hi, every body. but a big OOPS! as i have just realised that this site is for electric bikes, and i want petrol engines. however there are some smart guys here. and i got carried away with jdcburg idea on dual free wheel sprockets from the crank. i thought he had come up with what i was looking for. then realised, after several readings, it was only for electric drives not a problem in itself. i thought it would still work, but the drive is still coming off the right side of the crank. nice work jdc. but i want a southpaw freewheel sprocket to come off the left side of the crank, as my 4 stroke engines drive cog is also on the left, i am hoping to go vertical with a short chain to the crank southpaw cog. this will eliminate having to go to the left side of the rear wheel. So what i need is a southpaw crank spindle, if such a thing exists, as far as i know it has never been done. even sickbike parts can,t help. he said that he has tried everything, but got no answer, i know where to get the southpaw freewheel sprocket in the uk. but even they have not answered my e mail enquiry. so jcb you got close to what i was thinking but on the wrong side. thousands of bikers around the world a wating for this breakthrough, without having to use a jackshaft to transfer drive from the left to the right, and still use all the bikes gears for peddeling and motoring. thanks for your time. klondyke
Dual Freewheel Front Sprocket system
- Thread starter jdcburg
- Start date
ztripoli
1 µW
- Joined
- Nov 17, 2010
- Messages
- 2
Hey guys,
I'm working on a project for my engineering class where we are trying to develop a dual freewheel system for an electric bike. Bear with me, because I'm new to a lot of this bike terminology and stuff, but right now I'm having trouble figuring out exactly what attaches to what and how. I see that those freewheel adaptors have 4 or five holes that get bolted to to the sprocket directly, but where do the threads in the center of the adapter screw onto? Is the right crank arm typically threaded somehow? And again for the motor sprocket, once I bolt that sprocket onto the freewheel adaptor then what am I threading that piece onto?
Sorry these questions are tough without pictures and diagrams.
-Zach
I'm working on a project for my engineering class where we are trying to develop a dual freewheel system for an electric bike. Bear with me, because I'm new to a lot of this bike terminology and stuff, but right now I'm having trouble figuring out exactly what attaches to what and how. I see that those freewheel adaptors have 4 or five holes that get bolted to to the sprocket directly, but where do the threads in the center of the adapter screw onto? Is the right crank arm typically threaded somehow? And again for the motor sprocket, once I bolt that sprocket onto the freewheel adaptor then what am I threading that piece onto?
Sorry these questions are tough without pictures and diagrams.
-Zach
Andje
10 kW
- Joined
- Aug 25, 2010
- Messages
- 779
http://www.sickbikeparts.com/Manuals/SBP2%20Manual001%20Rev%20A.pdf
check out page three; this is an installation manual for their gas engine conversion kit, but the concept of how the chain wheel and axle are modified is there. Basically, your pedals are still attached to the axle, and the chain ring is on a freewheel on the axle, rather then being directly attached, meaning that it can spin forward independantly of the axle. This means that as you pedal forward you put power the the chain, but if you want you can stand on the pedals all day and just let the engine turn it.
i must admit to having been confused so far at the dual chain conversions i have seen on here. Between running two chains mm apart on the right or even just the hassle of installing an extra sprocket on the left hand side or just running all my power through the chain ring, i think this style of independent free wheel makes much more sense. A lot of people have problems with the low quality freewheel bearing supplied with these kits and upgrade to the Eno freewheel, i know i personally have at least 750km hard riding on a gas bike kit using the stock one with no problems (almost everything else on that thing has broken at some point lol).
ztripoli
1 µW
- Joined
- Nov 17, 2010
- Messages
- 2
Thanks for the reply Andje. I understand the basic functionality and how the freewheel system works, my question is more about the visualizing the specific connection points. For example, in the picture from briangv99, I see three sets of threads on his bottom bracket: one on the left side of the spindle, one one the right side of the spindle, and one on the right crank arm. Which of these three sets of threads am I screwing my freewheel adapter onto?
-Zach
Andje
10 kW
- Joined
- Aug 25, 2010
- Messages
- 779
the silver spindle screws through the bottom bracket on your frame; both of those sets of threads will be inside the bike. The threads on your crank will normally attach to one of the freewheels, and then any chain rings or other freewheels will attach to that. However, here he is using a modified freewheel adapter to connect the first eno to the spindle, and not to the pedals if i understand it.
So he ground off the threads on the crank on the right hand side. Then left to right he has his first freewheel that goes to the back wheel, his freewheel adapter that bolts to the first eno and then allows the second eno to be threaded to that, and that eno has an adapter in it that allows the pedals to turn the center of that freewheel, thus turning the first freewheel as well. I think
So he ground off the threads on the crank on the right hand side. Then left to right he has his first freewheel that goes to the back wheel, his freewheel adapter that bolts to the first eno and then allows the second eno to be threaded to that, and that eno has an adapter in it that allows the pedals to turn the center of that freewheel, thus turning the first freewheel as well. I think
briangv99
1 kW
Cheers Andje, you described exactly what my dual freewheel does perfectly. I can understand though if it is a bit tricky to visualise how it all fits together and works.
It is similar to this kit from sick bikes except with an extra freewheel.
http://www.sickbikeparts.com/Manuals/SBP 4T Manual001 Rev A.pdf
It is similar to this kit from sick bikes except with an extra freewheel.
http://www.sickbikeparts.com/Manuals/SBP 4T Manual001 Rev A.pdf
briangv99 said:Nice design jdc
Left to right, SBP White Eno with spacer ring, freewheel adaptor, GGoodrum 3-speed freewheel adaptor, SBP White Eno, Eclipse 153mm BB (reversed), Onza T-Pro pedal minus the threaded collar and slightly thinned.
Here it is assembled, with a SBP 36t sprocket with the spacer ring in the middle -
On the bike with a Extron kevlar 92T #219 sprocket and adapter -
The pedal drives the BB which in turn connects to the first freewheel adaptor. The reason for going this way was so the freewheel closest to the frame takes the pedalling sprocket and I can achieve a straight chain line.
The second reason for this setup is so the chain is not backdriven, and I can achieve a 10:92 reduction in one step without the problems Deec had back driving a small primary gear and freewheel.
Brian
Brian,
How did it work out for you with the big HXT motor? What controller did you use?
briangv99
1 kW
I put that project on the back-burner whilst I was working on another ebike, so unfortunately haven't tested it. I've now got it fitted to my KeeWee Cromozone DH and changed the BB spindle over to the 206mm Sickbikes BB that has a keyway machined in. Not that the MS FW adapter broke, I just think a keyway will be stronger than 2 set screws for transmitting pedalling torque.
boostjuice
10 kW
h0tr0d said:
ES member 'recumpence' (Matt Shumaker)
boostjuice
10 kW
Idontwanttopedal
1 kW
Any one selling this as a kit
RWP
1 kW
I would like to better understand the second part from the left - the 'freewheel adapter'. What is this part?briangv99 said:...here's my take (as yet untested) at the design. Here are the bits all lined up -
Left to right, SBP White Eno with spacer ring, freewheel adaptor, GGoodrum 3-speed freewheel adaptor, SBP White Eno, Eclipse 153mm BB (reversed), Onza T-Pro pedal minus the threaded collar and slightly thinned.
Looks like it has a thread for a freewheel and, I can't see this, a needle roller bearing that rides on the BB shaft...is this correct?
Looks like the inner freewheel and spacer mount on the 'GGoodrum adaptor' - where does the 'freewheel adapter' fit in?
I get it's the support for the inner freewheel but I am not clear how it all goes together.
Where can one get this 'freewheel adapter' part?
Thanks - it's beautiful.
Roy
briangv99
1 kW
Also see BoostJuice's version of what I did, except I think he did a better job off it
http://endless-sphere.com/forums/viewtopic.php?f=28&t=41547&p=612342#p612342
PS - some of the parts feature in the Sick Bike Parts shift kit (the 206mm BB and keyway FW adaptor)
http://endless-sphere.com/forums/viewtopic.php?f=28&t=41547&p=612342#p612342
PS - some of the parts feature in the Sick Bike Parts shift kit (the 206mm BB and keyway FW adaptor)
