Miles, Is there room on a freehub for one broached ENO (for the motor)...and then one of the cheaper de-threaded freewheel/fixed-gear-adapter combo's (for the pedals)?
Fitting freewheels to splined freehub drivers
- Thread starter Miles
- Start date
Hi Spinning,
I've just tried it.... There's really not enough engagement between the splines of the cog and those on the driver... The cog has to go on the outside of the freewheel which means most of it is hanging off the end.
You might be able to modify or make a screw in end-cap, with 'ears' that fit in the recessed pockets of the freewheel.
I've just tried it.... There's really not enough engagement between the splines of the cog and those on the driver... The cog has to go on the outside of the freewheel which means most of it is hanging off the end.
You might be able to modify or make a screw in end-cap, with 'ears' that fit in the recessed pockets of the freewheel.
I have read the first 11 pages here, and I realized something.
You only need the freewheeling cog for the pedal drive chain, not the motor driven one. This is because you should be able to easily bolt your large chainring onto the back of a 7 speed cassette (which is obviously already splined). You don't need the motor sprocket to freewheel unless you really need to pedal the bike without motor drag. Use a few spacers to move the 34 ring further away from the spokes. If you really want to use the WI freehwheel on the motor, the SBP one is designed to have their chainrings mounted, so you could mount your big chainring on there 44 or whatever.
The remaining issue is getting your cheap freewheeling sprocket on the splined hub. But to me, it should be less of an issue since it won't require as much of a quality interface as the motor one would need - just enough for whatever small amount of pedaling you will do.
OR, you could solve this whole problem by using freewheel cranks, which are only like $50 with chainrings at sickbikeparts.
-Motor drive freewheels with splined cassette.
-Pedal chain spins with motor, but freewheel cranks allow you to coast.
-Pedaling with motor off will have some drag, but who really pedals a high powered ebike with the motor off? I do a little on my current low powered rig, but that's at 8mph in parking lots. It's a non-issue IMO.
- Only real sacrifice is that it won't be as quiet, with the pedal chain spinning. But if it's clean and lubed, it shouldn't be too noisey. At high speeds, wind noise drowns out any chain noise. I know when I'm sprinting 55mph down a hill on my road bike, with my chain at 170rpms, I never notice the noise. Even when I do granny gear sprints at 200rpms at 30mph, the noise isn't too bad. (The bulk of that noise is the chain running through those derailier pulleys. If you have a singlespeed pedal chain, a proper chain tensioner should be quieter.)
What do you guys think?
I want to get all the info out of this thread but it's 30 more pages to read! Can anyone give me an update on this project?
I would be in for a splined freewheeling sprocket if it is available now.
You only need the freewheeling cog for the pedal drive chain, not the motor driven one. This is because you should be able to easily bolt your large chainring onto the back of a 7 speed cassette (which is obviously already splined). You don't need the motor sprocket to freewheel unless you really need to pedal the bike without motor drag. Use a few spacers to move the 34 ring further away from the spokes. If you really want to use the WI freehwheel on the motor, the SBP one is designed to have their chainrings mounted, so you could mount your big chainring on there 44 or whatever.
The remaining issue is getting your cheap freewheeling sprocket on the splined hub. But to me, it should be less of an issue since it won't require as much of a quality interface as the motor one would need - just enough for whatever small amount of pedaling you will do.
OR, you could solve this whole problem by using freewheel cranks, which are only like $50 with chainrings at sickbikeparts.
-Motor drive freewheels with splined cassette.
-Pedal chain spins with motor, but freewheel cranks allow you to coast.
-Pedaling with motor off will have some drag, but who really pedals a high powered ebike with the motor off? I do a little on my current low powered rig, but that's at 8mph in parking lots. It's a non-issue IMO.
- Only real sacrifice is that it won't be as quiet, with the pedal chain spinning. But if it's clean and lubed, it shouldn't be too noisey. At high speeds, wind noise drowns out any chain noise. I know when I'm sprinting 55mph down a hill on my road bike, with my chain at 170rpms, I never notice the noise. Even when I do granny gear sprints at 200rpms at 30mph, the noise isn't too bad. (The bulk of that noise is the chain running through those derailier pulleys. If you have a singlespeed pedal chain, a proper chain tensioner should be quieter.)
What do you guys think?
I want to get all the info out of this thread but it's 30 more pages to read! Can anyone give me an update on this project?
I would be in for a splined freewheeling sprocket if it is available now.
I'm trying to find this Sram Dual Drive. Seems kind of rare.
Big question: how is the efficiency of the dual drive, and how will they handle high powered loads?
I just read something about them not being designed for tandem use (high power).
I read that the other internal gear hubs are at about 92% efficiency, which is not that great IMO.
Big question: how is the efficiency of the dual drive, and how will they handle high powered loads?
I just read something about them not being designed for tandem use (high power).
I read that the other internal gear hubs are at about 92% efficiency, which is not that great IMO.
liveforphysics
100 TW
veloman said:
Pedaling with no motor drag is exactly what we like.
No compromises drivetrain. veloman said:
Do you have any ideas for making getting a cheap freewheel onto the splined hub??? We compiled some of the best minds on this forum together for weeks trying to solve that very problem. If you've got a clever alternative, please share it with us!!!
veloman said:
Then you're back with your bicycle chain and front chain-rings spinning at 50mph speeds... Not only makes a terrible racket, but tends to impressively ball-up into a mess when you go over a bump wrong. lol But, it IS an option, and if you're willing to make that compromise, it's certianly an option. The cyclone kits use the racheting front chainwheel setup, and it does work.
veloman said:
Paypal Thud $20. Send me freewheels. I've been broaching them for anyone and even paying return shipping to send them back at my own expense.
I'm actaully getting my father to take over the broaching work though, because he works at the shop where we have the broaching setup, and I tend to work 6 days a week or so and don't often want to spend my day off broaching. lol He doesn't like the idea of working for free as much as I do... lol
The member SloBuild made a fantastic donation after sending me 8 freewheels to broach, and it's going to cover the cost of the new broach (this one is rapidly loosing the corners of the teeth now... ), plus give some motivation to my dad to broach for me, because after I buy a new broach, I'm giving the residual to him.
Also... as dad's so often do... he made some subtle revisions to the process that improved it quite a lot. We've gone to press-fit's on them now, very snug, and this has reduced the potential for wobble on a large diameter sprocket.
I actually made a real-time video in HD showing every step of the broaching process, and the tools used to make it work. It's not an exciting video, but it's pretty educational.
-Luke
Thanks for the reply.
I can live with motor drag when pedaling. But you make a good point about the chainrings spinning at 50mph. I love engineering challenges, so i will continue to brainstorm ways to achieve that result.
I will consider sending you the cheapie freewheel I have (for the pedal chain drive!)and Thud $20. I'll prob go my route on the motor drive since I don't care too much about motor drag, and it will save me from buying an WI ENO.
I've read a lot of your work on this site, great stuff. I'm so glad I found such a resource. To me it feels like "endless-resource.com" because I could spend months endlessly reading and learning here. Props to all for that.
I just saw your Costa Rica vid too, pretty cool. I'm a young guy myself, (spandex roadie looking for a fast bike commuter/toy), love engineering stuff, just don't have any good resources here.
I'm currently looking for a suitable full-suspension bike for this next project of mine. Still unsure about where I'll be mounting. Looking at this motor,
http://hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=7870&Product_Name=TGY_AerodriveXp_SK_Series_63-74_170Kv_/_3250W
Next step is to figure out how to support the shaft with a bearing so the motor bearings don't fail under torque.
-Rich
I can live with motor drag when pedaling. But you make a good point about the chainrings spinning at 50mph. I love engineering challenges, so i will continue to brainstorm ways to achieve that result.
I will consider sending you the cheapie freewheel I have (for the pedal chain drive!)and Thud $20. I'll prob go my route on the motor drive since I don't care too much about motor drag, and it will save me from buying an WI ENO.
I've read a lot of your work on this site, great stuff. I'm so glad I found such a resource. To me it feels like "endless-resource.com" because I could spend months endlessly reading and learning here. Props to all for that.
I just saw your Costa Rica vid too, pretty cool. I'm a young guy myself, (spandex roadie looking for a fast bike commuter/toy), love engineering stuff, just don't have any good resources here.
I'm currently looking for a suitable full-suspension bike for this next project of mine. Still unsure about where I'll be mounting. Looking at this motor,
http://hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=7870&Product_Name=TGY_AerodriveXp_SK_Series_63-74_170Kv_/_3250W
Next step is to figure out how to support the shaft with a bearing so the motor bearings don't fail under torque.
-Rich
liveforphysics
100 TW
I would love to broach cheapy freewheels, but they use hardened inner races, which can't be broached.
The ENO uses a seperate internal sealed radial bearing, so it can use non-hardened stainless steel for it's inner race, which is just soft enough to be broached. The cheapy freewheels are made of a metal about as hard as the teeth on the broach...
The ENO uses a seperate internal sealed radial bearing, so it can use non-hardened stainless steel for it's inner race, which is just soft enough to be broached. The cheapy freewheels are made of a metal about as hard as the teeth on the broach...
Oh, that is a bummer, however!
I think I just solved it. You need to use the WI freewheel, or one with protruding ridges on one side.
See the pic below.
Using a 12 cog from a 9 speed cassette:
First grind down those protruding ridges on the WI freewheel, so they match the teeth on the 12 cog. Then they will mate together and lock once the whole hub assembly is filled with spacers and locked with the lockring. The freewheel will be locked in place with the 12 cog.
Wait, I'm not sure those ridges go far enough towards the outer diameter. I don't have a WI freewheel....
There still has to be some way to connect this 12 cog to a freewheel without destroying the freewheel by welding it.
Edit: I know, just use a larger cog, should have more metal to keep itself intact, while matching up to those ridges. Grind down the splined cog appropriately!
I think I just solved it. You need to use the WI freewheel, or one with protruding ridges on one side.
See the pic below.
Using a 12 cog from a 9 speed cassette:
First grind down those protruding ridges on the WI freewheel, so they match the teeth on the 12 cog. Then they will mate together and lock once the whole hub assembly is filled with spacers and locked with the lockring. The freewheel will be locked in place with the 12 cog.
Wait, I'm not sure those ridges go far enough towards the outer diameter. I don't have a WI freewheel....
There still has to be some way to connect this 12 cog to a freewheel without destroying the freewheel by welding it.
Edit: I know, just use a larger cog, should have more metal to keep itself intact, while matching up to those ridges. Grind down the splined cog appropriately!
Attachments
It's worth reading the whole thread, veloman :wink:
http://www.endless-sphere.com/forums/viewtopic.php?p=255091#p255091
This wouldn't work with the ENO - in order to get it to fit over the major diameter of the splines, you would need to machine away the material that you need to lock onto...
http://www.endless-sphere.com/forums/viewtopic.php?p=255091#p255091
This wouldn't work with the ENO - in order to get it to fit over the major diameter of the splines, you would need to machine away the material that you need to lock onto...
flyinmonkie
10 kW
If you want to use one splined eno and one cheap freewheel, you could swap your freehub body with a uniglide freehub body. This is threaded on the end as the last few sprockets used to thread on, instead of a collar threaded internally. The splined eno could go on the inside and the cheap freewheel could thread on the outside. Some said the fixed gear adapter wouldn't work on a sram dd, so this probably wouldn't either, but below is how it works on a standard hub.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=8492&start=15
Clay
http://endless-sphere.com/forums/viewtopic.php?f=28&t=8492&start=15
Clay
Does anyone know the efficiency of the Dual Drive? I might consider it, still deciding.
If I stick with a normal hub, that uniglide freehub seems like it would be perfect for me.
Eliminating the use of freewheel cranks would cut 2 lbs off the bike, less cost, and of course keep things quieter/safer at speed.
If I stick with a normal hub, that uniglide freehub seems like it would be perfect for me.
Eliminating the use of freewheel cranks would cut 2 lbs off the bike, less cost, and of course keep things quieter/safer at speed.
liveforphysics
100 TW
veloman said:
The efficiency is tough to quantify. It's going to depend on the gear.
I took a set of explicit photos of the inside of the SRAM DD. In 2nd gear for example, it's locked like a solid hub and spinning only on the wheel bearings, meaning it should have no efficiency loss over a normal hub. In 1st and 3rd, it runs through some planetary gear sets, which will of course eat a few percent each.
liveforphysics
100 TW
I made a thread with some explict video of the entire process for those folks who are interested to see how the freewheel broaching works, or for folks who would like the service performed to arange things.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=17602
-Luke
http://endless-sphere.com/forums/viewtopic.php?f=28&t=17602
-Luke
RWP
1 kW
12p3phPMDC
1 kW
- Joined
- Mar 16, 2009
- Messages
- 462
Nice, another dual drive!
That's a massive sprocket, Aluminum? Where did you get it?
Did you get your dual drive hub on ebay? It seems like that's the best bet these days.
What's the motor setup look like?
Way to go, I am quite envious. And the button head cap screws look SO slick.
Katou
Did you get your dual drive hub on ebay? It seems like that's the best bet these days.
What's the motor setup look like?
Way to go, I am quite envious. And the button head cap screws look SO slick.
Katou
RWP
1 kW
OK Ok - Check it out:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=17738
http://endless-sphere.com/forums/viewtopic.php?f=28&t=17738
Miles, my apologies for hacking up the nice graphic you drew. I like the several oddly shaped keys you show here. I'm sure thud or any one of the other garage machinists here could cut a long key-bar with the cross-sections shown. Then (of course) chop off some short pieces of the needed length. However, I can't do that myself, and I have been pondering what I am capable of right now with my limited resources.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=14818&start=135#p437909
Since these freewheel in one direction, we only need a solid connection in one direction. I'm thinking it may be possible to use square-ish profile keys (thinned to fit with a file and measuring calipers), and 4 or so of them placed so that they only have a solid metal-to-metal contact in the driving direction.
The rear side of the key has space that might be filled with some type of metal-epoxy (JB-Weld/Devcon?) with a waxy substance on the freehub during the drying process, so that the adaptation only sticks to the ID of the FW?
I liked your idea of the "dogged-cog" as a side-connector for a FW, but you mentioned that there wasn't enough length on the freehub driver for two paired sets. Perhaps use one Dogged-cog/FW for the motor, and a second FW for the pedals (less torque?) which uses the above-described four-square-keys/epoxy?
I don't know if the Dicta inners are thick enough for four shallow file-cut key-slots, but if its a yes, its something I could cheaply and easily do (thanks to two of your creative ideas). As a plus, the motor-FW is the most likely to break or wear out, and in this scenario the motor-FW is the least modified (ID threads merely shaved/filed shallower).
This arrangement allows a very small solid cog (11T?) on the motor shaft, and no freewheeling BB is needed. The dual splined ENOs on a SRAM-DD is an elegant solution, but its priced above my current budget.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=13532&start=585#p255091
http://endless-sphere.com/forums/viewtopic.php?f=28&t=14818&start=135#p437909
Since these freewheel in one direction, we only need a solid connection in one direction. I'm thinking it may be possible to use square-ish profile keys (thinned to fit with a file and measuring calipers), and 4 or so of them placed so that they only have a solid metal-to-metal contact in the driving direction.
The rear side of the key has space that might be filled with some type of metal-epoxy (JB-Weld/Devcon?) with a waxy substance on the freehub during the drying process, so that the adaptation only sticks to the ID of the FW?
I liked your idea of the "dogged-cog" as a side-connector for a FW, but you mentioned that there wasn't enough length on the freehub driver for two paired sets. Perhaps use one Dogged-cog/FW for the motor, and a second FW for the pedals (less torque?) which uses the above-described four-square-keys/epoxy?
I don't know if the Dicta inners are thick enough for four shallow file-cut key-slots, but if its a yes, its something I could cheaply and easily do (thanks to two of your creative ideas). As a plus, the motor-FW is the most likely to break or wear out, and in this scenario the motor-FW is the least modified (ID threads merely shaved/filed shallower).
This arrangement allows a very small solid cog (11T?) on the motor shaft, and no freewheeling BB is needed. The dual splined ENOs on a SRAM-DD is an elegant solution, but its priced above my current budget.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=13532&start=585#p255091
Spinning,
I'm not sure how hard the Dicta inners are? I don't have one to test. It might not be easy to add additional slots... In any case, even shallow ones couldn't continue much past the depth of the existing slots.
The 9-spd cassette driver is exactly the same width as 2 freewheels - no more, unfortunately...
I'm not sure how hard the Dicta inners are? I don't have one to test. It might not be easy to add additional slots... In any case, even shallow ones couldn't continue much past the depth of the existing slots.
The 9-spd cassette driver is exactly the same width as 2 freewheels - no more, unfortunately...
Lenk42602
10 kW
Aargh.
Any of the founding fathers of this thread have a splined freehub broached freewheel laying around in their tool boxes before I start hand filing one?
len
Any of the founding fathers of this thread have a splined freehub broached freewheel laying around in their tool boxes before I start hand filing one?
len
John Bozi
100 kW
Hi all, I am a bit off topic, but this thread seemed closest in knowledge base to what I am looking for, and I have googled this for days and can't find the dimensions I am after. Basically I want to make my own freehub sprockets / adapters etc. to the common splined freehub. My measurements are always terrible, I am guessing roughly
does the file look right?
If anyone has a DXF file would be seriously make my day!
This is the start
EDITI spent ages trying different things according to the logic of metric and I am guessing this is right.
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