DIY stage 8: Continuous improvements...

[jerrysimon]

If you look at Sheldon's web site here on the wheel page build about half way down after the first group of spokes have been placed in both sides, he states

"Turn the wheel back around so that the freewheel side is toward you. Insert a spoke into any hole, but this time from the inside of the flange. Twist the hub clockwise as far as it will conveniently go. Since we are building a cross 3 wheel, this new spoke will cross 3 trailing spokes that go to the same flange of the hub."

BTW I checked my Tongxin rim on the Cytronex and the holes are countersunk on the hub both sides so the bend angle is not effected no matter what way you put the spokes in

Regards

Jerry

 

[daniel.weck]

From ES, some good links to YouTube videos:

Endless-sphere.com • View topic - For Beginners: How to Build a Wheel

Yes, we spotted these videos before. No need for an ES account:

YouTube - How to build a bicycle wheel - Part 1 36 Spoke

Cheers, Dan

 

[daniel.weck]

"Turn the wheel back around so that the freewheel side is toward you. Insert a spoke into any hole, but this time from the inside of the flange. Twist the hub clockwise as far as it will conveniently go. Since we are building a cross 3 wheel, this new spoke will cross 3 trailing spokes that go to the same flange of the hub."

Yes, that's exactly what I meant with my "little" explanation
Just like I said though, double-check that the nipples are fully engaged through the double-walled rim holes.

++
Dan

 

[jerrysimon]

I think my Cytronex wheel is non standard ?

Sorry Dan I kinda hijacked this post for wheel building lol

Anyway after a lot of reading and head scratching I think I finally understand. What was confusing me is I think my Cytronex wheel spoking is incorrect or at least non standard.

The picture shows the wheel pointing forward to the right wheel rolls clockwise. The other confusing part is that on the Tonxin motor the cable exits from the left (non drive side) looking down when seated on the bike whereas on your Bafang it exits from the right (drive side).

Now look at the trailing spokes (those going anti clockwise) they are connected to the outside of the hub rim not the inside ?

Everything I have read has said trailing spokes should connect to the inside of the hub flange ?

Here is a closeup

Regards

Jerry

 

[daniel.weck]

Yes, in this case the trailing spokes exit the hub from the outer side of the flange. I don't think it impacts the reliability/efficiency of the wheel, but I find that it's easier to do it the way advocated by Sheldon Brown and others, due to how spokes need to be adjusted/bent manually to exit the hub flange at the optimal angle in relation to the rim hole (and then interlaced, for anything other than a radial arrangement or a 1-cross lacing pattern). As long as the right side is consistent with the left side...I'd say it's totally safe.

 

[daniel.weck]

By the way, your Cytronex's front wheel is laced into a 2-cross pattern, and you can clearly see the interlaced spokes: if you follow a single spoke and start counting from the hub towards the rim, it's the last/second spoke to be crossed.

 

[jerrysimon]

Thanks Dan.

I have to say this spoke pattern/lacing thing has had me tied in knots. I must just be getting old

PS Yes Dan I noticed that over under and under over depending on which side of the rim it comes out of.

Regards

Jerry

 

[emissions-free]

Jerry,

most hub motors have the cable exit on the left side as per your Togxin. Bafang is quite unusual in that all their hub motors have cable exiting on the drive side (right side when you are sat on the bike).

I also found the lacing pattern a bit of a head twister and managed to repeat the same mistake twice on 2 different wheel builds. It definitely gets much easier with a little practise, but I still need A LOT more practise

 

[daniel.weck]

Statistics, statistics....

Another charge cycle today, another set of statistics from the Cycle Analyst (the fourth). I see a trend emerging, which is great because I am now able to plan future (longer) trips with a pretty good estimate of when I would run out of battery

I'm thinking of a trip down to the south coast later next year (and up again: 60 miles or just under 100km), and there are good hills on the way back, so I'd better plan carefully I would probably stay over for the night, it's not a race, so plenty of time to recharge the energy levels (me and the battery ).

Based on my typical usage pattern -- 50% moderate hills, some load on the bike (shopping, tools, etc.) -- my Bafang motor consumes (rounded values) 2.25Ah from the battery per 10km, which is about 180W/h or 8Wh/km. My LiFePo4 battery being rated 10Ah at 1C, that's 44km on one charge (at least). My peak current draw is around 11 Amperes up the hills, so not much over the basic C discharge rate. I guess I could easily ride 50km and still have juice left in the battery, providing the peak energy demand (i.e. moderate/strong ascents) correspond to not more than 50% of the journey.

I'm quite curious about the Tongxin motor actually, as it's a pretty slow one (190rpm for my 16" wheels means it won't give me the Bafang "kick" that I get up to 260rpm). But that could be an advantage in terms of lowering the energy consumption (180W rating versus 250W for the Bafang, continuous of course). Yeah, lots of unknown parameters, so I'm looking forward to giving the Tongxin the Cycle Analyst "treatment"

Cheers,
/Dan

 

[cirrus18]

Based on my typical usage pattern -- 50% moderate hills, some load on the bike (shopping, tools, etc.) -- my Bafang motor consumes (rounded values) 2.25Ah from the battery per 10km, which is about 180W/h or 8Wh/km. My LiFePo4 battery being rated 10Ah at 1C, that's 44km on one charge (at least). My peak current draw is around 11 Amperes up the hills, so not much over the basic C discharge rate. I guess I could easily ride 50km and still have juice left in the battery, providing the peak energy demand (i.e. moderate/strong ascents) correspond to not more than 50% of the journey.


Cheers,
/Dan

The distances you are getting sound quite good but they do depend on how much effort you put into peddling and how much you use motor assistance. Would you please explain a little how much effort you are putting in.
Do you use the throttle, if so how much, or do you use the three position switch, if using the switch, what setting do you use most of the time, position 1, 2, 3?
Do You have motor assistance throughout the entire ride or just occasionally?
I am interested because I have the same setup as you but with a 15 amp hour battery and was wondering what sort of range I could expect to get.

 

[daniel.weck]

The distances you are getting sound quite good but they do depend on how much effort you put into peddling and how much you use motor assistance. Would you please explain a little how much effort you are putting in. Do you use the throttle, if so how much, ...Do You have motor assistance throughout the entire ride or just occasionally?

I'm not a strong cyclist (under 70Kg), but I like to be constantly "pushing", with downward and upward pedal strokes. I get bored if I don't feel the human effort (i.e puffing + sweating ).

Baring in mind that the assistance is available up to about 24km/h, and that I do 20km/h average, 40-50km/h max downhill:

I normally let the Pedal Assist Sensor control the motor power output, which means that I must maintain a high cadence to get rewarded with this "bionic leg" sensation. I'd say that the assist is on most of the time, albeit at low levels (I notice the difference when the assist if off, I can feel the extra weight and drag of the e-Brompton!). I don't keep my eyes on the Cycle Analyst display, but I think between 40W and 200W is provided most of the time up to the legal speed limit (which I believe is a technical limit in my case, not a setting I can override). Anything between 200W-400W is what I would call "serious" assistance, only occurring when climbing. I must double-check these figures though.

Sometimes I have less stamina, so I prefer to crank-up the throttle and use a low pedal cadence / high torque. I will sometimes stand on the pedals to climb serious hills, but to be honest most of the time high-cadence works fine at 400W/12A peak. The Bafang is a great climber, no doubts about that, but not when used like a moped !

I mostly use the throttle to take-off from a standstill (whilst pedaling of course), it is a really helpful feature, especially in traffic.

I have just purchased Power Grips to transfer leg power more efficiently into the pedals, this should help me keep the battery consumption down. See here: http://www.pedelecs.co.uk/forum/electric-bicycles/5132-its-cold-dark-windy-raining-never-mind-2.html#post65651

or do you use the three position switch, if using the switch, what setting do you use most of the time, position 1, 2, 3?

1: when I have to be "careful" (when I "walk the bike", very slow traffic, pedestrians wandering around, etc.).

2: slow-moving traffic, starting from standstill (with throttle help).

3: most of the time.

I am interested because I have the same setup as you but with a 15 amp hour battery and was wondering what sort of range I could expect to get.

15Ah LiFePo4 from Li Ping ?
Bafang 255rpm ? (the gearing probably affects the statistics, depending on the terrain)

Cheers, Dan

 

[daniel.weck]

short video clip

My typical "touring" configuration:

YouTube - Brompton luggage high-visibility yellow rain covers

(make sure to turn on annotations for this YouTube video)

 

[daniel.weck]

"Steep Road"

I though this was funny !

Short video: YouTube - eBrompton and "Steep Road"

 

[daniel.weck]

Talking about hills, here's a moderate one and my attempt to capture the event with a handheld video camera (my fingers tips were freezing !):

YouTube - eBrompton going uphill, handheld video camera