Dual torque arms
Posted by jjjameszzz@reddit | ebikes | View on Reddit | 61 comments
I put on two torque arms with the aluminum frame out of an abundance of caution. Do you think it's too much or just about right?
Posted by jjjameszzz@reddit | ebikes | View on Reddit | 61 comments
I put on two torque arms with the aluminum frame out of an abundance of caution. Do you think it's too much or just about right?
According_Bat2315@reddit
There the wrong way round ?
jjjameszzz@reddit (OP)
Nope. They are correct.
ScrewMeNoScrewYou@reddit
I'm curious as to why you have a derailer still when you've got no gear cassette?
brandcapet@reddit
I ride a single-speed rear-hub with a derailleur, it's mainly just to tension the chain evenly, but it also makes it easier to move/remove the chain when you have to disconnect the rear wheen/motor assembly from everything in order to change a flat or do other maintenance.
NumerousAddendum1617@reddit
Bonsoir je suis en train de finaliser le montage de mon vélo avec un moteur 3000 w 72 V et la roue libre single speed que j'ai commandé ne se visse pas à fond apparemment il me faut une roue libre au standard ISO / Anglais Et je galère dans mes recherches auriez-vous un lien style Aliexpress ?
jjjameszzz@reddit (OP)
Yes exactly. It makes taking off the rear wheel much easier
natermer@reddit
How do you tension a single speed chain without a track end?
Silly-Swimmer1706@reddit
Using chain tensioner.
jjjameszzz@reddit (OP)
I have a three-speed freewheel on there. It's on the lowest gear
Gullerback@reddit
aint that the truth. I have just a simple 1 speed freewheel but taking off the tires so much less of a headache
jjjameszzz@reddit (OP)
I took the shifter off because I never have to change it to a higher gear. I just leave it in that gear all the time. I used the screws to make sure it was constantly on the same gear
Mysterious_Bass6202@reddit
Yep, same here!
jjjameszzz@reddit (OP)
I agree
jjjameszzz@reddit (OP)
NumerousAddendum1617@reddit
Bonsoir, J'ai commandé une roue libre single speed pour monter sur mon moteur 3000 watts, et quand je l'ai reçu je n'arrive pas à le visser à fond, apparemment il me faut une roue libre au standard ISO / Anglais Et je galère dans mes recherches pourriez-vous me donner un lien 🙏 ?
MammothResponsible22@reddit
I have two on mine. Cant be over cautious ever! Axle spin sucks! I learned the hard way on my first bike and had to replace the rear swing arm from the dropouts getting chewed up. Rewiring a harness wasnt fun at all neither! Anyways, yours looks good! Ride safe!
pp___sucker@reddit
owners a cheap skate
EL_Chapo_Cuzzin@reddit
At what watts would you recommend a torque arm? I have a 750w peak, probably not enough.
AlternativeLoose8730@reddit
i wonder if these would help my bike, i have a full suspension mid drive ebike and i get torque flex in the rear swing arm.
tehsilentwarrior@reddit
It you are getting it in a different way. Those would do nothing as the torque is in the middle not the rear. You are getting it because the chain is getting high tension at the top pulling it forward and twisting
AlternativeLoose8730@reddit
any way to remedy that?
natermer@reddit
That can only be solved by having a better swing arm.
jjjameszzz@reddit (OP)
I don't think that would work with a mid drive motor. Torque arms only work with hub motors as far as I know but I could be wrong.
trixqo@reddit
You are correct the torque arm is to prevent the hub from spinning and damaging the dropouts the more torque and Amps the higher the likelihood of spin out.
skark_burmer@reddit
Each with dual hose clamps! The redundancy is redundant. :p
jjjameszzz@reddit (OP)
These are the hose clamps that come with the grin torque arms. They're actually quite strong.
RadroverUpgrade@reddit
Weird thing happened last week; my front axle nuts started
loosening on every ride. I have a front direct drive w/regen
that puts a lot of torque on the dropouts in both directions.
I found that after two years, the hose clamps on both Grin
torque arms had loosed up just a wee bit. After re-tightening,
the problem went away.
jjjameszzz@reddit (OP)
You can tell that they are pretty robust hose clamps when you are installing them. And I'm sure after 2 years they would become a little bit loose
RadroverUpgrade@reddit
I wasn't finding fault with Grin; their products are awesome.
Just wanted to give you a heads up on periodically checking
the tightness of the clamps. They are the weak link in the
gadget and work great as long as they are tight.
chuyskywalker@reddit
Mine started to rotate out of position after about 5 minutes.
https://endless-sphere.com/sphere/threads/fargrin-time-to-push-some-amps.127512/page-3#post-1865271
But, I don't supose you're going to be pushing 150 phase amps, so you'll probably be fine ;D
firekeeper23@reddit
All Torque
And trousers.
jjjameszzz@reddit (OP)
Not sure what that means...
firekeeper23@reddit
Im.sorry.
All talk and no trousers is a British saying meaning its all words and no action... whereas these brackets look simple but will work really well.... somits the opposite of all talk no trousers... all torque and trousers.
Sorry. Very obscure reference there.
jjjameszzz@reddit (OP)
Ok I'm in Canada so had no idea. Thx for clarifying.
firekeeper23@reddit
No probs. Best of luck with everything. And a wave from England.
Pristine_Goat9163@reddit
Minimum of 3 torque arms.
implicate@reddit
I don't exactly know what these are, but they look cool.
natermer@reddit
One is enough.
DarkMorph18@reddit
Is this necessary?
jjjameszzz@reddit (OP)
I don't know. That's why I put the question out there.
mister_k1@reddit
depend on how much watts you're outputting but i think its a good practice, one question tho, why not use a tensioner for the chain?
jjjameszzz@reddit (OP)
I have a derailleur on there. It acts as a tensioner
Formal_Tumbleweed132@reddit
I don’t ride w/o 2 of them anything over 3000 watt thatmotor has the potential yank that rim out in a heart beat (personal ecperience). It just makes me feel safer
Gojira_Wins@reddit
It's pretty much not going to do anything besides offer peace of mind. Aluminum wont be strong enough to stop the motor or other forces from bending the (likely) steel frame.
jjjameszzz@reddit (OP)
Oh really. So you think eventually it will break on me? Guess I'll have to start searching for a new frame
Mysterious_Bass6202@reddit
The weak part is not the arm, nor the frame, nor mounting on frame. It is the slot that grips the axle. Its tighness, the hardness of the steel and the thickness (contact surface) is what matters. I put 2 arms sandwitched on the solid axle side only, my opposed axle end is hollow for the wires. Also the tension of the axle nut is critical. I don't like the idea of tightening the hollow side a lot, so just the solid side properly torqued is my receipe.
MD_Reptile@reddit
Nah this dudes wrong, those are heavy duty grin torque arms, they'll provide actual support. Two is overkill honestly.
Gojira_Wins@reddit
Aluminum is a soft metal. If the frame is steel, aluminum torque bars will do nothing to stop it as steel is significantly harder.
If the frame is aluminum, the torque bars are aluminum and the motor bends the frame, the torque bars will only help so much. There is nothing incorrect about what I said.
MD_Reptile@reddit
The arms aren't aluminum, they are steel. Thick chunky steel in fact!
Gojira_Wins@reddit
I didn't vote you down, I was busy replying to OP.
Do you have a source for the arms?
MD_Reptile@reddit
The grin website:
https://ebikes.ca/product-info/grin-products/torque-arms.html
Gojira_Wins@reddit
Yeah, it seems like it. By the time I saw your comment, it was at -1. I usually dont see the value in downvoting someone unless it's pretty much negligent.
From what I see from your link, it is 17.5 stainless, but it might be a typo as it looks like 17.4 is more common. Either way, 1/4 17.4 would be good for this application but not long term or worse, in the case of an accident.
So, maybe I should use the term "insurance" instead of overkill for OP. It'll hold up to torsion, but a crash would bend them. It's a steel close to 304, and not being super thick (1/2 or more) would mean new torque arms after a nasty accident.
Hopefully, nothing like that happens.
jjjameszzz@reddit (OP)
They are most definitely thick hardened steel
jjjameszzz@reddit (OP)
Okay thank you. I thought it might be Overkill but I build bikes frequently so I can use The other torque arm on a different project. I want to make a tandem bike for me and the wife to ride around. I was thinking of putting this motor on the tandem bike
MD_Reptile@reddit
Haha that'd be cool. Good luck!
jjjameszzz@reddit (OP)
Thank you. It's very difficult to find a tandem bike with disc brakes on them, but I will keep searching
Gojira_Wins@reddit
I would only recommend looking for a new frame if this one breaks. The aluminum torque bars won't help in the higher end of cases, such as putting down 3,000W or more. That amount of torque will twist the frame because of how small it is.
For now, this is pretty much overkill since the motor likely isn't capable of generating that much power. You'll instead need to worry about possibly catching on plants and curbs.
400footceiling@reddit
Please take the reflectors out of the spokes.
jjjameszzz@reddit (OP)
I'm just in the process of finishing this bike. I haven't gotten around to that part yet.
MaxTrixLe@reddit
No such thing as too much, I run dual Grin V6 on my steel frame.
jjjameszzz@reddit (OP)
It's quite a peppy motor. I was just paranoid about the aluminum. Hopefully the torque arms will add plenty of strength. I run 72 volts, 14 amp hour battery. I wish I had more amp hours though, but that's much more cash.