The importance of good quality torque plates

[Racer_X]

From my point of view it almost looks like it was that axle that gave in more to the failure? What does the forum think?

[Diamondback]

I think the amped bikes TQ arms are designed for 14mm axles. Not 12mm.
If that's the case, it might explain the failure mode..

I'm running two of their TQ arms. One on each side.
I'm also running a maximum of 1000w (peak) with closer to 750W constant.

Jason

[NeilP]

The axle went first as I first assumed and the start of the thread, caused by the thinness of the arm,
It was tight when fitted, I had to get a round file and make the slot fractionally longer to fit it over, same goes for slot width, not much, but it needed a couple of strokes with a fine file on inside of flat part of slot to get it to fit

It is simply a soft axle combined with a thin plate and although relatively low power 1.5 to 2kW it was enough for the plate to chew the soft axle material

[kfong]

Torque arms needs to be thicker to spread out the load.

[Alan B]

Not much damage to axle - only three threads flattened.

The dropout didn't help much - maybe five threads even less flattened.

These 12mm axles don't have much to grip on. (Why did Crystalyte use them on the new Hx35 series???)

One torque arm, on the side that loosens the nut when the axle spins. No NordLock washers that tighten in either direction.

Just not enough to do the job, apparently.

Thanks for the info. I have a new Crystalyte HT3525 with 12mm axles. Planning to use a pair of the ebikes.ca torque arms on it. Plus NordLocks. Wonder if that is sufficient.

[LI-ghtcycle]

Ouch! Glad you didn't crash as a result, and thank you for again pointing out how important it is to have proper size and fit of torque arms.

I have hand fit torque plates of my own using a file and dremel making it just loose enough to fit with out tapping it on with a hammer, and STILL had trouble with a 12 MM axle on my NuVinci, and this was before I had a motor installed, leg power alone.

It's easy to understand once you have experienced it, but hard to fathom how much torque is really being put on such a small area on those axle flats until you have it happen first hand!

I would also recommend some form of hardening of the steel after you have made the plate, especially with a 12 MM axle. 14 MM axles are not anywhere near as prone to failure from what I have seen so far in my limited experience, however I had to harden and temper the torque plate on the smaller axle side (left side) of the NuVinci, with minimal power (leg power).

Now even though I peak at around 2500W of load, 1100 constant, I have not had any trouble since I hardened the plate.

Fortunately for me, the NuVinci has very hard and tough axle material, and it actually dug into the plate making a portion of the plate "threaded" before partially flattening a part of the threads.

Nothing wrong with any of the common torque arms sold with E-Bike kits that I have seen, just that there are limits to them, and anything with near 3x the rated wattage is going to cause most any commercial torque arm to fail save Doctor Bass's and other people's heavy duty custom built ones.

The difficult part if you don't have a proper machine shop like me, is working the steel if it's already hardened, much easier to build with it mild, and then go back and harden it later.

I have had really good luck so far with torque plates built from a cheap tow hitch receiver from a pawn shop I got for like $10, and it's probably not just mild either, it's a step somewhere in between, and after about 3 attempts, I got it to harden significantly, and 546 miles later, it's still doing fine.

[dogman]

Definitely the 12 mm axle flats are too short to do much good. After reading Justins fork failure thread, one of the most interesting things to me was how much difference it made if the nut was simply tight.

My conclusion was that a relatively tight nut gave quite a bit of the torque resistance required for a typical sub 1000w power hubmotor. To me, it explained why the standard was, and still is for some vendors, to just supply a lame torque washer. In essence, you could get away with it if you simply had a reasonably tight nut. The amped torque arm is quite adequate for the use it was designed for. 36v 20 amp controllers.

But you don't get away with much when you run 80v 40 amps.

[Racer_X]

Thanks for the heads up on the Crystalyte axle. Had no idea it was 12mm.

Crystalyte use them on the new Hx35 series

[Hillhater]

I think it odd that you posted this before you know how it failed. ?
It would have taken less time to run that axle nut off and pull the torque plate, than the time taken to snap the pictures. !
Why not find out how it failed and then post, rather than all this speculation ! ??

[Doctorbass]

Torque plate MUST not only be THICK but the material they are made with MUST BE STRONG to deformation!!!

That's why the ultimate torque arm i'm offering are THICK ( 10mm) and STRONG... QT100 pure High Quality Canadian Steel Heat Treated and Quenched and Tempered

I bust the max power the all my X5 can do and never noticed any scratch or sing of deformation on them.

QT100
Alloy
High Strength


Alternate Common Terms:

T1 -100
Weldox
Scandia100
Welten 80C
CHT 100
A514
Algoma 100 (Link to Algoma Steel)
RQT 701
CSA G40.21-92-100QT
ASTM A514 Grade S


Tensile 110 ksi
(760 MPa)
Yield 100,000 psi
( 700 MPa)
BHN 235/293
C 0.20
Mn 1.50
P 0.03
S 0.015
Si 0.45
Mo 0.40
B 0.0005/0.005


The hub motor axel will break BEFORE the torque plate begin to have deformation

For the price you pay for a single "torque" arm.. The one i offer come in pair so you have two for the same price for a total strengh of like 10X

BTW.. the new batch is arrived... fresh from the laser cut

[LI-ghtcycle]

100% agreed there Doc! Mild steel is worthless with out some heat treating if your going to get some real serious power going, and yours are a bargain! Too bad I need both 12MM and 14MM sizes.

Hmm maybe you can shrink one down for me, after all, you have everything in that amazing shop of yours right? So a shrink ray to make some into 12MM would be no problem right?

[Doctorbass]

100% agreed there Doc! Mild steel is worthless with out some heat treating if your going to get some real serious power going, and yours are a bargain! Too bad I need both 12MM and 14MM sizes.

Hmm maybe you can shrink one down for me, after all, you have everything in that amazing shop of yours right? So a shrink ray to make some into 12MM would be no problem right?

Please give me the dimension of the axel cross sectional area and i'll see what i can do

[biohazardman]

Yep, too thin..I thought so before I used it...that is why I never used it before..it just looked too thin and weedy for anything.

Seems like I am repeating myself here..ot trying to sound rude..because it is not meant that way..but read all my previous posts...a scrap frame dragged out of the scarp trailer..and that is where it is going back too, it is bent any way, it was only brought out along with that hub motor as a test bed for the controller

I actually never pulled off from a standing start with it, I always pushed off with the feet first, got coasting before tuning the 'throttle'
Even before I started I was not happy with the little torque arm.

I also left plenty of slack in the phase wires..to allow any wind up ..as seen int he first pictures. The axle did not as much spin..as chugg its way around in small steps ..

Both frame and torque served a purpose..for a moment at least..now they are destined for the scrap

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Those are the torque arms I use on my BMC V2 @ 66V and 30A, that's a good amount of wattage, without problems so they are plenty strong. I do have mine on the other side of the frame though and possibly a bit more secure too. Yes, the single arm also supports most of my kick stand as well.



I have used other types none of them being all that thick of metal but all held up just fine. Axles were all 14mm not 12mm though so things fit a bit tighter. I noticed on some motors that the axles are not machined all that well and some are even undersized. The nuts and washers they send with them are not even usable as they wobble when being put on and don't sit flat when tightened. So there are many things to go wrong and destroy stuff. Sorry about yer failure but expect when you get it werqed out it will be better than original. Good luck
Oh, by the way pretty darn good photos for a phone.

[Hillhater]

... Mild steel is worthless with out some heat treating....

The only "heat treatment" you can do to "mild steel" is case hardening, which only gives a surface hardening of about 0.2mm deep...like a thin hard crust on a soggy pie ! ...not very useful for this situation.
You need a high carbon steel to get effective full hardening from heat treatment after machining.

Its time some of these motor manufacturers made a motor with a big bearing ( 2") ? to allow a more effective torque reaction bracket to be attached direct to the stator, and eliminate all the space issues for phase wires etc.
( just like Hal did ! )

[zombiess]

I use the ampedbikes torque arms on both my builds pushing over 7kw and the axle doesn't move at all. Have over about 800 miles between them, had the motors out and no signs of the axle getting cut by the torque arm. Failure was caused due to lack of a good flat spot on that axle. I'm also using 9C motor which seem to have a bit higher quality than the xlytes from what I've seen posted on here.

[ZOMGVTEK]

I was running 6-7kW for months with no torque arms/plates. I know of 3 other people running 6kW into a stock $100 bike without issue.

I'm not saying its a bad idea, but I just don't see why its such a big deal on a few kW setup. Install it properly, make sure the bolts are tight, and avoid front motors like the plague.

Regen, however, is an entirely different story.

[LI-ghtcycle]

100% agreed there Doc! Mild steel is worthless with out some heat treating if your going to get some real serious power going, and yours are a bargain! Too bad I need both 12MM and 14MM sizes.

Hmm maybe you can shrink one down for me, after all, you have everything in that amazing shop of yours right? So a shrink ray to make some into 12MM would be no problem right?

Please give me the dimension of the axel cross sectional area and i'll see what i can do

Will do doc! I believe the dimensions will be the same for a bafang axle, I will make some measurements and PM them to ya first thing tomorrow.

[NeilP]

I think it odd that you posted this before you know how it failed. ?
It would have taken less time to run that axle nut off and pull the torque plate, than the time taken to snap the pictures. !
Why not find out how it failed and then post, rather than all this speculation ! ??

Because it was late..I only had the crappy camera on the iPhone, and knowing how crap the pictures on it are...I just wanted to take proper pictures of it with a better camera. If i had started mucking around with it there and then..I just know more damage would have resulted.

Not that it matters now of course

[icecube57]

It looks like your axles have piss poom achining. The flats are bigger on one side than the other so the torque arm didnt have a proper fit. Ive used two amped bikes torque arms on a 5303 and a 9C running at very high voltages and high amperages on a tidal force frame and never saw this. The last time I saw something like this is when I had a 9C 1606 with bad axle flats and they did the same exact thing in the torque arm.

People are right about the 14mm torque arm doesnt work properly on a 12mm axle.

[TonyReynolds]

It appears that the thinner the torque arm material, the more it acts like a knife-edge, concentrating the force along what becomes an edge. I'm not sure that the hardness of the steel matters as much as the thickness, which presents more surface area to the axel. I think that's the key. Hardness, helps, but surface area is what does the trick. A fatter torque arm will have less tendency to "cut" through the axel, given the forces generated.

[NeilP]

Exactly, that is why I never used this after I received it for my 5304...I stuck in in the spares bin and made a pair of my own out of thicker material. Axle length was the only thing stopping me go any thicker

[dogman]

Pinch dropouts for the win. But a close second is those ones from the man, DR BASS! I need to snag one someday, because one of my bikes has a trashed derailur hanger, and I'm too lazy to cut one off another steel frame and weld it on.

Love that design Doc!

[icecube57]

But still why are we dissing this torque plate when it was install on a motor with fairly round axle flats and its 12mm vs the 14mm which the torque arm was designed for. Looking at the spin out damage on the torque arm shows there wasnt much contact area. It properly fits a GM a NC and x5 motors. Two of these Amped bike torque arms bolted in the torque arm slot of the TF Frame in tandem with the aluminium rear drop outs was sufficent of holding the X5303 at 88v and 125A producing 260nm or 191ftlbs of torque. I admit one is SKETCHY but i take two in between washers for the win.

[MadRhino]

...Axle length was the only thing stopping me go any thicker

That is a real problem, with many recent DH bikes having 150mm dropout width.
I switched from adding torque plates, to building replacement steel dropouts that are inserted deep into the swingarm tubing. Since they are not adding to the width from the start, I can make them much thicker. This makes for a neat, very strong setup, adding a pinch bolt can make the axle seating very safe for hard dirt riding.

[LI-ghtcycle]

But still why are we dissing this torque plate when it was install on a motor with fairly round axle flats and its 12mm vs the 14mm which the torque arm was designed for. Looking at the spin out damage on the torque arm shows there wasnt much contact area. It properly fits a GM a NC and x5 motors. Two of these Amped bike torque arms bolted in the torque arm slot of the TF Frame in tandem with the aluminium rear drop outs was sufficent of holding the X5303 at 88v and 125A producing 260nm or 191ftlbs of torque. I admit one is SKETCHY but i take two in between washers for the win.

That is the real key, if you use something and it fails, and you don't recognize that it wasn't designed to do what you were trying, it's kind of like a guy who builds a 500 HP & 700 F/Lb torque muscle car, doesn't beef up his drive-line or rear end and then talks about how (insert car manufacturer here) builds crap when he twists off his drive line, axles or destroys his transmission!