Search found 711 matches

by Buk___
Apr 19, 2018 3:49 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Anytime somebody starts bragging about how great they are, it's a red flag. I'm not "bragging", just stating what I know to be true. Should I back down and pretend I'm wrong when people denigrate what I've written -- and along the way, contradict established engineering practices, material science ...
by Buk___
Apr 19, 2018 3:29 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

In my case, neither controller responds to any form of braking control other than on/off. :( Unfortunately most controllers are like that, and only some (though a growing number) can do proportional braking, where there is some method for a degree of control over how much braking force is applied. ...
by Buk___
Apr 19, 2018 3:14 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Chalo wrote:
Apr 19, 2018 12:52 pm
I could get into more math and physics ...
Prove it! (ie. Put up, or shut up.)
by Buk___
Apr 19, 2018 7:20 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Chalo wrote:
Apr 19, 2018 1:19 am
Buk___ wrote:
Apr 18, 2018 9:24 pm
I don't need luck, I've got math & physics.
One day you'll learn how to use them, kid.
This, from you, Chalo. Really!

And "kid" :)
by Buk___
Apr 18, 2018 9:24 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Alan B wrote:
Apr 18, 2018 8:06 pm
Stooping to personal attacks? Wow. I expected better.
Since when is challenging your technical opinion, and the manner in which you deliver it, a "personal attack".
Alan B wrote:
Apr 18, 2018 8:06 pm
Good luck.
I don't need luck, I've got math & physics.
by Buk___
Apr 18, 2018 9:15 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Apologies for derailing the thread...it wasnt my intention. :( You didn't! If it helps, they are each the MXUS 45H, a 4503 and a 4504. {snip:details} Some math based on those details. Mass: 1/4 ton (225 kg). Speed: 20mph (32kph, 8.89m/s); Time: 3 seconds. Acceleration: 8.89 / 3 = 2.963 m/s² Distanc...
by Buk___
Apr 18, 2018 4:27 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

... Most everything you said in this post -- and you said a lot -- is wrong. But as always with you, you 'state' your opinion, but do not cite any references; show any math, formulae or laws -- no numbers at all; construct vector force or free body diagrams; not even a picture or two; nor even offe...
by Buk___
Apr 17, 2018 1:45 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

As long as the traction is not broken (Chalo's point), the torque is a function of the motor and the current. Not of the system weight. ... Max power on regen is at max speed, to get full battery voltage would require downhill that was sufficient to get to unloaded wheel speed. At normal speeds the...
by Buk___
Apr 17, 2018 12:24 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

If I am understanding it correctly, it ought to work for the typical ebike power levels, and probably even up to the power levels Im using on SB Cruiser, since its split between the two motors, though itd be pushing towards the upper end of the topical intent of these. Not even close. With 2 pairs ...
by Buk___
Apr 17, 2018 12:03 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

If I am understanding it correctly, it ought to work for the typical ebike power levels, and probably even up to the power levels Im using on SB Cruiser, since its split between the two motors, though itd be pushing towards the upper end of the topical intent of these. Not even close. With 2 pairs ...
by Buk___
Apr 16, 2018 6:36 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

If I am understanding it correctly, it ought to work for the typical ebike power levels, and probably even up to the power levels Im using on SB Cruiser, since its split between the two motors, though itd be pushing towards the upper end of the topical intent of these. Not even close. With 2 pairs ...
by Buk___
Apr 16, 2018 7:53 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

We have seen thick solid chrome moly steel dropouts with no relief slots spread by 12mm hubmotor recoil when they were slightly less than fully seated. I think this is a somewhat similar "force multiplier" to the slots in this proposed design. Once again, the difference is between trying to deaccel...
by Buk___
Apr 16, 2018 4:19 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

amberwolf wrote:
Apr 16, 2018 1:19 am
...
I guess I was mistaken. Strange though that I would quote it, and then misread it.

Even stranger that you would come along and make such a song & dance about such an off topic point so long after the fact.
by Buk___
Apr 16, 2018 12:29 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

There's not much point in arguing about it, only testing can prove anything. Build some and fail them with a torque wrench, as Justin has done so many times. What I'm sayin'. I don't have to prove the design is bunk; he can just try it out and see for himself. YOU can't prove the design is bunk; yo...
by Buk___
Apr 15, 2018 10:05 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Any torque arm that is C-shaped will have a strong tendency to spread apart. That is exactly what it is designed to do. Absorb the energy rather than fight it, thus preventing the axle flats from impacting the dropout faces. It's novel, but not that hard to understand. A full circle around the axle...
by Buk___
Apr 15, 2018 9:48 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

You can't just go putting notches and sharp corners on parts that are stressed in tension. When you do that, you're telling it exactly where to fail, and to do it quickly Chalo, you sound like you may have some legitimate concerns, could you throw together a quick and dirty drawing of what you cons...
by Buk___
Apr 15, 2018 8:55 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

The design I posted is such that the jaws are the same diameter as the axle nut flange -- based on those supplied with my motor -- so if the flanged nut fits inside any lawyer lips (my bike doesn't have them), so would the jaws. Many motor axle nuts dont have any flanges, or any kind of ribbing/etc...
by Buk___
Apr 15, 2018 8:17 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

In your last post you mentioned that the hardness of the materials that the Nord-Lock was in contact with [paraphrase] was critical, and went on to list those as "the torque arms and axle". Just to be clear (since Im always trying to learn much more about mechanical engineering types of stuff and s...
by Buk___
Apr 15, 2018 7:44 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

it's plain to anybody with mechanical engineering chops. Sorry pal, but you do not have any mechanical engineering chops. You're a spanner monkey with ideas above his station. When you start posting something more than your hyper-inflated opinion, of stuff you so obviously have little more than a p...
by Buk___
Apr 15, 2018 4:10 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

If you can't tell the functional difference between an entire loop of flat spring added as a feature, and a localized thin spot created by cutting a slit partway across a plate, I'm afraid I can't help you. Make one and test it to failure with a torque wrench. See for yourself what you can't seem t...
by Buk___
Apr 15, 2018 11:17 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

What I'm pointing out has nothing to do with materials properties but everything to do with your part shape. You can't put a narrow neck in the middle of a piece that's loaded in bending without causing stress to concentrate there. If you put a much thinner spot in the middle of a flat spring, it t...
by Buk___
Apr 15, 2018 6:08 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

999zip999 wrote:
Apr 14, 2018 11:49 pm
Go get a plate of Steel a 4in grinder with cutoff wheel. Make a template get some chalk or a soapstone and a vise. Weld on two nuts and drill one out.
Some context as to what this is meant to address would be useful?
by Buk___
Apr 15, 2018 5:37 am
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

In the thin axis, these springs are capable of being wound tight, and stretched flat and back again many millions of times. Each infinitesimal section of metal can be flexed though 20°. 30°, 90° or 180° without harm. Flat springs are thin throughout their lengths. Your TA is "thin" (not in absolute...
by Buk___
Apr 14, 2018 6:35 pm
Forum: E-Bike Technical
Topic: The ultimate torque arm (For <2kW and standard axles)?
Replies: 78
Views: 1020

Re: The ultimate torque arm (For <2kW and standard axles)?

Mostly it's about those things flexing across their thin axis, thus greatly attenuating stress levels for a given deflection. The opposite of what you're asking of your spring stock. Chalo, you tax me :) I know you are not a great lover of oval (and other shaped) pressure formed frame elements, but...