a plus.

Hope I have helped. Ask any questions regarding gearing & set ups & someone will pitch in.

Q-are those 24" or 26" wheels? (507mm/590mm)
good Luck

Many thanks for this awesome reply! The link to the throttle is a great and cheap solution, I think I'll do that. For that I only have to buy a Twist throttle and a servo tester, I think I've a HV UBEC laying around somewhere.

I might change the motor, as you're probably right that the one I stated above is overkill The one you mention; "63-74 170Kv", is rated for 10S, and I want to use 12S, it also has some negative reviews. Don't you think this motor will get too hot after some driving time? On the otherside; the one I mentioned, is overkill, but I think it won't get hot, and it will have a lot of torque (which I like).

Did you experimented with extra caps to the ESC? I've seen some people using extra caps to their ESC in RC's and they said the "cogging" almost disappeared. This should be the same with bikes. Aren't here people on the forum who added a bunch of caps to the ESC and noticed a (big) difference on their bikes?

Thank you for the link of the driveline method, it looks good, I'll consider that one. I will take the rear wheel of first, to see how it really looks over there, after that I'll make a decision of which method I'll choose.

Ah ok! That sounds logical, so I'll also use a belt driven system.
As the bike isn't here right now (it's by my dad) I can't measure the diameter of the wheels, I'm sorry.

Many thanks for your reply, it helps me A LOT!

Regarding adding the sprocket to the left side, there are quite a few ways. One that I've considered is from Eric Peltzer's ebike:
http://peltzer.net/ebike/
http://peltzer.net/ebike/ebike59.jpg

If you change the rear hub for one that's got the disk brake boltholes on the left side, it's even easier.

Thank you for the links, my first thought was also something like that. I'll also consider this one of course

You do have to admire Erics build... it's elegant in it's own way.

I would watch those front forks - the rusted MTN bike may not be a good and sturdy platform for an eBike.

-Mike

.

Who's Eric?
It's only light rust on the shocks, you can get it of easily with a bit of sanding paper I think.

I think it's a good frame for an ebike.

Dual suspension, but with room for batteries/drive system.


The twist shifter may be useful (fit the rear shifter to the LH side, throttle on RH side and ditch the front shifter) .


Fit a 1 1/8" threadless headset to the frame....and throw the rest of the bike away.

Hmm, that's a good idea! I think I'll do that, as the bigger gearing changes are made with the left shifter. Normally when biking I also don't use the right one, only the left one.

Here's some other resources for a LHD hubs:

Chinese scooter hub; 36H You'll need to pull out the axle, flip it around and pup it back into the hub. That will allow a 7 spd freewheel on the right and single speed on the left.
http://cgi.ebay.com/bicycle-Motorized-BIKE-GAS-ENGINE-40-T-freewheel-Axle_W0QQitemZ150396539185QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item2304551131

Staton hub for chain drive; 28H, 32H, 36H, 48H, I think this one can take up to a 8-9spd freewheel on the right, single speed on the left.
http://www.staton-inc.com/Details.asp?ProductID=2769

Thank you for the two links. The second one looks very nice, but also very expensive. First I'll look how the hub on my bike looks, and maybe how I can mount a sprocket on there. If there isn't a way to do it cheap, then I'll consider this one.

oh i forgot to mention that I have a bike that's similar in design. Its a typical generic made-in-china bike branded as a Jeep Cherokee TSI

The bike indeed looks almost the same, but it does has some extras mine hasn't got. I don't think it's the same one, thank you for your reply anyway

G'day again Byte

Firstly the lipos...go with 4 not two buddy paralle each pair the series the two pairs 44v10ah setup same as Timma has in his Norco build ..Thuds link to the throttle building using a servo tester is the cheap way you could also go down a similar route to me and by a purpose built throtle interface. They are 100 bucks, benefit here is programmability and the inclusion of a BEC to power your Hv110...ES member evlogic? i believe sells the digital version throtliser and ecther the analogue version. After using mr Fecthers i would suggest the throtleiser as you need to add resistors and caps to get Fecthers 'tuned in' properly apparently the digital version is alot more user friendly...soz Mr Fecther Buy a Magura throttle also Recumpence sells these (author of the throttle build thread) If you want a Turnigy like i am using Hobby City JUST yesterday go stock in bad news they only had 3 of the 130kv motors 29 of the 180kv...oops make that 28 i bought one last night hehee...As for your sprocket setup. new way some of the fellas are going is broaching freewheels to fit on sram hubs, one for pedal and one for motor, if you use a multi speed sram hub also gives you gearing option. Contact Liveforphysics for the broaching if you wish to go this way.

Best of luck mate

KiM

p.s where in The Netherlands are you matey? my ex-missus is from Bladel near Eindhoven.

Hi Kim!

Hehe you're the third (Or even fourth) who says I should go with 2 LiPo's in series and 2 in parallel, so I'll do that. Then I'll buy the 6S 5000mAh 20C for $50 each.I really like the link thuds gave me, so I'll use that idea.
I'm still not sure how I'll make the driveline, as I said in this post before: I'll look how it looks on my bike right now, and if it's possible to go with a cheap solution.
I live in Venlo, it's not far away from Bladel, about 70km (40 mile)




Many many thanks for the replys from all of you!

 

[Mark_A_W]

I think you got what I said about the shifters backwards.


You will not need the front derailleur, particularly if you are driving through the chain (can't change that one under load AT ALL).


So you take the rear twist shifter (normally right hand), and fit it upside down on the LH side.


Remove the front shifter completely (you will still need the front derailleur as a chainguide).

 

[gwhy!]

I might change the motor, as you're probably right that the one I stated above is overkill The one you mention; "63-74 170Kv", is rated for 10S, and I want to use 12S, it also has some negative reviews. Don't you think this motor will get too hot after some driving time? On the otherside; the one I mentioned, is overkill, but I think it won't get hot, and it will have a lot of torque (which I like).

Hi Byte,
I am using one of these motors on 12s and its fine , The bigger one actually gets hotter ( I also have one of these ).

 

[Thud]

Your very welcome Byte,
some follow ups:

"63-74 170Kv", is rated for 10S,

these motors are able to handle extra voltage with ease. A better choice still would be this motor:
http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5144&Product_Name=TGY_63-54-A_250Kv_Brushless_Outrunner_(Eq._52-20)
I have one but have not run it yet. It is a newer design & has a "skirt" bearing for much better support.
your original choice is fine also....if you are convinced to get 30+mph then your 1st choice is prolly best.

ADD CAPACITORS to any RC controllers you intend to use for driving a bicycle. another tip: keep the wires from the battery to the controller as short as possible. the wires to the motor are not nearly as sensitive. here is a link with a lot of details
http://endless-sphere.com/forums/viewtopic.php?f=28&t=7504&hilit=castle+controllers+add+caps
cogging will not be an issue for a bicycle. I allways recomend to "freewheel" the motor system so you can pedal without spinning the motor.

definatly parralell the batterys when your budget allows. Added capacity will not sag voltage under high loads as mutch & will make all the batteries happeir(& you too :lol: )
good Luck & keep us posted on your coming build.

 

[Byte]

Your very welcome Byte,
some follow ups:

"63-74 170Kv", is rated for 10S,

these motors are able to handle extra voltage with ease. A better choice still would be this motor:
http://hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5144&Product_Name=TGY_63-54-A_250Kv_Brushless_Outrunner_(Eq._52-20)
I have one but have not run it yet. It is a newer design & has a "skirt" bearing for much better support.
your original choice is fine also....if you are convinced to get 30+mph then your 1st choice is prolly best.

ADD CAPACITORS to any RC controllers you intend to use for driving a bicycle. another tip: keep the wires from the battery to the controller as short as possible. the wires to the motor are not nearly as sensitive. here is a link with a lot of details
http://endless-sphere.com/forums/viewtopic.php?f=28&t=7504&hilit=castle+controllers+add+caps
cogging will not be an issue for a bicycle. I allways recomend to "freewheel" the motor system so you can pedal without spinning the motor.

definatly parralell the batterys when your budget allows. Added capacity will not sag voltage under high loads as mutch & will make all the batteries happeir(& you too :lol: )
good Luck & keep us posted on your coming build.

That 250kv motor is very small. I will decide between my first choice and the one you mentioned before (with 170kv).

Ok, than I'll buy some extra caps for the ESC and keep the wires as short as possible
Yup, I'll have a freewheel between motor and wheel so I can pedal without spinning the motor.

I'll definitely post my upcoming build, I just have to finish some other projects I'm doing right now, in the meantime I'll look around here on the forum.


Thank you for your help Thud, and of course all the other members of Endless-Sphere

 

[sona1111]

Hello, i am also kind of new at this like you, but i thought i would mention i have basically the same goals.

(this is my thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=14309)

Anyway heres what i understand so far about how you can add a motor while keeping pedal power.

1) You can mount it like in the above picture(s) bolted to the spokes, and this is simple and generally easy but theirs a few problems. First of all you will have no gears for the motor, so unless its pretty powerful you may have problems getting up to speed and will have to help by pedaling until the motor gets in a comfortable speed for the size of sprocket you mounted. Second and more importantly, their will be no freewheel, so when you pedal without using the motor you will not only get "drag" but the fact that the motor is "geared up" when pushed in that direction can mean serious alignment problems unless the motor is extremely well mounted (welded).

2) You can mount on the left side with a freewheel. This is slightly more expensive because you not only have to buy the freewheel but also a new hub that is threaded for drive on both sides, which can be slightly expensive. You will still have no motor gears this way, but their wont be any drag problems.

3) You can mount both drives on the right side. Check out this thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=13862 for ideas on how to do that. Advantages of this method are that you can have a freewheel (no drag), and you do not have to buy a new hub to mount the motor. You still wont have motor gears, but it is possible to add them through a new hub that is internally geared. (which is even more expensive) But be warned, pedal to shift gears in internally geared hubs because they are fragile. Disadvantages are that you cannot have rear gears, or a lower amount (3 or less) because they will not fit with the extra freewheel.

4) You can have the motor mounted forward of the pedals. This is interesting. This setup is generally pretty expensive. You will need to buy a freewheel for the motor shaft, and also a freewheel crank. This may not be possible depending on the size of your motor. You basically mount the motor in front of the cranks (pedals) and run a chain from it to one chainring of the freewheel cranks (without freewheel cranks using the motor would spin the pedals, and without the motor freewheel you would get drag when pedaling. The best advantage of this setup is that you can keep your entire rear gear setup the way it is and use them to shift with pedaling and the motor.

If your on a tight budget i would recommend option # 3. (This is the one i have been working on) Otherwise i would say # 4. ALso, i did not mention friction drives because they are basically like option # 1 but even worse.

i hoped this helped somewhat.

 

[Byte]

Hello, i am also kind of new at this like you, but i thought i would mention i have basically the same goals.

(this is my thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=14309)

Anyway heres what i understand so far about how you can add a motor while keeping pedal power.

1) You can mount it like in the above picture(s) bolted to the spokes, and this is simple and generally easy but theirs a few problems. First of all you will have no gears for the motor, so unless its pretty powerful you may have problems getting up to speed and will have to help by pedaling until the motor gets in a comfortable speed for the size of sprocket you mounted. Second and more importantly, their will be no freewheel, so when you pedal without using the motor you will not only get "drag" but the fact that the motor is "geared up" when pushed in that direction can mean serious alignment problems unless the motor is extremely well mounted (welded).

2) You can mount on the left side with a freewheel. This is slightly more expensive because you not only have to buy the freewheel but also a new hub that is threaded for drive on both sides, which can be slightly expensive. You will still have no motor gears this way, but their wont be any drag problems.

3) You can mount both drives on the right side. Check out this thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=13862 for ideas on how to do that. Advantages of this method are that you can have a freewheel (no drag), and you do not have to buy a new hub to mount the motor. You still wont have motor gears, but it is possible to add them through a new hub that is internally geared. (which is even more expensive) But be warned, pedal to shift gears in internally geared hubs because they are fragile. Disadvantages are that you cannot have rear gears, or a lower amount (3 or less) because they will not fit with the extra freewheel.

4) You can have the motor mounted forward of the pedals. This is interesting. This setup is generally pretty expensive. You will need to buy a freewheel for the motor shaft, and also a freewheel crank. This may not be possible depending on the size of your motor. You basically mount the motor in front of the cranks (pedals) and run a chain from it to one chainring of the freewheel cranks (without freewheel cranks using the motor would spin the pedals, and without the motor freewheel you would get drag when pedaling. The best advantage of this setup is that you can keep your entire rear gear setup the way it is and use them to shift with pedaling and the motor.

If your on a tight budget i would recommend option # 3. (This is the one i have been working on) Otherwise i would say # 4. ALso, i did not mention friction drives because they are basically like option # 1 but even worse.

i hoped this helped somewhat.

Hi Sona,

I didn't see you posted in my topic, so I'm a bit late with a reply.
I really like option #3, but I think that isn't possible. Yesterday I had some time left and disassembled the wheel/hub, I found out that I've got a "freehub", it looks like this: http://upload.wikimedia.org/wikipedia/commons/2/2f/Shimanoexagefreehub.jpg. I've been searching on eBay/Google for a freewheel, which isn't threaded, but has the same pattern as my freehub, I couldn't find one... (Sorry, I can't describe this any better, do you know what I'm trying to say?) Could someone tell me if these things actually exist, and do they have a special name?

If option #3 wouldn't work I would also prefer #4 above the other ones, it sounds very good. I haven't disassembled the front of the bike yet, and I want to do that first before I decide for which option # I go for.

About option #1: I don't like it because it's hard to mount the gear on the wheel, and there will be some serious power, I don't think that will held up too long.
About option #2: Too expensive indeed. A new hub is very expensive and my Dad told me it's hard to mount the spokes to the hub, could someone confirm this?
About option #friction drive: Forget it

Your post is very useful, many many thanks for that!


Now I have to know if there are some freewheels WITHOUT thread but WITH splines. As said, if this thing exists I'll go for option #3, if this thing doesn't exist I think I'll go for #4.

EDIT: I just found this topic: http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=13532 I'll read through that one, there should be some good information I think

 

[Solcar]

Hi Byte

I am considering option 2 on a future project with a notable qualification. I would epoxy the freewheeling sprocket onto the nonthreaded bearing housing on the left side of the rear hub. I estimate it can be strong enough for my few hundred watts maximum power. Yet if your set-up uses high power it would seem less feasible.