yantra yatra
100 W
could you please explain about the pulling in different directions? Do you need to set them up differently for this?
Leaf / leafmotor / leafbike high efficiency 1500w motor
- Thread starter neptronix
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Chalo
100 TW
When the motor is propelling forward, the axle is trying to rotate backwards. If you only have forward propulsion, it bumps into the the limit of the torque arm flats and stays there. But when you use regen braking, the axle tries to rotate forward. Alternating drive and regen rocks the axle back and forth, which tends to unscrew the axle nuts until a catastrophic failure occurs.
The remedy being suggested is to slew one torque arm forward to brace against the axle turning backward, and the other torque arm backward to brace against the axle turning forward, before screwing them down firmly. In this way you can minimize (but not completely eliminate) the range of motion through which reversing torque backs off the axle nuts.
lnanek
10 kW
You could buy a motor with an integrated torque arm if you really want to do regen. Grin has one.
The Toecutter
100 kW
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The more the range of motion increases, the faster the rate of change in the rate of motion increases. Quality torquearms and correct installation are everything.
Given the mileage I have ridden and the lack of unwanted drama on this subject for my use case since the first and only failure, I suspect that tightening down torquearms and axle nuts will be so seldom on my builds that it will only need to happen as a result of a tire/tube change or wheel/motor service as has been my experience thus far. I can literally go 10,000+ miles without issue on this, with regen being the vast majority of my braking. When I remove the axle nuts to periodically check, everything appears flush and solid without any noticeable gap or movement.
That is the result of using high-quality, precision-machined torquearms and/or clamping torqueplates on both sides and checking to assure everything is seated correctly during installation, coupled with programming low max regen current/torque into the controller setting. Anything less robust than this, and I wouldn't trust regen at ALL for my use case thanks to my first and only failure where I lost an axle nut. I was about to kill off any idea of using regen at all after that. I'm glad I tried it again, because I love it.
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ZeroEm
10 MW
The problem is most torque arms have some play. Some people have tried to shim the slack out. The issues arise from how much power you have or use. If you use low enough power you don't need torque arms. Same with regen if lightly used the axel does not twist the opposite way. As Chalo pointed out it does not always work. I'm at my limits if I used more power would need to go to clamping dropouts.
Note that no matter how good a torque arm is, motor axle flats aren’t always machined to spec, so a poor axle can contribute to looseness. As mentioned, shimming may be an option. I used a piece of a razor blade to jam between the axle flat and torque arm for a super tight fit. It’s a hassle to remove, but better than the problems any movement would create.
Whenever I have a loose TA, I fire-up the MIG and add a few brief tacks to the axle flat(s), then hand-file it to achieve a tight TA fit. When I specify 'brief',... that's exactly what I mean. If you're concerned about excessive heat disrupting the axle temper or perhaps a motor seal, then you have no clue what a 'tack' is.
ti is worth noting that in this case as in others, it's not the fall that kills you, it's the sudden stop at the end.
So because of the accelerated motion, and the amount of motion, the impact at the end of motion is greater, and the resulting surface and structure modifications
of the meeting materials is greater.Given the popularity of those leaf motors, how comes there is still no decent inbuilt torque arm option ? Flattened axles should really be obsolete by now, and I have a couple of cheapo chinese DD motors that actually came with useable torque arm mounts so I don't think it's a cost problem.
ITs' cheap, and it "works" (in that people still buy them anyway).
Engineering a correct and easy to install "universal" solution isn't easy; it took Grin quite a while to come up with what they use now for GMAC and GAA. Even if the many other motor companies out there just copied Grin's (or heinzmann's) it'd take a while to get them to start making *working* versions of them (meaning, correct copies, not just wrong general-idea-copies like usually happens). They have to get both materials *and* design correct, on the motor and the arm and the mounting bits for the frame end.
Ebike.ca has high standards and the added difficulty of adapting existing models. If you're a manufacturer, you can easily change your molds / machining setup for simpler torque arm implementation.
For an instance, the first DD hub I had was an early go swissdrive. The TA was a simple 50-60mm long piece of Steel cut with a square hole matching an equally cut slot on the axle. Still worked way better than all flattened axles I've seen, even in Regen mode. Arguably go swissdrive was a super expensive motor, but their TA implementation was cheap and simple.
So I guess you're right when stating that "people still buy them anyway".
yantra yatra
100 W
Would this dropout / swingarm work with the Leaf 1.5kw? Using regen with a couple of torque arms. It looks like carbon fibre above the dropout on the swingarm but seller says it's not. Would be using at 3-5kw. Are dual suspension frames generally seen as an ok choice for the Leaf? It's a BMC Trailfox 1. I think the dropout width is 135mm.
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What does it sound like when you gently tap it with a wrench, along the length of the stays, vs the dropout, vs the rest of the frame? If the sound changes from the metallic sound of the dropouts to a duller sound on the stays, it's probably not a metal tube.
yantra yatra
100 W
What is the widest tyre you can run on the standard rim with the 26" 1500w Leaf? On the page it says for 2.0 - 2.5", but having run 2.4in Schwalbe Super Moto X recently I feel like it would be good to run something a little bit bigger. Any suggestions for a good tyre? Super Moto X is a kind of hybrid tyre. some gravel and tarmac crossover capability which suits me well.
hillslayer@
1 kW
I just put a 2,6 on an 25 mm wide rim looks like about the max.
yantra yatra
100 W
What did you use?
I had very bad experience with super moto X. Those tires tend to loose very quickly all grip in rainy days, and you can forget about gravel. Get a tire with a deeper profile. Also, about rim vs tire width: you can put almost any clincher tire on any rim, though if the tire is too wide, it will require a lot more pressure and quickly become wobbly when pressure is down. So i'd always recommend to go the widest rim you can get. The tire itself is limited by your chainstay spacing and your chainline. With derailleurs a 2.5-2.6" tire might already rub against the chain if you have a standart 68mm BB.
^-- exactly on the money
If the leaf rim today is anything like what i got in 2014, i ran 2.2 inches and thought that was too wide for the rims, but it worked because i had a full suspension bike and pumping the tire's PSI way up helped alleviate the physics problem.
If the leaf rim today is anything like what i got in 2014, i ran 2.2 inches and thought that was too wide for the rims, but it worked because i had a full suspension bike and pumping the tire's PSI way up helped alleviate the physics problem.
OkinawaJapan
1 W
- Joined
- Jun 17, 2012
- Messages
- 57
This thread is hands down my favorite one on the forum so far in my research this week.
It's been a goldmine of information by all of you. Thank you.
I almost ordered a leaf bike 1500w DD hub motor, but after reading all the comments on torque arm safety I decided to just bite the bullet and order the Grin Max45 rear slow wind hub after all. Costs 2x the price but decided to prioritize the safety and silence aspects of it over saving a few bucks. Plus it's a bit lighter.
But... I think I may still order up a Leaf 1500w DD here next month for my second build and try it out. Perhaps even throw two V7 Grin torque arms on it as my backup bike as I think I'm going to like the regen aspects so much I won't want to live without it on my other ebikes.
Anyway, glad to be here and finally posting after joining so long ago. lol.
I think I may start a build thread or two for my two new ebikes so I have somewhere to share my details.
Again, thanks for all the golden knowledge shared here. It's already making a big quality difference in my purchases.
It's been a goldmine of information by all of you. Thank you.
I almost ordered a leaf bike 1500w DD hub motor, but after reading all the comments on torque arm safety I decided to just bite the bullet and order the Grin Max45 rear slow wind hub after all. Costs 2x the price but decided to prioritize the safety and silence aspects of it over saving a few bucks. Plus it's a bit lighter.
But... I think I may still order up a Leaf 1500w DD here next month for my second build and try it out. Perhaps even throw two V7 Grin torque arms on it as my backup bike as I think I'm going to like the regen aspects so much I won't want to live without it on my other ebikes.
Anyway, glad to be here and finally posting after joining so long ago. lol.
I think I may start a build thread or two for my two new ebikes so I have somewhere to share my details.
Again, thanks for all the golden knowledge shared here. It's already making a big quality difference in my purchases.
The Toecutter
100 kW
- Joined
- Feb 8, 2015
- Messages
- 1,529
If you want to do a performance-oriented build, that still remains light and efficient enough to pedal on a disabled motor or empty battery, the 3T version of this motor is perfect. It will handle 10kW peak and 250A peak phase current on a regular basis with ferrofluid and hubsink added. My trike accelerates like a fast car and even without a body currently on it I can run it at 45 mph until the battery runs dead without the motor overheating and even do 70 mph for a few minutes at a time(takes 10kW and the motor gets hot), with just one of these motors. You definitely need torquearms on both sides.
I'm convinced a single one of these motors is enough to power a 200 lb aerodynamic microcar and sustain highway speeds without overheating(~2-2.5 kW continuous depending on voltage/cooling). It's that good.
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yantra yatra
100 W
After reading a thread recently I’m thinking it’s probably good to put a 4t of this motor on a bike with suspension fork at least or dual suspension. Was going to put it on a bike with rigid fork and 2.4in tires, but hitting a pothole or rock at speed might not be safe
Yeah you absolutely want full suspension after around 30mph, aka 48kmh
The Toecutter
100 kW
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Full suspension is a must. Even with it, hitting a pothole at 32 mph on the mountainbike gave me the death wobbles, but fortunately I was able to correct that. Without full suspension, I don't think I'd have fared so well.
raylo32
100 kW
All I have had is mid-drives so this may be a dumb comment, but can you not use a little blue or maybe even green threadlock to help prevent the axle nuts from loosening?