Torque bar

[Mel in HI]

I have read several places of people installing a torque bar...  Is this just something you are making yourself to prevent the hub from turning or??

[myelectricbike]

They are available commercially and I think there is a link posted on this site, Try the key phrase torque arm.

[Dalecv]

You can check out this post on how I made my own torque bar;

http://goldenmotor.com/SMF/index.php?topic=127.0

[mustangman]

  Humm , I think I see a marketing opportunity here....

[myelectricbike]

Yeah, I was thinking the same thing. I had a guy here stamp a rectangular hole in a sheet of 5mm cold rolled steel not long ago with a press he kept in his garage... wonder how many he could do in an hour in 10mm chromoly of which the local scrap yard has plenty.

[mustangman]

 My brother in law is making me a set out of 3/16 mild steel or med, hard plate. The hole will be totally enclosed and not open like a open end wrench, giving the piece even more stregnth despite the thin metal, If it works out, I will approach a local metal shop to mass produce them. The hole diminsions are 10mm on the flats x 14 mm on the other sides. 

[ahend]

Here are a couple screen dumps of the torque arms I designed and produced for my front suspension fork, which is made from aluminum. At the bottom of the arm I welded a couple small tubes to house a 10-32 bolt. The bolt will keep the arm from spreading and ensure a good bite onto the hub axle. The arms are made of 3/16” O1 tool steel. I made one for each side.
I abandoned the strap idea shown here in lieu of an aluminum anchor block which saddles the fork arm. I could not produce the strap with the desired result.

Andy

[mustangman]

Aah, aluminum forks with aluminum dropout!! Yikes, I hope you check your wheel daily and have great healthcare insurance in case the wheel come loose.

[Dave]

My brother in law is making me a set out of 3/16 mild steel or med, hard plate. The hole will be totally enclosed and not open like a open end wrench, giving the piece even more stregnth despite the thin metal, If it works out, I will approach a local metal shop to mass produce them. The hole diminsions are 10mm on the flats x 14 mm on the other sides. 

Mass producing them is a great idea, but keep in mind the wide variety of fork designs out there. I've got a number of bikes in my garage right now (eight I think) and no two of them have forks that could use the same torque bar without some modification. Some adjustability/hackability is almost necessary in that sort of thing.

EDIT: It just occurred to me... rather than mass producing a torque arm that may or may not work with a particular fork, how about mass producing a heavy duty fork specifically designed for use with an electric hub motor instead?  Most every bike has either a 1" or 1 1/8" head tube that the fork mounts in, so universality is less of an issue with a fork. I'm thinking of a fork with shock absorbers and a steel dropout with something that bolts onto the bottom of the dropout to fully enclose the axle and help keep the dropout from spreading. Hmmm....

[myelectricbike]

Also while you are at it how about 3/8" or 1/2" thickness for the torque arm hangers to be certain that even after a major torque event that you can still ride without need of repair, including even a little hammering, bending or resetting?

[ahend]

In my case, if I went any thicker, I would not have enough threads to positively secure the nut. In the case of the nut on the cable exit side, it would be tightened using only half of the axle threads due to the design of the cable exit passage. This would certainly fail.
O-1 is a very tough steel, and since I'm doubling up, and actively secureing the torque arm spread to the axle flats, I anticipate no problems. So far all is good, but I do check them each commute, not only visually, but with a wrench.

Andy   

[myelectricbike]

That's a good idea, which somehow slipped past me until it was too late.

[Dave]

In my case, if I went any thicker, I would not have enough threads to positively secure the nut. In the case of the nut on the cable exit side, it would be tightened using only half of the axle threads due to the design of the cable exit passage. This would certainly fail.
O-1 is a very tough steel, and since I'm doubling up, and actively secureing the torque arm spread to the axle flats, I anticipate no problems. So far all is good, but I do check them each commute, not only visually, but with a wrench.

Andy   

The fork ends I'm thinking of are similar to what's used on a lot of motorcycles; two bolts go through the bottom of it, firmly gripping the axle between it and the end of the fork. Here's a photo of something along those lines. If it's designed properly, there wouldn't be a need for a nut on the axle to bind it in place; the fork end could be as wide as the available flats on the axle, thus almost impossible to blow open.

Now youse guys gots me thinkin'...

[myelectricbike]

  Humm.. Better change those fuses up there is the old skull ...think I smell something burning ...just kidding. 

The scenario I'm looking into is whether or not getting rid of the press fit axle and flats and replacing them with a keyed hollow hub might not be the better way to go. Why? They can also be used to build wheelchairs and recumbents, but in the case of an axle extention on each side can use a closed and keyed hanger hole instead of an open slot that can be easily pried apart. I'm debating whether the key should be sacrificial like a prop key on an outboard motor and how many keyways there should be.

[mustangman]

  ....answer one keyway, whether or not sacrificial. Briggs and stratton has used this method for years on protecting the engine on rotary lawnmowers when they hit a rock or other solid objects. (otherwise their would be alot of broken crankshafts)