Learning Curves Bafang BBSO2

With the BBSO2 installed on Rover II the real lessons begin. Curiosity killed the cat. What will it do to Rover II's chain line? Let's review the goals

1. I want to cruise comfortably regardless of headwind, hills, or hard rolling resistance without wrecking my knees
2. I still want a comfortable but reasonable amount of exercise. As long as the pedals go round my leg muscles are gaining
3. High speed is not a goal with 20-30 kph on the open road  reasonable for my area. The legal e-assist speed in Ontario is 32 kph.However you can coast as fast as you want unassisted. In Minnesota its 20 mph e- assisted or otherwise. 
4. I want to meander along at 10-15 kph on the walks and trails in town where there is significant pedestrian traffic
5. I want to be able to go further, finding over 35 km per trip on my home route unassisted is about all my knees will tolerate.  50 to 70 km on a charge would be nice.

My kit included a new 750C colour display. It was just released and like most things e-assist, instructions were scant. A link on the Luna Cycle Forums https://electricbike.com/forum/forum/ask-lunacycle/luna-cycle-new-products/32467-new-750c-color-display-for-bbshd-and-bbs02 got me started. This display has a few bugs and shortcomings I hope will be addressed by a firmware upgrade in the near future, but on the whole it seems decent. I have not changed any of the controller settings that came with the unit. They are the stock settings as supplied by Luna. I have a programming cable and will look at them in the future.

The main screen combined digital and graphic displays provide an uncluttered easily readable info on speed, watts consumption and assist levels. Smaller print provides more info on trip, odometer, battery level, time and other items you would expect on a bike computer. There are some issues with glare under certain conditions, but still generally fine for me. Navigating around the computer brings up a whole bunch of info I do not understand and is not yet active for the BBSO2.

The one main change I have made is to the E-Assist Levels. I changed it from the default 5 to 9. This fit my route conditions and my style  better. Now in Level 1 power consumption appears to be around 90 watts and for much of my paved route without a headwind I run in 6th gear at 21-23 kph.aiming for a cadence of 60-70 rpm.With a stiffer headwind or grade I go to Level 2 and appear to be drawing 170-190 watts, Really ugly northwind the other day, I went to Level 3 drawing about 300 watts. Don't know how accurate that watt readout is and it bounces around a fair bit you look for an average.

I also changed the speed limit assisted maximum to 32 kph to be in accordance with Ontario law. It does work and interestingly the throttle assist only increases the speed to that max. Also higher e-assist levels will draw higher watts up to the speed limit and then cut back to lower watts. The level seems to 'hunt' for proper wattage when you are against the upper speed limit, but is more stable when 3-4 kph below the max. Hmmm?

On a bit of a down grade with a tailwind I use Level 1 in 8th gear running  29-31 kph with a 65-70 cadence. Again wattage drops way down at 31-32 as no load.(There is no cadence readout on this computer I just calculated  using BikeCalc.com) Here I may do some coasting and stop cranking in which case the power assist stops and you pump again when you want/need it.
I've found setting the lower level of assist now in Level one more my style when riding slower on variable gravel road surfaces, even running in a lower gear.

Shifting and pedaling with a PAS e-assist rather than a torque sensor like in the Tongsheng TSDZ2 or some of the other OEM mid-drives i.e.Yamaha. Bosch is described as a little different, but the essentially the same problem. (No personal experience on other systems) You don't want the e-assist pumping out power when you are trying to shift.

On the BBSO2 this is easily accommodated , particularly on a trike. Some use a gear shift sensor, but I think they are wholly unnecessary on a BBSO2. Think of it as driving a stick shift particularly truck carrying a heavy load. When you pause pedaling the chainring stops (it's right in front of you and very visible) as power to it is shut off, and will not start until you resume pedaling. Shift your gear- up or down- and turn the pedals a little bit -sixth or quarter turn- and a little shot of power will spin the chain ring a bit pulling the chain through the rear derailleur smoothly without undue stress on the chainline as you have only momentarily sent power to the chainring. You cannot of course change gears at a complete stop or under heavy load without the 'crunch' on the rear sprocket, just like you cannot engage gears on a stick shift under heavy load or at a full stop without  properly using the clutch. Sound complicated? It's not.

Never operated a trike with a Nuvinci hub, but bet it would be sweet with this e-assist.

Finding the proper cadence is important on I believe all e-assist, as DC motors have efficiency curves. The BBSO2 'sweet spot' appears to be in that 60-70 rpm cadence. Maybe even faster but I find higher cadences uncomfortable and subject to fishtailing. Certainly 20-30 rpm cadences don't feel like they are putting out power comparable to what the watt meter is showing.

								Speed KM per Hour				at Cadence			24" Wheel
Gear	Cogs	5	7	9	11	13	15	17	19	21	23	25	27	29	31	33	35	37	39
8	48x11	10	14	18	22	26	30	34	38	42	46	50	54	58	62	66	70	74	78
7	48x13	12	17	21	26	31	35	40	45	50	54	59	64	69	73	78	83	87	92
6	48x15	14	19	25	30	35	41	46	52	57	63	68	74	79	84	90	95	101	106
5	48x17	15	22	28	34	40	46	53	59	65	71	77	83	90	96	102	108	114	121
4	48x20	18	25	33	40	47	54	62	69	76	84	91	98	105	113	120	127	134	142
3	48x23	21	29	38	46	54	63	71	79	88	96	104	113	121	129	138	146	154	163
2	48x26	24	33	42	52	61	71	80	90	99	108	118	127	137	146	155	165	174	184
1	48x34	31	43	56	68	80	93	105	117	130	142	155	167	179	192	204	216	229	241

In town when I don't want/need e-assist, I simply reduce to Level 0. The freewheel clutch in the drive motor incurs no drag as nothing in the motor is turning. Do not notice any difference in pedaling resistance between this and a simple bottom bracket.

The BBSO2 has a Thumb variable throttle control I rarely use. It has amazing torque that would certainly shorten the chainline life and perhaps the internals of the BBSO2 as well as the battery range if used injudiciously. But it is always available regardless of Assist Level as long as power is on. occasional boost going up a hill. Very handy for spinning the chain line when I have the trike suspended and setting up the shifting on the rear derailleur. On a test across a level strip the trike would quickly spin up over 30 kph, but was drawing over 900 watts so would quickly drain the battery.

Ride is as smooth with 20.5x2.12 Big Apple fronts and 24x2 Knobby rear. In fact it seems as good at 25 kph as it was at my humble 15 kph I used to ride unassisted. it is virtually silent, with the knobby rear tire and the chainline tubes providing the most noticeable sound. Gravel roads are readily navigable, with the only caution really loose gravel and washboard.

Range. Not sure yet. I have done 50 km on a combination of gravel and tarmac roads with a bit of grade and some headwind. Voltage showed I was down to 46.2 at end of trip. Battery voltage 'sags' during operation and then rebounds a volt or two after a few minutes rest. Motor gets barely warm to the touch sometimes and battery case not at all. I have been charging the battery in slow mode to 80 or 90%capacity with the occasional charge to 100% as recommended.

The Purist goes E-Assist

I have been looking at E-Assist and after experiencing the Hills of Osoyoos last winter, I finally pulled the trigger and bought a Bafang BBSO2 Mid Drive kit from Luna Cycle. It arrived in April. The decision to go with the BBSO2 and Luna rather than an alternative was decided not so much on price and features, but on availability of  consistent reputation, parts and options.

One Karl Gesslein of https://electricbike-blog.com/ has spent the better part of the past two years and a small fortune doing his very best to destroy every e-bike motor including the Bafang BBxx models offered. His exploits on e-bikes are perhaps bordering on the insane. If a mid-drive e-bike motor can survive his torture tests, they should serve the normal person very well.

Educating yourself is a must, with no end of resources. As well as Karl's blog there are several others. Two I would recommend are electricbike.com, which is run by Luna Cycles a Bafang distributor and another Electric Vehicle and Technology Forums endless-sphere.com. Both are a wealth of information and opinions. You will need the resources they offer. The Power Assist  forum on BROL is also great

Ordering my BBSO2 kit from Luna was fairly straight forward, but I did not know what options I would need to mount it on a Rover trike so I only ordered a longer main harness, an upgraded battery charger, and a speedometer cable extension, opting to start the installation and then order additional cables after I measured things up.

Taylor at TerraTrike found me a spare Rover boom in his surplus inventory for $95 which I thought would be handy in that I could premount the Bafang drive without having to take out the bottom bracket and chainrings. If I ever wanted to switch back either permanently of temporarily (meet with no e-assist allowed) I could do it in a matter of minutes.

The beautifully packed Luna box arrived UPS as promised. I opened it, unpacked eveything and spent the next half day scratching my head and wondering what to do first. There was not a scrap of instructions. Not one of the various packages of parts and cables had a label on it. The grey matter had to do some extra work. It really was like the first day of school.

I mounted/dismounted the drive on the front of the boom a couple times. Slept on it and then did it again. Could it possibly be this simple?

Mounting the battery was a conundrum. I finally decided crossways behind the seat against the rear fender would provide the best weight distribution -about as far behind the front axle as the drive was in front of axle. A couple of pieces of 3/4 in plywood, my router to make an mounting notch, some wood screws, and a couple of heavy gear clamps made a solid platform for the quick release battery bracket. I used similar hardware arrangement to mount my Windwrap faring. It is solid, reasonably light and just works!

I put the boom with the drive through the crciform and into the frame tightened the grub set screws, and started measuring and plugging it wires. It went pretty well.

• I needed a power cable extension 22", a piece of HD ext cord soldered in- done
• speedometer ext was too short rather than order another I cut and extended with Cat 6 network cable using 3 of the twisted pairs to extend. Worked.
• installed speedometer sensor on left rear. straight forward

• plugged in over-length harness and routed along boom to cruciform and up left steering arm.
• Mounted throttle control and main control switch to left handle bar. Crowded but ok.

• Mounted Display computer to an accessory bar I previously used for cell phone. OK for present.
• Epoxied magnets for the Hall sensor brake power cutoffs to both brake handles. Took three views of different YouTube videos to figure that one out.
• Stuck Hall sensors on brake lever bodies.They have self adhesive pads. Works ok
• Plugged in left brake sensor. Works OK
• Right brake sensor requires extension cable which I must fabricate myself if I want.(don't think I will need it) About 24 inch. Cat 6 as with speedo cable would work fine.
• Zip tied the wiring up in place. Charged the Battery, Plugged it in. Nothing blew up or smoked. Played with controls and took for short run.
• It works flawlessly and very quiet.

Rover II E-Assist ready for first test run

The working installation is complete, but I have a number of things to refine. I need to tidy up the wiring and seal the connectors. I will redo the power cable extension as it is too long. The battery mount is fine but I need to put some stain and sealer on the wood. The wires down the main boom are shrink wrapped at the joints but I will put some loom over it to tidy it up. A better mount for the display is in order.

So how does it work. Fine, But lots to learn. However I no longer dread stiff headwinds or towering hill. And my knees are very happy. Details in next post

Down & Dirty

Some folks buy new trikes, or cars,,, so they can sit in the driveway nice and clean and shiny, looking pretty. On the other hand I get them to ride. "Wear 'em out!" is my motto. And I must admit that includes a modicum of abuse.With Rover II topping the 7000 km mark over this past year it was time for some serious spring maintenance.

The past winter in Osoyoos, BC with its attendant well salted roads, giant hills, and lack of dry, heated storage to carry out maintenance took its toll on Rover II as well as me. A bunch of sprocket crunching shifts when the slope overcame my reluctant leg muscles did nothing to pamper the driveline. And although I had some replacement parts, I put things off until I returned to Rainy River where I could work in the comfort of my own cluttered workshop.

(I had been considering some e-assist and in March pulled the trigger on a special Luna featured on a Bafang BBSO2B package, but more on that in my next post)

As well as rolling under my power for 7000 + km Rover II had spent a lot lot time and miles travelling back from Florida, across Ontario, and twice back and forth across most of western Canada. I can't imagine a worse spot for sucking grit, grime, and moisture into every nook and cranny of a trike, than on the back of a vehicle. Maybe it's time to invest in one of those hermetically sealed trike coffins that fits on the rear hitch.

After a thorough wash at the coin-op, I started to pull Rover II apart. I dropped off my Windwarp fairing and set all the bits and pieces carefully in one tray... it may not get put back on until next fall.The chain came off and was quickly consigned to the scarp heap...definitely shot.

After removing the seat (mine is tight and never goes out of adjustment), next I backed out the grub screws on the frame. Easy, peasy as I had forced grease into every one last spring after reading on the forums the joys of drilling our seized set screws.

Then slide the main boom out of the cruciform and rear frame. A pull, then a wiggle, and a stiff jerk yielded no results. Checked to make sure  all the set screws were out. Yep! A piece of hardwood plywood against the boom behind the bottom bracket and a couple of stiff blows with a two lb hammer started things moving. Took a few more to finally get the boom out. The amount of surface corrosion in the cruciform and frame was quite extensive, so I cleaned things up and poured some heavy oil through the interior to coat everything and made sure I coated the boom with heavy grease before reinserting it. Everything now slid together smoothly.

Corrosion on boom after one year: ridden 7,000km. transported 11,000 km

Rover II: Upside down and Apart

I did a thorough examination of the weld under the cruciform and frame. Everything looks fine with no sign of bends or cracks. The bearings on the front wheels and the bottom bracket seem excellent so no further action there.

The rear sprocket was, well, trashed... crunch, crunch, once (many times) too often. Replaced it with a Shimano HG31 8 Speed Mountain Bike Cassette (11-34T) Sold by: Sun Cycle Warehouse $17.77 which I had bought last year but never installed. Wish I had as I could have used that 34T low over the stock 30T on those Osoyoos hills. The rear bearing seems fine so cleaned and lubed it and checked the spokes for tightness... a few took a half turn and rim is straight. I'll leave the knobby winter tire on for present as I want to try some gravel roads.

The derailleur was a mess and looks pretty worn. I decided to order a new one as they are less than $20 MicroShift Mezzo Long Cage 8/9 speed Rear Derailleur, Sold by: Gap30Cycles, $18.65 from Amazon and in meantime pulled the old one apart, cleaned and lubed it and reinstalled. It works.

I had a spare set of brake pads I ordered from Taylor at Terra Trike in the winter so decided to put them on. Some wear on the old ones but not that bad. More a case of uneven wear rather than loss of performance. See lots of suggestions in the forums claiming BB7s are far superior to the stock Alhonga brakes, but I have never had a problem with Alhongas... easy to adjust and perform adequately. Changing pads and readjusting is a bit of a fiddly experience, as are working on derailleurs. A few points: a: work on a well lighted comfortable surface, because you will drop parts, your eyesight just ain't what it used to be, and your physical stamina is limited. b: watch the YouTube videos and bookmark them so you can find them again, because you will forget proper procedures and dyslexia is far too common to depend on written directions. Found a couple places on Rover II that used Torx screws rather than Allen heads. so be prepared.

Checked out my lights and chucked my Bell white strobe that has been taking on moisture and no longer takes a decent charge. Put on a new front white strobe c/w a pukey little horn (but legal now)

Put together the three SRAM 8 speed chains I had purchased from an LBS in Osoyoos last winter and with trusty chain tool took out the excess links. Put the seat back on and took Rover II out for a spin.

JOY!!

Details on the BBSO2 install next post

Note: As an aside I buy as many things from local suppliers as I can, but I don't have an LBS and Amazon, is generally priced competitively with delivery to my door in usually two days or less. Good service deserves a nod.