New Bafang Crank-Drives
- Thread starter d8veh
- Start date
sculptingman
100 mW
- Joined
- Apr 21, 2014
- Messages
- 38
Bafang comes with a dish offset steel chainring that is 48t.ebike11 said:
Lectric-cycles sells milled aluminum adapters for mounting 4 point and 5 point chainrings... But they will shift your chainline outward from 50mm to 54 or more... So for some rear derailuer rigs that might be problematic for your low gears.
You might need a chainguide.
Somebodystopme!!
10 W
- Joined
- Dec 24, 2013
- Messages
- 72
sculptingman said:
Are there any good aftermarket chain guides to recommend for the BBS02? I have an issue with the original chainring de Railing while in low gears.
samsavvas
100 W
tomjasz said:
Just being a bit number-obsessive, I think you mean 68mm...
All traditional-style Pashleys will have a 68mm BB.
Savvas
samsavvas
100 W
ebike11 said:
Look up eride in previous posts or in the 'for sale - new' section. He has a rebated 130mm bcd adapter which apparently minimises chainline shift. He also does an adapter for a compact mtb crank.
Incidentally, I run an 8 speed 11-28 cassette with a 60T plain (no ramps) chainring on a suspended bike and have no chain loss problems. My chainring is more or less in-line with top gear (smallest sprocket).
Savvas
tomjasz
1 GW
'merkins, in over 62 years I've never had a class in metrics. Much less proper usage. All new. Thanks, but it adds what to the conversation? Certainly no one was confused.:wink:samsavvas said:
samsavvas
100 W
Somebodystopme!! said:
AFAIK the only problem you are likely to encounter with regard to rear the derailleur it the fact that it may (depending on how you set your bike up) have to deal with a greater or less degree of chain-wrap. Inadequate chain wrap could cause your chain to fling about wildly I suppose but it's not a problem I encounter. With a 60T chainring (changed from 56T) - to ensure proper RD functioning and wrap - I had to add several links. As most MTB chains will be quite long enough to start with, this was no problem. If you haven't adjusted your rear der. for chain wrap before, just follow Saint Sheldon's directions.
There are dozens of chain guides available. If you use the BBS outside chain-guard, you'll only need a simple 'proximity' guard on the inside of the ring such as the 'Chain Keeper' or 'Chain Buddy' or whatever it's called. There are a few good nylon ones available or it's dead easy to make your own. If you don't use an outer guard ring, you can use a chain guard like the Paul witch fits over the top of the chain itself. There are plenty of this type available although the Paul seems to be well regarded. Again, you can easily make one too. Or use a 'locked' front derailleur!
As I have inferred in a post above, I use eride's chain ring adapter which is nicely made, reasonably priced and doesn't (for me) entail paying the crazy postage costs encountered for anything sent from the USA these days. Eride is a gentleman named Finn who lives in Denmark.
Mind you, I am only using my BBS01 on a small travel, 20" wheel, suspended URT frame. If a more powerful BBS is used on a long-travel bike with maybe a non-URT, small-chainring arrangement over rough ground (and jumps) who knows what chain management apparatus you may need! http://endless-sphere.com/forums/posting.php?mode=quote&f=28&p=886075#
Savvas
Savvas.
tomjasz
1 GW
Is the Pashley a 68mm?samsavvas said:
Thanks Sam!
joshseitz
100 W
If using a 130mm BCD adapter and chainrings, would it be possible to place the chainring and some spacers inboard of the adapter to bring the chainline back where it should be, or will the drives body not fit within the circle afforded by the 130 BCD ring? If that makes sense...
xpc
1 mW
Lesson in metics for tomjasz,
take an inch x 2.54 = mm
take an inch x 2.54 = mm
samsavvas
100 W
tomjasz said:
Yeah - I'm in my 60s too but have been fortunate enough to have grown up with both Imperial and Metric standards. Please forgive me - maybe I'm just 'accuracy focused', but no matter. Maybe what you can add to your list is that all Pashleys, being mostly traditional steel bikes made for IGHs (or smaller rear sprocket counts), will have 68mm BB shells. This goes for all similar bikes, both old and new. The wider 73mm BB shells are generally used on bikes made with fat seat tubes or designed to cope with higher sprocket # cassettes (ie; 8-10).
Given the way the BBS works and in terms of chainline management, if you are using a non-dished, after-market chain-ring arrangement it seems to me that the best candidate frames for BBS use with a rear derailleur will have a 135mm rear OLD and a narrower 68mm BB. Which implies for me a good quality '90s mtb with a 1" or 1-1/8" seat tube. This would maximise your chances of 'centering' the chainline on the cassette.
I think similar numbers may be ideal for BBS use with an IGH or coaster (neither of which I've tried) although of course you can fiddle things a bit in this case by reversing the (usually) dished rear sprocket.
What I have found is that frame construction can also be an issue. On some of the frames I've tried to fit the BBS to (at least 2 of those favourites hanging in my shed anyway) the use of round (as opposed to ovalised) chain stays and a socketed BB shell has made the space just to the rear of the BB too crowded for the BBS's main gear case without use of a spacer or a big hammer. Thus far a 1.5 or 2mm spacer has solved this issue, but this of course places the chainring even further out to the right, requires more washers for the 6mm yoke screws on the left and reduces their thread engagement (the female casing threads are easily stripped - don't ask how I know this!) This may all become an issue if fitting the BBS to steel, double-chainring road frames which often used really beefy round chainstays. The hammer treatment looks attractive in such cases!
I do wish that Bafang would publish some 'ideal frame' information for their units. But I guess that would spoil the adventure a bit!
Savvas.
samsavvas
100 W
joshseitz said:
I'm actually going to try this shortly on my 20" bike with one of eride's 6mm rebated adapters which he's sending me. There are two or three issues that I can see:
- the adapter ideally needs to have it's inner face as close as possible to the BBS main gear case (eride seems to have managed this with a large, central milled rebate)
- the adapter arms need to allow the chainring fitted on the inner face to clear the gear case (again, eride seems to have accounted for this with rebates milled into the ends of the arms).
- I may also have to ensure that the chainring is oriented with its rebated bolt-holes facing the gear case to ensure that protruding chainring bolts don't foul on the gear case.
I have already got one of erides non-rebated 3mm adapters. I'm not sure that the 6mm machined one will be better but we'll see. I would like to see my 60T ring more centrally located, although as I've said, I don't experience chain-loss problems anyway. I do have my rear derailleur (an old Suntour Cyclone 7000 medium length) adjusted so that the chain is never 'loose' and the chain ring has no ramps or other rubbishy features.
I'm also going to try the BBS on a 700C bike with a 5 or 6 speed cassette and a Sachs Orbit 'dual drive' 2-speed rear hub. The hub and bike in question have a 130mm rear OLD/spacing and a 68mmBB width. I'll just use the standard BBS dished 48T ring first up and see what transpires. Should be interesting (you can see I'm easily pleased although some may call it 'cheap thrills').
Savvas.
teslanv
1 MW
Sorry xpc...xpc said:
1" = 25.4 mm or 2.54cm
xpc
1 mW
you are right teslanv, was trying to be a smart ass, but backed fired.
xpc
1 mW
Tomjasz, you will need to ask greenspark this question, send him a pm
tomjasz
1 GW
We can, seems like this would be a good place to begin to collate that data. I would like to invest the time to do exactly that. I'm sorting through hundreds of pages in an attempt to collect info.samsavvas said:
I'm thrilled with this drive. I created a retrofit nightmare on my choice of frames, but am tracking towards a second bike. So far my personal leader is a FF Electra with disc brakes. Sadly it's balloon tired. My dream ride, a FF frame, disc brakes and an 8 speed IGH. I'm amazed at how easy a shifter my Nexus 3speed is. A bit of a learning curve but I'm grinning ear to ear. Not unlike the first years of my Vespa GTS. It fits my lifestyle and physical constraints. AND the kit will fit a tricycle next, OR a city bike, or a MTB or a....
We/I just need a list to make the process easier for those joining the fold. The more the merrier and as a benefit better support and parts access.
This ride is so quiet. Especially when the HA's are on the dresser.
I expect to order another BBS01-2 by Monday. I'm just fretting over which. 350, 500, or 750. With the 750 my budget means a 10ah battery. Then again there are sustainability/parts supply advantages to two identical units.
Then lere's the friction drive or the Lime. This stuff is like crack.
Best,
Tom
I did a new video...https://www.youtube.com/watch?v=RK38Nw_KNmY
teslanv
1 MW
Xpc,xpc said:
Please don't think I was being a jerk about it or anything. I think most people would have caught the typo. Some would not, though, so I thought it best to... Clarify.
amigafan2003
1 kW
My BBS02 48v500w equipped full sus going down Hully Gully at Gisburn, Lancashire, UK
[youtube]0YsKVdIMj-0[/youtube]
[youtube]0YsKVdIMj-0[/youtube]
Rollodo
1 kW
How do you guys figure the wattage of your BBS? My C961 doesn't show any watts at all.
amigafan2003
1 kW
Rollodo said:
I use a Turnigy watt meter - fyi my BBS02 48v500w peaks a shade over 1100watts.
majornelson
100 W
tomjasz,
Does Electra make the FF? I think I may have missed something earlier in this thread...
tomjasz
1 GW
Maybe my miss use of FF. Flat Foot in another forum. What is it here?majornelson said:
samsavvas
100 W
tomjasz said:
I believe that 'Flat Foot' is just Electra's attempt to define and appropriate their own 'leadership' profile for the crank-forward design. That's my view anyway. It's not a major crime or anything - just standard 'marketing speak' and spin.
My personal view is that it's more correct to adopt long-held terminologies. Better for everyone in the long term. If your use of 'FF' is referring to the key feature of most Electras - the location of the BB a few inches in front of the seat post alignment - then you are talking about a 'Feet Forward' bike. The same terminology is used in the motorcycle world.
Personally I'd not previously heard FF used as shorthand for 'Flat Foot'. I'd always known the Electra as a 'crank forward' design because the cranks are in front of the seat tube termination. But given getting your feet flat is one effective outcome of this design, I suppose it would be a reasonably valid use of the term and not one I'd argue with.
However there are at least two other good reasons for sticking with reference to 'Feet Forward' as a better description of the design (despite there being at least two approaches, differing simply on whether the seat tube terminates at the BB, like a Flying Pigeon, or behind it as on the Electra).
One reason for FF is to allow a wider range of rider-leg lengths to fit a given bike size. Examples of this might be those bikes with very 'slack' but conventional seat tube alignments, like the Rans semi-recumbents, the Danish 'sofa' bikes and some childrens 'grow' bikes. The 'higher' you raise the seat and move it away from the pedals to allow for longer legs, the longer the cockpit becomes to allow for corresponding long arms!
The other (and my personal favourite) design objective for many Feet Forward designs is that - by retaining both an upright position and facilitating a bit more bend at the hips - you get an upright, relaxed bike that you can still pedal vigorously against a headwind or up a hill without getting out of the saddle, the increased angle of the hips allowing the powerful gluteal muscles to contribute effectively even though the rider is not in 'racing' position. That's the theory anyway and the reason why very old bikes from the 1900s and many modern Indian, Dutch, German and other traditional designs (and even some early mtbs) also have ultra slack seat tubes. It's a very sensible approach if you don't go much faster than 20km/h on the level most of the time and don't have to worry about wind resistance. Or if you don't have a bit of 'assist'...
I too have thought the Electra would be a good candidate for electric-assist, especially with a proper torque-sensing PAS system.
Sorry - another rant I'm afraid. I'm a frustrated physicist!
Savvas.
ps; 'Bicycle Science' has a good chapter on seat tube angles and 'FF' outcomes.
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