Torque Arms.

[Ajax]

The two e-bikes i own never featured Torque arms. Maybe the dropouts were stronger.

I think I need a pair now, but I can only find one design. Is there a UK source for decent torque arms?

I found this site showing a range of torque arm designs. I can only find their V1.

Torque Arms - Grin Products - Product Info

For every force there is an equal and opposite force, and for every torque there is an equal and opposite torque. Sadly with import hub motors this opposing torque is often born entirely by bicycle dropouts that are not up to the task, allowing the motor axle to spin out. Grin has pioneered the...

ebikes.ca

 

[saneagle]

There are every type on Ebay. I'd avoid the cheap ones that look look like they're stamped out, and make sure you get the right size for your axle.

Torque Arm for sale | eBay

Find great deals on eBay for Torque Arm. Shop with confidence.

www.ebay.co.uk

 

[Bikes4two]

Why do you think you need torque arms?

Your two bikes without - were they conversions or proprietary? Have you had dropout problems?

 

[Nealh]

Don't buy any that use a jubilee hose clip to clamp the main secondary arm.
If one is capable then one can make their own small one piece TA's out of a bit of 2.5 - 3 mm steel.

Steel forks/drop outs are safe usually with 250w motors without TA's, the exception may be the heavier duty BPM or Heinzman hubs.

 

[Ajax]

Why do you think you need torque arms?

Your two bikes without - were they conversions or proprietary? Have you had dropout problems?

Both bikes were proprietary, but then the motor on one froze one winter and had to be replaced with whatever i could afford.

Later i had to replace the bike frame and rebuild the bike when the bottom bracket failed and could not be repaired.

The other day after lengthy repairs, the rear hub jumped out of the frame, breaking the derailleur hook.

so yeah, time for Torque arms.

All i can find on Amazon are those mrk 1 versions with the Jubilee clips.
If you know of a uk source for something better i would welcome it.

 

[thelarkbox]

Grin will ship to the UK but North americans are honest to a fault on customs declarations, so ordering a few with the intention of ebay sharing the spares could backfire with vat charges etc. Any Canadian family/palls to act as a go-between ? You could ask em to declare nominal $1 steel machine parts ala Chinese sellers, but dont hold yer breath

 

[portals]

Don't buy these cheap sh1te ones, they are very soft metal and I almost managed to rip a hose clip with two of these on a 1500W hub....

I have designed my own in Tinkercad and when I work out what I'm doing with rear hub will be getting local metal guy to CNC my 3D design.

Hose clip was....hosed.....

Grin ones are very expensive, local metal guy might be better option.





Non-drive side TA





Drive side TA





This is my design.

 

[thelarkbox]

Looking at the grin drawings i was thinking if copying and sending off to laser/waterjet cutting services would be viable?

 

[portals]

Dear Grin, you don't need a failed mosfet to tear a hose clamp in half...just a 1500W motor...

 

[portals]

My design is similar to their 2003 _V5 version except mine is for my bike and not adjustable, that version wasn't available when I first looked in to this.

You could try copying it but whilst Grin provide quite detailed pdf manuals they don't publish the dimenions of parts so you'd need to measure up.

Using a 3D printer is great for this, I can print prototypes in minutes for pennies and tweak until it's precise, this is great for me as I was always crap at accurately measuring stuff, even measure twice cut once never really panned out, measuring bike stuff again I always sem to be a little out...when you can print it you can sort dodgy measuring

 

[Benjahmin]

I've used these with no problems.

https://www.amazon.co.uk/hammer-engineering-Ebike-Adjustable-Angle-Torque/dp/B09NRVN892/ref=asc_df_B09NRVN892?mcid=b5679981cf263320bd8120cafec5f8b9&hvocijid=4350943417513200329-B09NRVN892-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=4350943417513200329&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9222618&hvtargid=pla-2281435176698&psc=1&gad_source=1

I think they do other sizes if you search.

 

[Nealh]

I find 5mm is often too thick to allow decent purchase for a axle nut to tighten.
The last thick TA I bought many years ago was one of John's @Cyclezee, I ended up grinding it down to 3mm .
Hence now if I need one I make my own up with abit of old steel of 2.5mm , the critical part is making sure the axle fitting is a perfect fit, once one has the axle fit and fixing bolt hole aligned then one can shape the TA.

 

[portals]

I've used these with no problems.

https://www.amazon.co.uk/hammer-engineering-Ebike-Adjustable-Angle-Torque/dp/B09NRVN892/ref=asc_df_B09NRVN892?mcid=b5679981cf263320bd8120cafec5f8b9&hvocijid=4350943417513200329-B09NRVN892-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=4350943417513200329&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9222618&hvtargid=pla-2281435176698&psc=1&gad_source=1

I think they do other sizes if you search.

I looked at these yrs ago, didn't bite in end as they only connect to one eyelet whch then becomes the weak spot, I also thought 5mm was too thick.

 

[eas2lv]

Grin will ship to the UK but North americans are honest to a fault on customs declarations, so ordering a few with the intention of ebay sharing the spares could backfire with vat charges etc. Any Canadian family/palls to act as a go-between ? You could ask em to declare nominal $1 steel machine parts ala Chinese sellers, but dont hold yer breath

Even if "we" were ready to do that, GRIN's shipping charge within Canada is not cheap -- CAD 17 for the CAD 27 torque arm. So, you'll need to find not just a dishonest Canadian, but someone who can pick up locally in Vancouver. Tall order
Amazon.com will ship free within US, but prices are higher than from GRIN direct.

 

[Ajax]

I've used these with no problems.

https://www.amazon.co.uk/hammer-engineering-Ebike-Adjustable-Angle-Torque/dp/B09NRVN892/ref=asc_df_B09NRVN892?mcid=b5679981cf263320bd8120cafec5f8b9&hvocijid=4350943417513200329-B09NRVN892-&hvexpln=74&tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=4350943417513200329&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9222618&hvtargid=pla-2281435176698&psc=1&gad_source=1

I think they do other sizes if you search.

Thank you for the recommendation i've just ordered it. The disc brake side is also the cable side from my hub. This should be interesting. I like the fact the sprocket comes out allowing you to get that ideal fit to the axel.

Edit: I just realized the link above is for a 12mm x 10mm axle, whereas mine is a 14mm x 10mm axle. I had to cancel and reorder. Watch out, folks.

 

[Ajax]

Don't buy these cheap sh1te ones, they are very soft metal and I almost managed to rip a hose clip with two of these on a 1500W hub....

I have designed my own in Tinkercad and when I work out what I'm doing with rear hub will be getting local metal guy to CNC my 3D design.

Hose clip was....hosed.....

Grin ones are very expensive, local metal guy might be better option.

View attachment 62103



Non-drive side TA

View attachment 62101



Drive side TA

View attachment 62102



This is my design.

View attachment 62104

The jubilee clip is certainly the weakest point of this design. All that potential load on that thin sheet metal, not to mention its screw mechanism where the quality can vary. Those things also rust when left out. It seems wise to have a back up. If you are using this design then grease it and maybe add a second jubilee clip.

 

[Benjahmin]

Thank you for the recommendation i've just ordered it. The disc brake side is also the cable side from my hub. This should be interesting. I like the fact the sprocket comes out allowing you to get that ideal fit to the axel.

Edit: I just realized the link above is for a 12mm x 10mm axle, whereas mine is a 14mm x 10mm axle. I had to cancel and reorder. Watch out, folks.

Go to the Hammer bike site. I'm fairly sure they do a 14mm one.

In fact, here it is:

Product Page

www.hammer-ebikes.com

 

[matthewslack]

The jubilee clip is certainly the weakest point of this design. All that potential load on that thin sheet metal, not to mention its screw mechanism where the quality can vary. Those things also rust when left out. It seems wise to have a back up. If you are using this design then grease it and maybe add a second jubilee clip.

Not that simple.

The force seen by the hose clamp/jubilee clip is affected by the tightness of the bolt clamping the two pieces of the torque arm together. Any looseness there translates into sideways sliding forces on the clip, and rapid failure.

Wear or any space for movement in the axle hole does the same, and also tends to loosen the clamp bolt.

The hardest working part of a torque arm is the bit that sees the full torque at a tiny radius, meaning very high surface loading, which is the corners of the axle hole where the edges of the axle flats bear.

The thicker and tougher the material the better at that point, but limited by axle space for wheel nut.

Checking for tightness and wear needs to be a routine task, every ride with a powerful motor.

 

[matthewslack]

My design is similar to their 2003 _V5 version except mine is for my bike and not adjustable, that version wasn't available when I first looked in to this.

You could try copying it but whilst Grin provide quite detailed pdf manuals they don't publish the dimenions of parts so you'd need to measure up.

Using a 3D printer is great for this, I can print prototypes in minutes for pennies and tweak until it's precise, this is great for me as I was always crap at accurately measuring stuff, even measure twice cut once never really panned out, measuring bike stuff again I always sem to be a little out...when you can print it you can sort dodgy measuring


View attachment 62108

Transferring that to metal using hand tools is not so hard. Use the 3D print as a stencil and spray paint the shape onto metal. The round holes are easy, start small to get an accurate centre and work the size up in stages. The axle holes need files and a vice to finish, but it does not take long.