How do you attach big sprocket to back hub?

[Beagle123]

I'm trying to make a rear wheel for my latest scooter, and I don't understand how to make it.

I want to make a wheel with a bigger sprocket on the right side, and a disc brake, or drum brake on the left.

Others have found ways of attaching sprockets like this:

<img src="http://www.rqriley.com/imagespln/elchop-1.jpg">

It looks like he bolted it on in some way.

The problem is that I can buy a hub that accepts a disc brake like this:

http://cgi.ebay.com/DT-Swiss-Onyx-Disc-Rear-Hub-NEW_W0QQitemZ330127930399QQihZ014QQcategoryZ36143QQrdZ1QQcmdZViewItem

But they always seem to come with a cassette type adapter for the sprocket on the right side.

Can I replace the right side of the hub?

Also, I beleive that my motor sprocket is 25mm or 8mm or something. Its smaller than bicycle chain. I'd like to get a back sprocket that matches so I don't have to customize the sprocket on the motor.

Any ideas?

Another solution could be a drum brake hub. I've seen bmx hubs that are single gear with a drum brake. That would simplify my brake situation, but I would still have to attach the sprocket.

How are you guys tackling this problem?

 

[TylerDurden]

Hey Beagle,

Most of the crew are running hub motors...

The hub you linked is 85 bucks. I got a whole bike with front/rear disk brakes for $80 at toysRus.

If your frame doesn't have lugs for the calipers, it could be a pain to make em. They gotta be kinda precise.

Randy Draper uses kart sprockets on his bike. They can take 8mm chain I think. There are some hacks for sprockets on the net, if you poke around.

 

[Beagle123]

Thanks Tyler:

I already bought a Mongoose Mountain bike from WalMart for $160. I'm going to use the front suspension forks and wheel with disc brakes from it. Its nice to have the whole assembly.

I think you're right about the back brakes. It would be easier to use drum brakes.

I blew it when I missed this auction:

http://cgi.ebay.com/BMX-bicycle-rims-drum-brake-hub-wheels-old-school-MX_W0QQitemZ280115817098QQihZ018QQcategoryZ64644QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

But perhaps I can find something similar.

However attaching a sprocket still remains as the major problem. I welded a sprocket on my last project. That's still a possibility, but centering can be an issue.

safe managed to attach disc brakes to his bike. I beleive they may have some adjustment in them so they don't have to be positioned perfectly.

This is also available:

http://losangeles.craigslist.org/sfv/bik/345893354.html

 

[TylerDurden]

If you get a threaded hub, check out stuff like this:

http://www.electricscooterparts.com/sprockets.html

 

[Beagle123]

NICE!!! That looks great. I'll look for a hub to match.

 

[Beagle123]

I think we're on the verge of a solution. Look at the hub in the right column near the bottom of this page:

http://www.wildernessenergy.com/bargain_corner.html

I bet that would fit the gizmo you showed. And it fits disc brakes. The only thing better would be drum brakes I guess.

I'll pick up this search later.

Thanks for your help tyler.

 

[Mathurin]

On disk vs drum brakes, my experience has been that disks tend to fade away when they over heat, so you clamp hard and nothing much happens. Drums tend to fade in when they overheat, so you barely touch the lever and the wheel locks up. Your mileage may vary.

 

[safe]

On disk vs drum brakes, my experience has been that disks tend to fade away when they over heat, so you clamp hard and nothing much happens. Drums tend to fade in when they overheat, so you barely touch the lever and the wheel locks up. Your mileage may vary.

I've been overheating my disc brakes on occasion and I've got the ultra hard brake pad material which makes that even more likely. (though it slows the wear down a lot over the stock pads) One trick I've found is to use some sandpaper every once and a while to rough up the disc rotors and clear away any areas that have become ultra smooth. This also eliminates the squeeking that the brakes tend to make.

 

[Beagle123]

Hi Safe:

You're just the guy I wanted to hear from. How did you build your back wheel? I noticed that you managed to weld your frame in such a way that disc brakes could be used on the front and back. How difficult is it to attach disc barkes?

Please look at the above thread. Can I use Tyler's solution with the hub I found to make a back wheel?

Thanks.

I love your bike. You've inspired me to try to build a frame myself. The wheels are my first component.

 

[safe]

If you own a welder it's a job that takes a couple of hours of cutting, grinding, drilling and finally welding. Without a welder, a grinder and a drill I don't know how you would do it. A drill only costs $40 and the grinder only costs $40, but the welder can be in the hundreds of dollars. Also, if you use oxy-acetylene gas you need to refill them and I've already spent over $100 just on gas refills.

Plus you will need to learn how to weld. It's something that takes practice and I learned the skill when I was in my 20's... so it's second nature for me now. You have to remember that in 1982 I was actually welding my "gravity bike" style road racer frames and building fiberglass fairings for them. So if you really want to get into the "frame builder" hobby you need to realize that it does take effort to make happen. Expect to spend the first few days with the welder just practicing on some scrap metal before you even attempt the real thing. Test your welds by tearing them apart and looking to see how deeply you attached the metal. Novice welders tend to simply melt the steel welding rod on top of the metal you want to weld and it has no strength. To get a really strong weld you need lots of heat and you need to weld really fast. The faster and hotter the weld the better...