The best torque arm

[Farfle]

I have have had constant problems with my torque arms, between regen and acceleration the motor will wiggle back and forth and eat the steel torque arms, no matter how tightly fitting I make them they still wear out. So my grandfather came up with a good idea, instead of applying force to squeeze the dropout with the axle nut, why not squeeze the axle's flat spots with another bolt? So I whipped up a pair, If anybody has any comments to improve this design I would be glad to hear them. Mounted on the bike you cant really see them, so heres a sketchup drawing of what it kinda looks like.

The axle is pinched by the 5/16 bolt, the 3/8 bolt looked a bit heavy. Plus if your axle nut somehow comes loose the bottom bolt will contain the axle and prevent the wheel from falling completely off.

 

[amberwolf]

Similar to the concept of the clamping dropouts John in CR (and others?) have done. Don't see why it wouldn't work, assuming the way they bolt to the existing frame/fork is secure enough, and in a place that won't twist off with force.

 

[lifepo4ever]

the only problem of this design you can only put on one side because of the deraileur will interfer with the 3/8 bolt and also is a 3/8 can bind the plate that mean your
plate is to thin i use 1/4 of steel plate for my custom torque arm . the plate goes inside the frame where is flat also this made some spacer for the gear

diferent picture from above look also this link : http://endless-sphere.com/forums/download/file.php?id=48795&mode=view

 

[dogman dan]

Make it thicker. I think John's are about 1/2" thick? 3/8 might work.

I built some clampers just the other day, but failed.

The bike is upside down in the pic btw. Steel frame to bolt to, but the angle iron is too thin and bends too easy. So I have to redo with either thicker angle, or just some square bar stock. I'll do better at positioning the bolts too.

Regular bolt on the other side, where the derailur gets in the way.

 

[John in CR]

I like your grandfather, he's a really smart guy. I don't know if it's important or not with steel, but I drilled a stress relieving hole for the end of the expansion cut so it won't develop a crack over time. For anyone making these with basic tools, I put 2 blades on a hacksaw to make the cut, because a single blade doesn't make a wide enough cut.

I agree with Dogman, thicker material. Mine may be overkill at >.5" on each dropout, but mine are the dropouts. Also, nice and thick makes them easy to fab because then you just drill a hole for the clamping bolt instead of a fancy structure to accept the bolt and nut. Of course my thick material clamping on the axle isn't nearly the overkill of 2 half inch bolts to hold the torque arm to the bike shown in the drawing.

Make a bunch of them, but leave off the holes to attach so people can drill their own in the proper location to fit their bike. There's a market for proper torque arms, and those currently sold are good for legal limit power and no regen just as you experienced.

John

 

[dogman dan]

Re reading, I see this is not a concept drawing, but a drawing of what you did.

Thick enough if it's working. How thick btw, I don't see it on the drawing. I do like the way you still get to use the axle bolt.

I assume it's a peice of pipe welded to a plate?

 

[Farfle]

OK, here is some pictures, the steel is 1/4" heat treated (dropped in used motor oil while red hot) and the pipe is not pipe, but a pair of nuts, one pair has been drilled thru, the other was threaded to the bolt and welded on. I ended up using 5/16 bolts because 3/8 was too big to weld to 1/4" steel, it just didn't line up. To attach them to the bike they are bolted to the bike by a pair of holes that were already in the dropouts, so I just ran a 1/2" drill thru them and put in a suitably beefy bolt.

 

[Farfle]

the only problem of this design you can only put on one side because of the deraileur will interfer with the 3/8 bolt

hmmm, I didn't think of that, but that would be a definite issue. I am running a ghetto single-speed right now so it didn't cross my mind.

EDIT: and WTH! looking at this picture, one of my disk brake bolts is gone

 

[lifepo4ever]

anyway my concept is the best of what i see for general use most of people is only have little power like you dogman if you run on ping battery you never gonna break my torque arm i ride with lipo at 100 volts for about 80 amps current for 7-8 month now you have to the same patern of the motor shaft but you to make it perfect so there no lose and still never have problem i use 4mm plate with 8kw of power

 

[lifepo4ever]

OK, here is some pictures, the steel is 1/4" heat treated (dropped in used motor oil while red hot) and the pipe is not pipe, but a pair of nuts, one pair has been drilled thru, the other was threaded to the bolt and welded on. I ended up using 5/16 bolts because 3/8 was too big to weld to 1/4" steel, it just didn't line up. To attach them to the bike they are bolted to the bike by a pair of holes that were already in the dropouts, so I just ran a 1/2" drill thru them and put in a suitably beefy bolt.

look nice but its complicated for nothing

 

[John in CR]

Those should work out well for you. I'd hammer on them as hard as possible for a couple of weeks before taking them off for painting. When you do check the axle as well as the torque arms for deformation, and if there is some then you need to go thicker. The reason I go so thick with mine isn't just to make the torque arm stronger but to give it more contact area on the axle, because some hubmotor axles are fairly soft steel. My first hubmotor spun the axle in the first 10ft of use. I had dual SS torque arms not well fitted to the axle flats, and the 3mm SS cut right into the axle allowing it to spin without deforming the SS. I want my axles to have to break or the stator spin on the axle before my dropouts or axle can deform and spin. Locktite on the clamping bolt threads is probably a good idea too.

 

[Farfle]

@ Lifepo4, yes these dropouts are very overkill for someone running a <3kw commuter. these are for the axle shearing stator spinning 10kw+ off road riders. I milled my old torque plates to .3780 and the axles are .3880 (10 thou interference fit) they had to be "convinced" to get on the axle and after a month of hard riding, they would be chewed up, I don't know how that shaft keeps getting away, I also run about 8kw, but mostly on DJ parks and trails.

 

[lifepo4ever]

i never say your system is not good its just to complicated and I can proof that my design work well after 8 month at 8kw with no problem and i can say i chase car every day
i don't think 10kw will eat my 1/4 steel plate because i made the test also at 9kw from my past controller , i just order the usb cable for my 18 fet controller and i will tune to 10 kw next week i am not scare at all to break it

don't forget to retight the bolt of your torque arm fews day of use because the metal need to sit until you tigth it at the maximum metal retract at hot temperature and at 10kw the shaft is hot , and i just see you don't have drill hole on the cover to cool down your x5 , for a 10kw rider i really thing you don't beat enougth you motor

 

[Drunkskunk]

I realy like the design. I may have to copy that for my next bike.

 

[Farfle]

well, I just took it apart to fix the phase wires and that thing STANK! but the windings were all still copper colored so I havnt cooked it yet, Is the lyen controller with 18 4110s able to dish out the abuse that will cook a 5304 at 23s?, cause I have been scared to tinker it up too far with the little programmer plug thing.

Heres some casualties of the lovely central Oregon basalt rock. , oddly enough the tube didnt pop

 

[Drunkskunk]

Oregon basalt rock? You anywhere around Smith Rock?

 

[Farfle]

kinda, I live in Bend Oregon. Smith rock is about a 30 mile drive from here.

 

[Drunkskunk]

Bend's a great town... I think. The parts I can remember... My brother lived there. I went to see him a few years back. he knew these strippers and.. The rest is all fuzzy. It was the best weekend I will never remember. But somewhere in there, we climbed Smith rock. When I go back, I want to ride the trails that seemed to go up through the north end of the park.

 

[lifepo4ever]

well, I just took it apart to fix the phase wires and that thing STANK! but the windings were all still copper colored so I havnt cooked it yet, Is the lyen controller with 18 4110s able to dish out the abuse that will cook a 5304 at 23s?, cause I have been scared to tinker it up too far with the little programmer plug thing.

Heres some casualties of the lovely central Oregon basalt rock. , oddly enough the tube didnt pop

this motor develop power so more heat just to prevent you can't use a barbecue sensor like i do but you have to put it inside your hub for best result so you can beat the motor and when he hit 110 degres you slack the trottle also hif you can drill big hole for cooling it it will also very good

I learn that from doctorbass , methods

 

[Gordo]

$

I like your grandfather, he's a really smart guy. I don't know if it's important or not with steel, but I drilled a stress relieving hole for the end of the expansion cut so it won't develop a crack over time. For anyone making these with basic tools, I put 2 blades on a hacksaw to make the cut, because a single blade doesn't make a wide enough cut.

I agree with Dogman, thicker material. Mine may be overkill at >.5" on each dropout, but mine are the dropouts. Also, nice and thick makes them easy to fab because then you just drill a hole for the clamping bolt instead of a fancy structure to accept the bolt and nut. Of course my thick material clamping on the axle isn't nearly the overkill of 2 half inch bolts to hold the torque arm to the bike shown in the drawing.

Make a bunch of them, but leave off the holes to attach so people can drill their own in the proper location to fit their bike. There's a market for proper torque arms, and those currently sold are good for legal limit power and no regen just as you experienced.

John

John;
I remember from school that it takes 200 pounds to shear a 3/16 soft iron nail holding a wooden brace, so I looked up a bolt shear strength table. IIRC one 1/4" bolt holding that torque arm to the drop out, will take 370 lbs to shear it. That is assuming the torque arm can overcome the friction between it and the frame.

Making your style of 1/2" thick dropout/torque arms and welding them in place of the standard drop out is the best solution I see. No bolts to interfere with the sprockets, brake rotor or anything else. Just as easy to weld your system as to weld the pinch nuts on the other system. I can have the finished shape water cut for @ $10 or plasma cut for $5. No hacksaw needed, cut the slot with the water and just drill and tap for the clamping bolt. I thank you for all the great ideas. As long as we are dealing with steel, it solves all the problems including width for a 10 stack cassette if you want. Just make the dropout larger, cut the frame back farther and weld whatever width you have axle length for. Mikie Like!

 

[Farfle]

$

I like your grandfather, he's a really smart guy. I don't know if it's important or not with steel, but I drilled a stress relieving hole for the end of the expansion cut so it won't develop a crack over time. For anyone making these with basic tools, I put 2 blades on a hacksaw to make the cut, because a single blade doesn't make a wide enough cut.

I agree with Dogman, thicker material. Mine may be overkill at >.5" on each dropout, but mine are the dropouts. Also, nice and thick makes them easy to fab because then you just drill a hole for the clamping bolt instead of a fancy structure to accept the bolt and nut. Of course my thick material clamping on the axle isn't nearly the overkill of 2 half inch bolts to hold the torque arm to the bike shown in the drawing.

Make a bunch of them, but leave off the holes to attach so people can drill their own in the proper location to fit their bike. There's a market for proper torque arms, and those currently sold are good for legal limit power and no regen just as you experienced.

John

John;
I remember from school that it takes 200 pounds to shear a 3/16 soft iron nail holding a wooden brace, so I looked up a bolt shear strength table. IIRC one 1/4" bolt holding that torque arm to the drop out, will take 370 lbs to shear it. That is assuming the torque arm can overcome the friction between it and the frame.

Making your style of 1/2" thick dropout/torque arms and welding them in place of the standard drop out is the best solution I see. No bolts to interfere with the sprockets, brake rotor or anything else. Just as easy to weld your system as to weld the pinch nuts on the other system. I can have the finished shape water cut for @ $10 or plasma cut for $5. No hacksaw needed, cut the slot with the water and just drill and tap for the clamping bolt. I thank you for all the great ideas. As long as we are dealing with steel, it solves all the problems including width for a 10 stack cassette if you want. Just make the dropout larger, cut the frame back farther and weld whatever width you have axle length for. Mikie Like!

The only problem of this setup, is that it only works on steel frames. but other than that it works very well.

 

[Gordo]

I have a 250 Miller with a 1lb Aluminum Spool gun so if I had an aluminum swingarm, I'd duplicate the shape of the steel dropout in Al, weld it on and bolt a steel pinch dropout on the outsides. Heck, I'd even try a 1/2" thick AL pinch dropout with steel insert in the pinch area. I have looked carefully at the MM steel dropouts on my 3.5KW scooter and they show no sign of spinning out. Me and the scoot weigh 500+lbs so I'm wondering how you damage a dropout on a bicycle without 10KW's at launch? I see my friend with 100V pretending he is on a unicycle most of the time and his axle is staying put. I guess "First comes the lesson and then comes the learning", hopefully!