Is This Right?
- Thread starter EarlB
- Start date
LewTwo
1 MW
NOPE ... Mostly an aesthetics issue (i.e. does it look right to you).EarlB said:
LewTwo
1 MW
That is why they make both vanilla and chocolate (as well as a bunch of other flavors) of ice cream. Personally, given a choice, I would never have a defrailurer (and I do not like rocky-road either).getmo35 said:
EarlB said:
I'm going to say no, since in both videos they are using a piece of crap stamped steel torque arm that is so loose they won't do anything to keep the axle from rotating. Make sure to use two, since they can help keep the wheel from falling off after the bolts get loose.
PS. Assuming no regen, and if you use the crappy stamped steel arms on the front fork, then I would mount them in the back, with two clamps each. I would place the second clamp halfway down the curved longer arm. This will twist the arm portion the opposite direction as the axle wants to spin. Your motor axle is always going to try to spin in the opposite direction as your wheel, so by preloading the torque arm against the direction the axle wants to spin, you've removed the slack, and increasing how effective it is.
What's misleading about the Grin pics? They look accurate and configured correctly. I haven't seen many better pages on the subject.
I am new to this, and I am learning. So, I try to ignore your hostile negativity and look at the content of what you are saying. I have found better teachers in here. Grin torque arms are not in stock. If you had read my initial post in here, you would understand that I plan to set the torque arms up for MY trike, then have them welded solid before the final mounting. I have already figured out how to use 3 hose clamps on each one, IF I cannot use a u bolt. My aim is for NO movement allowed. I do not know much about ebikes, but I have 65 years of mechanical experience. I have a drill press, grinders, cut off wheels, and any tools I need. And I am two minutes away from a friend who welds and has many times more tools than I do. I am just trying to get a solid understanding of the dynamics involved.
My hub will have regeneration, so my front setup has to be solid and secure. I get it. I am looking at what others are doing. If I don't ask questions, how do I learn?
I clearly stated what was wrong with the grin pics. I am a novice. The front fork pics are facing left, and the rea fork is facing right. That was initially confusing for me. After studying the pics more I understood. An experienced person would see it clearly immediately. I know knew absolutely nothing about ebikes 2 weeks ago. I came here to learn. I have experience and education in many other areas of life that few in here have, and I would always try not to be arrogant about it.
I learn best from people without an arrogant attitude.
If I can get two torque arms on each fork, I will. Being aware of the danger, I will keep an axle nut wrench on my trike and check my nuts very closely to watch for a pattern of loosening. Pretty simply thing to do.
My hub will have regeneration, so my front setup has to be solid and secure. I get it. I am looking at what others are doing. If I don't ask questions, how do I learn?
I clearly stated what was wrong with the grin pics. I am a novice. The front fork pics are facing left, and the rea fork is facing right. That was initially confusing for me. After studying the pics more I understood. An experienced person would see it clearly immediately. I know knew absolutely nothing about ebikes 2 weeks ago. I came here to learn. I have experience and education in many other areas of life that few in here have, and I would always try not to be arrogant about it.
I learn best from people without an arrogant attitude.
If I can get two torque arms on each fork, I will. Being aware of the danger, I will keep an axle nut wrench on my trike and check my nuts very closely to watch for a pattern of loosening. Pretty simply thing to do.
E-HP said:
EarlB said:
No hostility meant. Pointing out the torque arms in both videos are pieces of crap. That's a fact. I added more information on how to make the most out of a piece of crap torque arm. Sorry your feelings were hurt. Please accept my apologies.
So the right approach if humility is truly valued
would be a thread asking "what's the best way to do front fork torque arms?"
Acknowledging that you're really looking for shortcut links to dozens of existing threads where the question's already been answered.
And responding with gratitude to people pointing out that video was made by a clueless idiot
and realizing YouTube is not a great primary source for such topics.
As opposed to Justin @Grin, where presentation / production / entertainment values may be sub par, but the information is worth 1000x more.
Getting it wrong on this particular issue could easily **kill you**, as opposed to putting the hub on the rear.
would be a thread asking "what's the best way to do front fork torque arms?"
Acknowledging that you're really looking for shortcut links to dozens of existing threads where the question's already been answered.
And responding with gratitude to people pointing out that video was made by a clueless idiot
and realizing YouTube is not a great primary source for such topics.
As opposed to Justin @Grin, where presentation / production / entertainment values may be sub par, but the information is worth 1000x more.
Getting it wrong on this particular issue could easily **kill you**, as opposed to putting the hub on the rear.
john61ct said:
Precisely why I added the one piece of information that hadn't been provided earlier in the thread, that could have a bearing on saving the OPs life in the end, that those arms are pieces of crap. I guess that information didn't mesh well with the OP, but I still think it's important to point out, in case any newbie's in the future, that do the searching for existing threads, will at least appreciate it.
I missed the part about having to read the OP's previous thread for context. Mind reading isn't as good nowadays.
LewTwo
1 MW
It is actually a function of the efficiency of the joints. For a single piece torque arm there is one joint where it attaches to the fork. For the more common case of two piece torque arms there are two joints: one where the arm attaches to the fork and another where the arms are joined.
If one was to do an engineering model in either case then those joints would be assumed to be static (i.e. fixed). In that case the direction of the torque makes absolutely no difference. In the case where the joints are not fixed (i.e. the fasteners are loose) then some argument might be made for pushing into or away from the fork body depending on whether the torque was generated by braking or motive power. However in the latter case it would also be argued that the installing the fasteners improperly was the greater danger.
One point is rarely mentioned is the quality of the fit between the hole in the torque arm and the axle. If that fit is not very good then all other questions are moot. All other things being equal, a thicker arm has more bearing area and the quality of that fit is directly proportional.
The same principles apply equally to both the front and rear of the bike.
If one was to do an engineering model in either case then those joints would be assumed to be static (i.e. fixed). In that case the direction of the torque makes absolutely no difference. In the case where the joints are not fixed (i.e. the fasteners are loose) then some argument might be made for pushing into or away from the fork body depending on whether the torque was generated by braking or motive power. However in the latter case it would also be argued that the installing the fasteners improperly was the greater danger.
One point is rarely mentioned is the quality of the fit between the hole in the torque arm and the axle. If that fit is not very good then all other questions are moot. All other things being equal, a thicker arm has more bearing area and the quality of that fit is directly proportional.
The same principles apply equally to both the front and rear of the bike.
LewTwo said:
Excellent point. I noticed how tight the tolerances are on the Grin torque arms with respect to the bolt holes. In my install, I eliminated the second part of the arm, and drilled and tapped a plate for the arm to bolt to, but was careful to choose quality bolts with the same tight tolerances, so no movement.
If those cheap torque arms had the joint a little further from the axis, at least even the loose joints might still provide some protection, but they aren't. Like the torque arms on a kids coaster brakes, if the arm is longer, there's a little more leeway for loose tolerances and the strength of the mounting point (that little pot metal strap that fixes it to the chain stay); use physics to substitute for poor tolerances and cheap materials.
LewTwo
1 MW
There are two ways of calculating the strength of a bolted connection. One is shear and the other is friction. These same civil engineering calculations are used in the of connections in steel bridges and building. In either case it still comes down to properly tightening the fastener(s).TDB said:
I will grant you that a single piece torque arm is a more desired design but so is avoiding the problem altogether with purpose designed attachment point. Unfortunately that is not practical in most instances.
LewTwo
1 MW
TDB said:
Right ... it has only lasted for six years ..... so far.
If it was to work then maybe it will last a century or more.
Similar threads
