The Pusher

[51owRider]

If you could find a small dd . I love my dd regenerative. It is my only rear brakes. I only run 16 mph though. It will throw me forward a little. You may have traction issues though. Unless you can adjust it. Trailer brakes would be the bomb...

I ruled out DD because of the drag when not powered and the extra weight, I might be wrong, but I'm a total newbie to electric bikes at this point. I recall reading about features similar to traction control and ABS being available on some advanced controllers.

 

[51owRider]

Wireless...can be done, but test to ensure LOS = system shutdown. Don't want uncontrolled runaway operation because the head control unit battery died or someone with an overly powerful CB/ham/etc radio CQd as they passed you.

Of course, safety first. I'm fairly proficient programming microcontrollers, the wireless will be over BLE on an ESP32 with a short timeout and will give the controller a PWM signal simulating a throttle potentiometer. I've built some powermeters and cyclocomputers on the ESP, for anyone interested: https://github.com/gsoros/ESPM and https://github.com/gsoros/ESPCC .

 

[51owRider]

Just remember if you end up TIGing the extensions to the frame, you may need to re-heat-treat the frame and extensions to regain the original strength.

Good point. Although, the dropouts are quite thick, I could lay down some hefty over-engineered beads, but it's probably safer to find someone with a big enough kiln.

Optionally you could build a secondary frame with dropouts on it, including it's own triangulation, that is shaped to match the top of the trailer frame's dropout and rear frame section, then you can use clamps of the appropriate type to secure it to the frame.

It's an oddly shaped thin-wall hollow-section, don't think clamping is a good idea. I could drill it and use rivnuts, also not ideal for structural stuff... I'll think about it.

Thanks and please give a Jelly Bean a good belly rub from me.

 

[amberwolf]

Of course, safety first. I'm fairly proficient programming microcontrollers, the wireless will be over BLE on an ESP32 with a short timeout and will give the controller a PWM signal simulating a throttle potentiometer. I've built some powermeters and cyclocomputers on the ESP, for anyone interested: https://github.com/gsoros/ESPM and https://github.com/gsoros/ESPCC .

Thanks--maybe at some point I could conscript you to help with some little projects here and there like the Nano Tidbits stuff when I eventually get back to those (and one relatively large (to me) robotics-related project that I am still working out what it has to do exactly).

Good point. Although, the dropouts are quite thick, I could lay down some hefty over-engineered beads, but it's probably safer to find someone with a big enough kiln.

I'm not experienced at anything other than steel-welding (and certainly no expert at that ), so I don't know if that will compensate for the change in strength of the areas around the weld itself (I don't know how large the HAZ would be, but I expect fairly big given the capacity of aluminum to quickly re-distribute heat).

It's an oddly shaped thin-wall hollow-section, don't think clamping is a good idea. I could drill it and use rivnuts, also not ideal for structural stuff... I'll think about it.

I used hose clamps to secure thinwall aluminum tubing ex-sleeping-cot sections together to keep the SB Cruiser's canopy in position against all the gusty winds and whatnot it experiences, and the cantilevering torque. It's also got bolts thru the tubes into the rear over-cargo-deck frame made of the rest of the cot. It works, and doesn't loosen, but I don't expect it sees the same loads yours will.

However, if the clamps are of sufficient surface area, and there are enough of them, they'll distribute the load over enough tubing to reduce the risk of any damage to any specific areas. Myself, I don't think it's a risk, but I dont' have your trailer there to examine, and I am not a mechanical engineer (just an experienced hack with decades of (mostly) successfully misusing things for other purposes behind me :lol: ).

My personal experience with rivnuts in things other than just securing non-structural cover plates to "boxlike structures" has been less than stellar, whether they were preinstalled or I did them, but that's just as likely to be a user problem as a design/materials one.

Thanks and please give a Jelly Bean a good belly rub from me.

Jelly Bean the Belly Bean will appreciate that. She's presently upside down at the end of the bed snoozling...

 

[51owRider]

Thanks--maybe at some point I could conscript you to help with some little projects here and there like the Nano Tidbits stuff when I eventually get back to those (and one relatively large (to me) robotics-related project that I am still working out what it has to do exactly).

But of course, anytime!

 

[51owRider]

Just a quick update, finally got around to realize this project over the holidays. The fork extension is made of stainless steel tubing with tool steel inserts at the end where the holes for the hub axle were drilled/filed. A custom rear fork with suspension is in the works. The hub is an MXUS XF15, I wanted something lighter like a Q100 but now quite happy with it, it delivers nice amounts of power pushing me and the cargo uphill while barely getting warm to the touch. We'll see in the summer, I can always add a thermistor if necessary. It is driven by a Flipsky 75100 which is controlled over BLE in PAS mode only. The battery pack is a 13s7p 18650 Samsung 29E with a 30A BMS, I'm planning to build a second identical pack for the long journeys.

Some pics, excuse the dirt, can't be bothered to wash the bike

 

[amberwolf]

Looks good.


As long as the dropouts/toolsteel inserts are such that the torque from the tiny axle flat contact areas can't cause the axle to rotate within them, it should be ok over time. The wider the dropout / insert flat face that holds the axle are, the greater the surface area contact between them, and the more torque that can be transferred from axle to frame (and so the harder the wheel can push against the ground).

 

[999zip999]

Yes how are the 10mm flats on the axle held in place or how is the axle supported not to spin with the motor. Aka torque arm ?

 

[51owRider]

After flattening the tube I hammered in a tight fitting piece of flat tool steel approximately the length of the flattened part. Then I drilled the hole for the axle to 10mm, then I filed the hole to 10x14mm to fit the axle plus the toque washer (which is on the inside of the fork). Repeated for the other side. So basically the torque arms are inside the fork tubes. Hopefully they will hold up. Here is a pic with the washer removed:

 

[amberwolf]

Something to consider when designing the replacement suspension setup: If the torque is high enough, you might run into issues where the hard tool steel cuts into the (probalby softer) axle metal. This can happen in those cases:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=26444&p=1746140#p1746140
https://endless-sphere.com/forums/download/file.php?id=328959


and can be minimized with a much wider (as much as possible) contact surface area between the axle flats and the as-perfectly-fitting-as-possible dropout/torque plate. (a clamping style dropout is perhaps the best way to make the tightest fit; there are numerous examples in above-linked Torque Arm Picture Thread if you need to do that).

 

[999zip999]

I always use Norlock a type of spring loaded lock washer. To narrow of a T.A. has cause me trouble also cutting into the axle.
How's the bike riding do you like the 26-in rear wheel how fast does it go ? What voltage ?
Plus I like that style of trailer.