Is this torque arm configuration ok?

General Discussion about electric bicycles.
Post Reply
ebike11
10 kW
10 kW
Posts: 937
Joined: Nov 16, 2013 8:01 pm
Location: Korea

Is this torque arm configuration ok?

Post by ebike11 » Dec 09, 2017 3:03 am

Hi guys
I was wondering if this is ok for torque arm attachment? I got some generic M16 axle sized torque arms and this seems to be the only way to mount the main piece that slides over the axles.
I was thinking on mounting them on the inside of the frame but its too tight of a fit and too close to the freewheel.
Also, is it ok to have the torque arms bascially be as large washers for the axle nuts? I seen some photos of another person who had his motor nut tightened against the bike frame then the torque arm on the outside of the nut and then another nut on the remaining few available threads on the outside.
At the moment i dont have extra nuts to do that.
Thanks for your input!

Image

Image

Image

Image

User avatar
dogman dan
100 GW
100 GW
Posts: 34453
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Is this torque arm configuration ok?

Post by dogman dan » Dec 09, 2017 8:10 am

Looks ok to me.

Omit the washer if you need to, to get the nut fully on good threads.

Better if possible, to install the axle part of the TA different, and then bolt right to the frame, drilling a new hole in the dropout plate. This is not always possible, but if it is, go for that. This photo shows how it did work on one of my bikes. If you can't do that, nothing wrong with your current install, provided the hose clamp is not too shitty. There are some out there that are just china cheap and weak. I look for old ones from decades ago at garage sales, that hold better.
Flat space around the rear dropouts.jpg
Flat space around the rear dropouts.jpg (145.82 KiB) Viewed 519 times

ebike11
10 kW
10 kW
Posts: 937
Joined: Nov 16, 2013 8:01 pm
Location: Korea

Re: Is this torque arm configuration ok?

Post by ebike11 » Dec 09, 2017 11:08 am

dogman dan wrote:
Dec 09, 2017 8:10 am
Looks ok to me.

Omit the washer if you need to, to get the nut fully on good threads.

Better if possible, to install the axle part of the TA different, and then bolt right to the frame, drilling a new hole in the dropout plate. This is not always possible, but if it is, go for that. This photo shows how it did work on one of my bikes. If you can't do that, nothing wrong with your current install, provided the hose clamp is not too shitty. There are some out there that are just china cheap and weak. I look for old ones from decades ago at garage sales, that hold better.

Flat space around the rear dropouts.jpg
Thx a lot
No i am not using any washers on the outside. The torque arms are basically thick washers and the nuts had plenty of threads.
However on the inside, I still use the torque washers that came on the motor itself. They dont grab onto any metal. They are basically washers on the inside of the frame but they have a metal groove sticking out that goes in the dropout opening. They might catch on the dropout in the worst case scenario but barely.

ebike11
10 kW
10 kW
Posts: 937
Joined: Nov 16, 2013 8:01 pm
Location: Korea

Re: Is this torque arm configuration ok?

Post by ebike11 » Dec 09, 2017 10:58 pm

dogman dan wrote:
Dec 09, 2017 8:10 am
Looks ok to me.

Omit the washer if you need to, to get the nut fully on good threads.

Better if possible, to install the axle part of the TA different, and then bolt right to the frame, drilling a new hole in the dropout plate. This is not always possible, but if it is, go for that. This photo shows how it did work on one of my bikes. If you can't do that, nothing wrong with your current install, provided the hose clamp is not too shitty. There are some out there that are just china cheap and weak. I look for old ones from decades ago at garage sales, that hold better.

Flat space around the rear dropouts.jpg
I dont have space in my frame to bolt to to directly

User avatar
MadRhino
10 GW
10 GW
Posts: 4916
Joined: Sep 03, 2010 5:28 pm
Location: Montreal QC Canada

Re: Is this torque arm configuration ok?

Post by MadRhino » Dec 10, 2017 1:09 am

It will do for a low power ebike, but don’t go feeding high power before making proper torque plates or strong dropouts.
Make it fool-proof, and I will make a better fool.
Current bikes
Street: https://s20.postimg.org/ewrvugywt/Session_04_2015.jpg
Dirt: https://s20.postimg.org/lbqwr55ml/IMG_0157.jpg

ebike11
10 kW
10 kW
Posts: 937
Joined: Nov 16, 2013 8:01 pm
Location: Korea

Re: Is this torque arm configuration ok?

Post by ebike11 » Dec 14, 2017 8:04 am

MadRhino wrote:
Dec 10, 2017 1:09 am
It will do for a low power ebike, but don’t go feeding high power before making proper torque plates or strong dropouts.
Even if there is a torque arm on each side?

User avatar
dogman dan
100 GW
100 GW
Posts: 34453
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Is this torque arm configuration ok?

Post by dogman dan » Dec 14, 2017 9:22 am

Depends on what you call high power. For 3000w on up, I recommend something like this. This is what I had for racing.
Pinch dropout, on Race bike..jpg
Pinch dropout, on Race bike..jpg (90.59 KiB) Viewed 325 times
Or in any case, for motorcycle like power, you need to have something designed to hold more than 1 hp, usually a custom rig of some kind, torque plate, custom swing arm, or whatever. On a steel bike, it can be as simple as welding on material to make your dropout twice as thick. Quarter inch of steel can hold a lot. On my cargo bike that runs 2000w, I just welded on the cheap steel derailleur hanger, and added length to it. Holds 2000w just fine. A solid quarter inch of steel total, after the eighth of an inch hanger is welded on is plenty for that bike.



The clamping dropout in the pic above is welded to the frame on one side, but if you again, had tons of room on the dropout plate, then you can do a bolt on one.
mongoose pinch dropout.JPG
One way to make what you have hold more than 1500w or so, would be to set your bolt on the pivot of the two piece torque arm, then have it welded in that position. This will make your TA much stronger, and more resistant to having it able to pivot, and the clamp slide down the stay its clamped to.

Yer fine though, for 1000w or so, provided your hose clamps are not shitty, and the bolt on the TA pivot is not loose.

Better, would be a set of grins technologies universal rear TA's. What you have is originally designed for front forks, but does fit the rear of many bikes ok enough for 1000w.

Or custom make a torque plate that can bolt to your frame directly, or at least have no pivot. This is easier to do than you might think. Set the pivot screw on your ta, then trace it on paper. Cut steel to match the paper. Now you have a TA with no pivot to loosen, and its custom fit to that bike.

User avatar
wturber
1 kW
1 kW
Posts: 387
Joined: Aug 23, 2017 8:52 pm
Location: Fountain Hills,AZ
Contact:

Re: Is this torque arm configuration ok?

Post by wturber » Dec 14, 2017 1:14 pm

dogman dan wrote:
Dec 14, 2017 9:22 am


Or custom make a torque plate that can bolt to your frame directly, or at least have no pivot. This is easier to do than you might think. Set the pivot screw on your ta, then trace it on paper. Cut steel to match the paper. Now you have a TA with no pivot to loosen, and its custom fit to that bike.
I think he's suggesting something like this. Also, there's a great thread with tons of torque arm pictures here:
https://endless-sphere.com/forums/viewt ... =2&t=26444
P1380755_TA_GearSide.jpg
P1380755_TA_GearSide.jpg (168.1 KiB) Viewed 311 times
P1380748_TA_unmounted.jpg
P1380748_TA_unmounted.jpg (67.11 KiB) Viewed 311 times
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
7 x 36v 4.3ah 10s 2P battery packs - Wangdd22 1500W 30A DC Boost Converter delivers 54v and about 1175 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
https://endless-sphere.com/forums/viewt ... =2&t=90369

ebike11
10 kW
10 kW
Posts: 937
Joined: Nov 16, 2013 8:01 pm
Location: Korea

Re: Is this torque arm configuration ok?

Post by ebike11 » Dec 14, 2017 7:06 pm

dogman dan wrote:
Dec 14, 2017 9:22 am
Depends on what you call high power. For 3000w on up, I recommend something like this. This is what I had for racing.Pinch dropout, on Race bike..jpg

Or in any case, for motorcycle like power, you need to have something designed to hold more than 1 hp, usually a custom rig of some kind, torque plate, custom swing arm, or whatever. On a steel bike, it can be as simple as welding on material to make your dropout twice as thick. Quarter inch of steel can hold a lot. On my cargo bike that runs 2000w, I just welded on the cheap steel derailleur hanger, and added length to it. Holds 2000w just fine. A solid quarter inch of steel total, after the eighth of an inch hanger is welded on is plenty for that bike.



The clamping dropout in the pic above is welded to the frame on one side, but if you again, had tons of room on the dropout plate, then you can do a bolt on one. mongoose pinch dropout.JPG

One way to make what you have hold more than 1500w or so, would be to set your bolt on the pivot of the two piece torque arm, then have it welded in that position. This will make your TA much stronger, and more resistant to having it able to pivot, and the clamp slide down the stay its clamped to.

Yer fine though, for 1000w or so, provided your hose clamps are not shitty, and the bolt on the TA pivot is not loose.

Better, would be a set of grins technologies universal rear TA's. What you have is originally designed for front forks, but does fit the rear of many bikes ok enough for 1000w.

Or custom make a torque plate that can bolt to your frame directly, or at least have no pivot. This is easier to do than you might think. Set the pivot screw on your ta, then trace it on paper. Cut steel to match the paper. Now you have a TA with no pivot to loosen, and its custom fit to that bike.
Actually im using 3000w MXUS hub motor..top speed for me is about 70kph but average speed 40 to 50kph

markz
10 GW
10 GW
Posts: 4977
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: Is this torque arm configuration ok?

Post by markz » Dec 14, 2017 11:21 pm

Was hoping someone would post up the 'ole crescent wrench torque arm.

Any easy DIY torque arm would be to buy some steel from Harbour Freight or similar store, and grind out the perfect notch, and bolt it on. You wouldnt necessarily need a tap and dye set, but you would need holes to mount it.

User avatar
dogman dan
100 GW
100 GW
Posts: 34453
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: Is this torque arm configuration ok?

Post by dogman dan » Dec 15, 2017 8:02 am

Get those TA's down to a welder, and set them permanent at that pivot angle then.
TA welded to fix position.jpg
TA welded to fix position.jpg (94.96 KiB) Viewed 247 times
If your clamp can slide on the stay, it will with 3000w pushing on it. It may not happen, but it surely will if for some reason a nut gets a tiny bit loose. Once it starts to go, no amount of tightening the pivot bolt will do the trick.

That is a nice custom bolt on plate, but some bikes that is just not possible. What I meant was make a one piece copy of the TA you have now, without the pivot bolt. With no ability to pivot, then the clamp cannot slide down the stay.

Either way, IMO, a TA with a pivot bolt to adjust to fit the bike is not enough for 3000w on up.

Fwiw, I spent a whole winter developing a TA similar to Grins, but it would use two bolts on the pivot. The user would have to drill the second hole themselves, making a custom fit that could not pivot at the connection. If you are really interested, here is one of the versions I came up with.
Universal rear torque arm.JPG
Same basic shape as in the pic, but instead of the oval hole, the user would drill thier own hole someplace on the area where the oval hole is on this picture.
On hardtail..JPG
In this picture, its installed on a FS bike, with a pivoting swing arm that wont allow the TA to go to the stay that has a pivot in it.

In the last pic, this is the final version of the rear torque arm I came up with. Multiple holes to choose from on the axle piece, and the same dogbone shape on the next piece, allowing drilling at the angles that fit best, and locking it in with two bolts that cannot pivot. Feel free to copy, or even produce for sale.
Attachments
On a FS bike, with pivot..JPG
PA220038.JPG

Post Reply