E.S. bottom bracket drive.
- Thread starter Miles
- Start date
fabiograssi
100 W
I'm not technical, so some "normal people" requeriments:
- silent operation
- smooth acceleration (good to the city traffic, to the frame and to the cassete)
- solve the "torsion" issues im motor/reduction aggregate
- the bb plate must be "shaved" or "thin" enough to respect the rear susp movement (stays, I don't know the correct name in english for the back susp set)
- at least 44 teeths on crank, if possible (here, maybe some frame issues...)
- silent operation
- smooth acceleration (good to the city traffic, to the frame and to the cassete)
- solve the "torsion" issues im motor/reduction aggregate
- the bb plate must be "shaved" or "thin" enough to respect the rear susp movement (stays, I don't know the correct name in english for the back susp set)
- at least 44 teeths on crank, if possible (here, maybe some frame issues...)
To give an approximate idea of the capabilities of belt drives:
5M HTD 15m width 14t to 80t ......... 3Nm (GNG kit sans idler)
5M HTD 15mm width 18t to 80t ........ 7.5Nm
8M HTD 15mm width 15t to 60t ........ 11.5Nm
Minimum centre distances used for all the above.
5M HTD 15m width 14t to 80t ......... 3Nm (GNG kit sans idler)
5M HTD 15mm width 18t to 80t ........ 7.5Nm
8M HTD 15mm width 15t to 60t ........ 11.5Nm
Minimum centre distances used for all the above.
bzhwindtalker
100 kW
The issue with #219 and 8mm chain is that the sprocket will be biger than the 80t pulley if we want the same ratio in the first stage. With #25, matching the original drive compactness seems possible, but it may not last until duplex chain is used.
bzhwindtalker
100 kW
I have no idea about the impact on pedability (gotcha, one new word..) of having the freewheel on the left side of the axle. This is one key features of the original drive that we should not loose. The drive should pedal like a normal bike and feel like it. But doing this would allow to use a 10t fixed sprcket or go with #35 or #219 and get all the reducion we need there.
Thud
1 MW
I have this all designed & in the manufacturing stage.
this includes a refined bearing support for the freewheeling crank, an enclosed, maintance free 6-1 reduction box, a 5mm primary reduction.
look for it soon on GCinDC's new DHcomp thread I have been putting off starting.
here is a teaser of a compound sprocket in the 6-1 reduction box (that is 58mm wide bu 107mm long)
this includes a refined bearing support for the freewheeling crank, an enclosed, maintance free 6-1 reduction box, a 5mm primary reduction.
look for it soon on GCinDC's new DHcomp thread I have been putting off starting.
here is a teaser of a compound sprocket in the 6-1 reduction box (that is 58mm wide bu 107mm long)
bzhwindtalker
100 kW
I am more thinking about the added inertia when under pedal power only. The drag should not be too bad with good bearings.
Thud, will you use a "rc" motor?
Thud, will you use a "rc" motor?
A cheaper ecospeed using the small MAC motors would be a killer app, IMHO. I've thought about doing such a thing but you guys are so much more talented with these mechanical bits than i.
Consider me glued to this thread.
Consider me glued to this thread.
Thud
1 MW
If anyone has followed any of my posts, they will recall the BB drive I built with a buddy for his everyday bike.
After testing that set up & playing with the gearing, it is my 1st choice for a true "bicycle" motorazation. (spell that
)
It isn't crazy fast like the moped class conversions I am associated with, but the synergy of having an extra horspower or two blended into your normal cadance is really a great feeling on a bicycle & frankly the only way to fly & still be a bicycle IMHO.
I drew the thing up over a year ago & have been putting off building it for fear of looking like a plageriser for (i forget the guy now who came up with the system we see now on the gng unit....I recall him better for havin a phase current sensor on his controller) Now that the GNG kits are here & the masses are seeing what it feels like....I really belive these are going to dominate for any one who is into off roading & needing some serious hill climbing potential.
you see the GNG thread where the guys are overvolting & looking for more (moar!) power/speed & everything else...but the important issue is matching the human's pace to keep the thing enjoyable.
Biz, (yes, the ill named "rc" motors)I am leaning heavily toward the 80/85 out runners...they fit between cranks very nicely & will deliver 3kw with out too much fuss. (& I have a bunch of them in hand already hehe) these are much quieter in application once re-wound & terminated & running on a Xiechang controller than any true RC set up with a Castle controller.
Not silent as a DD hub motor.....but nothing ever will be.
I'll be starting a build thread with all the mojo & pictures of Gregs Giant DH Comp I have sitting in my basment. This bike will require a custom crank spindle to fit the freewheel & sprockets onto & that will be a key to the bikes ultimate success.
more later.
After testing that set up & playing with the gearing, it is my 1st choice for a true "bicycle" motorazation. (spell that
)It isn't crazy fast like the moped class conversions I am associated with, but the synergy of having an extra horspower or two blended into your normal cadance is really a great feeling on a bicycle & frankly the only way to fly & still be a bicycle IMHO.
I drew the thing up over a year ago & have been putting off building it for fear of looking like a plageriser for (i forget the guy now who came up with the system we see now on the gng unit....I recall him better for havin a phase current sensor on his controller) Now that the GNG kits are here & the masses are seeing what it feels like....I really belive these are going to dominate for any one who is into off roading & needing some serious hill climbing potential.
you see the GNG thread where the guys are overvolting & looking for more (moar!) power/speed & everything else...but the important issue is matching the human's pace to keep the thing enjoyable.
Biz, (yes, the ill named "rc" motors)I am leaning heavily toward the 80/85 out runners...they fit between cranks very nicely & will deliver 3kw with out too much fuss. (& I have a bunch of them in hand already hehe) these are much quieter in application once re-wound & terminated & running on a Xiechang controller than any true RC set up with a Castle controller.
Not silent as a DD hub motor.....but nothing ever will be.
I'll be starting a build thread with all the mojo & pictures of Gregs Giant DH Comp I have sitting in my basment. This bike will require a custom crank spindle to fit the freewheel & sprockets onto & that will be a key to the bikes ultimate success.
more later.
ElliottE
100 mW
Fabio, here's the names of the main components used to construct a basic bicycle frame, from front to back:fabiograssi said:
Head Tube (The tube that holds the front fork assembly.)
Top Tube (The tube on top, between the head tube and the seat tube.)
Down Tube (The tube below the Top Tube, between the head tube and the bottom bracket.)
Seat Tube (The tube that the seat post goes into)
Bottom Bracket (The very short, threaded tube that goes crossways in the frame, that the pedal crankset is mounted in.)
Chain Stays (The two tubes between the Bottom Bracket and the Dropouts.)
Seat Stays (The two tubes between the top of the Seat Tube and the Dropouts.)
Dropouts (These are the parts that hold the rear wheel assembly.)
I hope this is helpful to you.
E.
Thud
1 MW
I doubt the mac motors are "higher quality" than the 80mm outrunners. The Halls are a bonus, the big outrunners (even the high dollar Astros that have burned up) get a bad rap from the threads where they are pushed so far past their limits they never had a chance.
set up with a proper controller & reasonable peak wattage input, they will be reliable as a hammer.
But I am not be opposed to looking at the larger Mac motors again....so far, all the photo's Ive seen of them have left me un-impressed.
spinningmagnets
100 TW
If one of the goals of this prototyping is a BB-drive similar to the GNG that has a more rigid bracket (less flex under load), it might be useful to discuss at this stage whether its better to have a one-piece bracket that has to be fitted to the various widths of bottom-brackets (like stock), or a more adjustable multi-piece bracket (like the AFT bracket). http://endless-sphere.com/forums/viewtopic.php?f=28&t=44572
Christerljung used a big-hit frame, and since it had a 72mm wide BB, he had to file off 4mm to make the 68mm GNG braket fit. Nobody else has mentioned needing to do this, but I suspect there are quite a few frames that may have a 72mm wide BB.
I feel a one-piece bracket has the potential to be stiffer and more trouble-free, but it might be better to have it fit a 72mm wide BB, and have builders space it with an additional thin locking ring, as opposed to a small percent of builders needing to file/grind their BB narrower?
I only bring this up because the stock GNG bracket seems acceptable for 1000W, and the desire an ES engineered BB-drive sounds as though its driven by interest in a 3000W BB-drive with perhaps a slightly larger and lower-kV motor...
crossbreak is experimenting with de-shelling a geared hub, resulting in a large and inexpensive outrunner of the size and shape that I feel is very appropriate for a BB-drive. cell_man has these (larger than the one crossbreak is playing with) in 5 different kVs. http://endless-sphere.com/forums/viewtopic.php?f=28&t=45245&p=659522#p659522
Christerljung used a big-hit frame, and since it had a 72mm wide BB, he had to file off 4mm to make the 68mm GNG braket fit. Nobody else has mentioned needing to do this, but I suspect there are quite a few frames that may have a 72mm wide BB.
I feel a one-piece bracket has the potential to be stiffer and more trouble-free, but it might be better to have it fit a 72mm wide BB, and have builders space it with an additional thin locking ring, as opposed to a small percent of builders needing to file/grind their BB narrower?
I only bring this up because the stock GNG bracket seems acceptable for 1000W, and the desire an ES engineered BB-drive sounds as though its driven by interest in a 3000W BB-drive with perhaps a slightly larger and lower-kV motor...
crossbreak is experimenting with de-shelling a geared hub, resulting in a large and inexpensive outrunner of the size and shape that I feel is very appropriate for a BB-drive. cell_man has these (larger than the one crossbreak is playing with) in 5 different kVs. http://endless-sphere.com/forums/viewtopic.php?f=28&t=45245&p=659522#p659522
ohzee
100 kW
Hope no one minds my question , but are you going to start offering this product Miles or is this just a discussion on what your working on ?
Thud
1 MW
Just a side note also regarding BB drive set up with a free-wheeling crank.
IMHO the weak link is the unsupported freewheel on the cranks themselves. I have used the standard dicta's that come with the SBP set ups & also the big money White industries freewheel....the dicta runs better in freewheel mode than the WI unit.....but the chepo only has 2 small pawels for pedaling & is much weaker under pedal.
I think a proper crank shaft with a fitted bearing to handle the loads will be the thing to build on.......much easyer on a cartrige style BB than a standard with regards to machining bearing races & the hardening required for the angular contact balls.
I can't answer for Miles....but I have this one in my catolog now. :wink:
IMHO the weak link is the unsupported freewheel on the cranks themselves. I have used the standard dicta's that come with the SBP set ups & also the big money White industries freewheel....the dicta runs better in freewheel mode than the WI unit.....but the chepo only has 2 small pawels for pedaling & is much weaker under pedal.
I think a proper crank shaft with a fitted bearing to handle the loads will be the thing to build on.......much easyer on a cartrige style BB than a standard with regards to machining bearing races & the hardening required for the angular contact balls.
I can't answer for Miles....but I have this one in my catolog now. :wink:
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