Golden Motor + Disc Brakes

[Johnbear]

This was an interesting job. It started off as a cruise on the bikes. A friend and I stopped by Renaissance bicycle - ebikes.ca and got some thread on disk rotors. The plan was to try to get his new Shimano XTR hydraulic disc calipers to work with the golden motor. The golden motor only has one threaded cover. We robbed the other one from the backup golden motor.

Had to take the rotor off one adapter, go to home depot, find longer bolts and bolt the rotor to the two adapters.


We had measured the distance from the motor hub to the center of the disk and to the center of the disc brake caliper.

The fit was great!View attachment 1

This took about 4 hours. But in the end it worked!

 

[Gonzo]

Wow- great job. I was actually looking for ways to do that myself, including welding a bunch of washers to the hub. But your way looks so much neater. Now I just need to get that dam%^ed second threaded cover- nobody sells them. Do you guys happen to know when I could get a scrap rear Golden Motor with threaded hub cover? Or, better- the hub cover by itself?

 

[Johnbear]

I was just about to post looking for a second motor, if anyone has a burned golden motor, there are two buyer here for your covers. We had to sacrifice a cover from a functioning motor to make this work!

 

[Gonzo]

Lol- look what kindness brings about. Now you got a competitor for a cover =) O well, you can have the first one, I'll have the second.

Is that an 8" brake disc, by the way? My bike is a Giant Stiletto with 8" disc brake- and that's the only way to stop it. It's heavy, has huge tires and no way to mount V-brakes...

Are you over-volting your Golden Motor? I heard it runs fine on 48V- just need to replace some wiring with Teflon 16 gauge.

 

[Johnbear]

It is a 6 inch rotor. I'll let you know If I find a source for spare covers!

 

[Johnbear]

It is run by 36v lifepo4.

 

[SimonMTL]

Couldn't you just screw the disk brake directly into the cover, without taking it off nor opening the hub?

What speed are you getting with this setup on flat no wind?

 

[SimonMTL]

Wow- great job. I was actually looking for ways to do that myself, including welding a bunch of washers to the hub.

Actually, that sounds like a great plan! Do you think the welding would be strong enough? And, would the heat from the welding damage anything in there??

 

[Johnbear]

That is actually the 2nd motor that I robbed the cover from. There is only one threaded cover, so I needed the second to screw the disk to. It is around 32-34km per hr flat no wind. Torquey motor!

 

[SimonMTL]

That is actually the 2nd motor that I robbed the cover from. There is only one threaded cover, so I needed the second to screw the disk to. It is around 32-34km per hr flat no wind. Torquey motor!

What happens with the included Golden Motor cantilever brakes that halt the engine, when you only have disk brakes on your bike? I thought you needed to use those to take away power to the hub-motor when you are braking??

 

[Link]

That is actually the 2nd motor that I robbed the cover from. There is only one threaded cover, so I needed the second to screw the disk to. It is around 32-34km per hr flat no wind. Torquey motor!

What happens with the included Golden Motor cantilever brakes that halt the engine, when you only have disk brakes on your bike? I thought you needed to use those to take away power to the hub-motor when you are braking??

I was kinda wondering, too. Unless they sell hydraulic brake interrupts...?

Or do you not use any at all? I don't .

 

[Johnbear]

They are not in use, if the bike tries to run away at least there are good brakes!

 

[SimonMTL]

They are not in use, if the bike tries to run away at least there are good brakes!

John, what do you think if I just measured properly, identified where the holes should go on the cover of the hub, and just drilled small holes (without taking the hub cover off) and screwed in the disk rotor, with a good measure of glue that bonds aluminium between the hub cover and the spacer (making sure I sand off the paint from the cover to get better adhesion)?? There is nothing in there that I could damage by just drilling blindingly, although not going too deep, just enough to get through the cover??

I think that could make it a bit easier for those of us with disc brakes...

 

[Johnbear]

It is really easy to remove the cover, I would suggest doing this just in case. You would need some strong adhesive to stop a heavy e-bike , post some pictures! I am sure you can make it work.

 

[Link]

John, what do you think if I just measured properly, identified where the holes should go on the cover of the hub, and just drilled small holes (without taking the hub cover off) and screwed in the disk rotor, with a good measure of glue that bonds aluminium between the hub cover and the spacer (making sure I sand off the paint from the cover to get better adhesion)?? There is nothing in there that I could damage by just drilling blindingly, although not going too deep, just enough to get through the cover??

I think that could make it a bit easier for those of us with disc brakes...

I was just thinking the same thing. Only I was gonna weld nuts to the inside of the motor (assuming I had room) to keep it simple and clean-looking.

Ah, better wait until I get my Golden Motor from ebikes.ca to see what I could do. :wink:

 

[SimonMTL]

It is really easy to remove the cover, I would suggest doing this just in case. You would need some strong adhesive to stop a heavy e-bike , post some pictures! I am sure you can make it work.

Well, so far, I had to spread apart my rear dropouts to fit the hub-motor, and even with a high quality aluminium frame (Giant AC full suspension) I noticed later tonight that... it bent. My beautiful MTB has bent alu. Not good. Looks like I'll forget about using it as my donor bike, and I'll buy a cheapo steel bike before putting more damage to my expensive bike! ARGH!

Ah, the joys of building a first e-bike!

Found on eBay a 2008 PACIFIC Highlander (100$ shipped), and a MICARGI Polo (210$ shipped) - either one of them should do the trick. One with horizontal dropouts, the other with vertical. Any preferences or doesn't matter in the end? Still the need for torque arms on a steel frame?

 

[Link]

One with horizontal dropouts, the other with vertical. Any preferences or doesn't matter in the end? Still the need for torque arms on a steel frame?

Don't think there is. Mostly has to do with the way the rear of the frame was made?

You probably will be fine with no torque arms on a steel frame if it's a rear hub. Front might be iffy. I'd use them just for the peace of mind.

 

[Johnbear]

The Giant AC is a nice bike, It is a real bummer that it bent. What is the with of the axle on your golden motor? Is it 135? The one my friend is using is a snug fit on a Giant AT hardtail.

What kind of spacers were you planning to use to space the disc brake?

I prefer vertical dropouts - the motor sits right in snugly!

 

[Gonzo]

Simon, when you apply the brakes, the torque on the disc is just too great. I'd expect all your assembly of small screws and aluminum glue to fall off the first time you press the lever At least do yourself a favor, take the cover off and use large bolts which directly attach the adapter to the cover- and preferably without spacers! Spacers would work if you have a threaded cover, but here I'd expect them to considerably weaken the assembly.

Additionally, if you don't take the cover off and just drill from outside- expect metal filings to fall inside the hub. NOT GOOD! They can cause shorts, wear out parts, etc.

So I strongly suggest either welding or using the same method described in this thread- use an adapter and a threaded cover, or make a custom adapter and bolt it directly to the hub using strong bolts.