How can I fit a single giant sprocket on a hub motor thread?

R

rg12

100 kW
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Jul 26, 2014
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1,596
Hey Dudes,

My hub motor has a single speed 16T freewheel that fits using a thread (not that one that you can pull (sorry for the lack of terminology)).

I want to have a single 60T that looks like this: http://cdn.shopify.com/s/files/1/0573/2837/products/OneUp-Components-42T-Sprocket-green-3d-front-966.jpg?v=1443551991
and have it as a freewheel.

Is it possible?
 
Can't see the site or pics, but if the center of the sprocket is large enough to fit over theh core of the freewheel, just drill bolt holes in it and bolt it to the teeth of hte freewheel's sprocket. Might need a mating ring on the other side for that. There's a lot of pics of this sort of thing in the non-hub-motor fourm section; should be at least one thread dedicated to it in the sticky thread index there, too.

There are also sprockets designed specifically for mounting htat way, as well as freewheels meant to accept them. Most of those seem to be made for scooters, and a lot of them use smaller than bicycle chain.


Keep in mind if you are using a bigger sprocket on the rear wheel, you are getting more torque, bvut less speed.
 
Holy cow, what do you need a gear that low for? Put that on a hub motor, and ride up hills slow enough to use that gear, and you'll smoke your motor for sure. It will take about 30-40 min.

60t in the back.. I mean really, that's going to be really crawling. The gear in the pic is for a front chain ring. But it may be possible to bolt it to a freewheel. It might require welding some tabs or arms to a regular freewheel gear to be able to get the bolts in. Or maybe cut away some smaller gears to get at the middle one better.

If you wanted a lower gear in back for a mid drive, that would make at least some sense. What you want makes no sense at all. I'm not calling you senseless, you just don't understand how hub motors work. Hubbies need to spin fast as possible when loaded heavy, or they just melt themselves.

If this hub motor is going to be a mid drive,, then I can start to understand what you want,, but 60t is still going to be such a high gear in that case, that again,, the motor will be spinning too slow.
 
Thats a pretty sweet sprocket! I guess if you were doing a mid motor and a hub motor you could go this route for gearing purposes. It looks like that sprocket requires some sort of cassette or free hub to adapt it. There is always a way
 
Well it's going to be used for when I pedal, and yes it's a very low gear which I intend to compensate by using a very small sprocket on the pedals side...
as to why? well, call me dumb but I want a sprocket big enough to cover my big hub motor from the right side, and if you are still asking why...well because I'm a perfectionist and the left side of the hub looks awesome because it has the 203mm brake rotor covering it, and the right side looks like a big ole ugly drum which can look sweet when it is covered by a huge sprocket + I love how the small sprockets look on the pedals axle better than the big ones.
 
Hey Dudes,

I know I know, it's the non hub and I'm posting a hub motor question...BUT after posting this question in the hub motor section, some guys suggested that i will ask here since non hub motors use many times a large single speed sprocket on the rear wheel.

So...
My hub motor has a single speed thread-on 16T freewheel.

I want to have a single 60T that looks like this: http://cdn.shopify.com/s/files/1/0573/2837/products/OneUp-Components-42T-Sprocket-green-3d-front-966.jpg?v=1443551991
and have it as a freewheel.

Is it possible?

I have seen conversions from cassette to single speed that use spacers but what I need is to have a single big gear to act as a freewheel on a 1cm thread on my hub motor (to replace the 16t freewheel that is mounted on my hub).

Any ideas on how to get this done without custom drilling and welding?
 
Are you setting up a dual motor ride? To have a mid motor drive the rear wheel via that 62T rear sprocket? If that is the case maybe it is easier to use left side drive and mount the big sprocket on the brake rotor mount? Then you ghost pedal along while cruising with the hub engaged, or enjoy the power from two motor where needed or in steep hilly situations.
 
If you must put the 60t ring on the freewheel side, this is a custom machining project. You'll need to get someone to make you an adapter ring that fits up to a Sickbikeparts.com 5-bolt freewheel, with a suitable chainring bolt pattern on the outer edge-- say 130mm x 5 bolt.

whitefw.jpg


If you don't want the one-way clutch feature, then you'll want to build the adapter ring onto a pattern drilled 22t fixed gear sprocket. Note that your sprocket will have to be screwed very tightly onto the hub if it is to be prevented from unscrewing under reverse torque.

surlycog.jpg


P.S. - This kind of simple plate part is cake for someone with a high power laser cutter or a waterjet cutter. It can be manually milled or CNC milled, but those are relatively high overhead processes to make this part.
 
rg12 said:
as to why? well, call me dumb but I want a sprocket big enough to cover my big hub motor from the right side, and if you are still asking why...well because I'm a perfectionist and the left side of the hub looks awesome because it has the 203mm brake rotor covering it, and the right side looks like a big ole ugly drum which can look sweet when it is covered by a huge sprocket + I love how the small sprockets look on the pedals axle better than the big ones.
Click to expand...

OK, that's dumb. Really dumb.

Do you really think that a gear you have to pedal around twice or more for each rotation of the rear wheel is useful for anything?

You need to realign your idea of what looks cool, is all.
 
Hmm...
What about this little thing?
http://www.ebay.com/itm/Bike-Metal-Scooter-Sprocket-Wheel-3-Speed-Freewheel-Spare-Parts-91mmx28mm-/401057828814?hash=item5d60e8cfce:g:5JgAAOSwoydWsxM0
Can I take the gears out of it? will a big cog fit on it?
 
I planned on using a much smaller gear on the pedal axle (whatever is the correct name for that) to compensate for the rear gear, sort of switch instead of big in the front and small in the rear have it big in the rear and small in the front.

Also, I rarely use the pedals at all but again, I wouldn't do it if I didn't change the gears in the pedal area to smaller.

and yes, the left side of the bike looks 200% more awesome than the right at the moment...

Mid drives look awesome due to not having that big ugly hub in the middle and also having that giant sprocket in the back but I'm not going mid drive anytime soon.
 
999zip999 said:
Don't mess with cool ,cool do as cool does. I guess you are not cool. Man. Coool it. Just to be Cool.
Click to expand...

Well I'm not looking for a 12yo cool (so other people will think it's cool) because nobody really cares what the right side of the hub looks like...
But I do, so why not?
I used to be a bodybuilder and people told me It's not cool anymore to be as big as I was but I never done it for anybody but me, so...

I get what you people are saying but it's still functional only different...looks better and doesn't hurt the functionality (again, using small gear in the front), it's not that I'm putting those fake brake rotors over my rear drums on my car to look "cool", it's functional, thus not stupid...

Why the hell would I build a downhill rig if I never go downhill? it just looks awesome...

Believe me, nobody would drive a Ferrari if it didn't look cool, doesn't matter if it went 400kmh in the corners...
 
rg12 said:
I planned on using a much smaller gear on the pedal axle (whatever is the correct name for that) to compensate for the rear gear,
Click to expand...

That's not compensating for anything! It exaggerates the problem. A single speed bike with a 60t rear sprocket would need something like a 150t front ring to have a normal all-around use ratio.

You're trying to make it resemble a motorcycle; I get it. But are you going to be able to turn the cranks at thousands of RPM like a motorcycle engine? No, you're not.

Put a giant ram air scoop and fake supercharger on it if you must. But set it up with a gear ratio you can actually use.
 
Hey, I'm not a fake guy man, that's not cool at all, I hate those "ricers" putting crap that don't work on their junk to look like real race cars...

Anyway, I guess I missed something...If for example I have a 20T in the rear and 50T in the front and I take 10T off of the front and add those 10T to the rear making it 30T in the rear and 40T in the front, wouldn't that stay the same?
 
The ratio between the front and rear is what your legs must work with. The absolute sizes of the sprockets is irrelevant to that ratio.

We have guys here who crave taller gearing than 53/11 so they can pedal along at motoring speeds. To have the same ratio as 53/11 but with a 60t sprocket in back, you'd need a 289t front sprocket which would be almost four feet in diameter.

Note that the lowest gearing ratio commonly used by pedal MTBers is 22/34. That's for climbing the very steepest grades you can balance a bike on. To get that ratio with a 60t rear sprocket, you'd need a 39t ring. And then you'd have a gear only suitable for the steepest grades you can ride on.
 
I see your argument now...so I guess I will scratch that idea...
I guess my hub will never look "cool" from the right side :cry:

Thanks alot for the help :)

Roy
 
Yeah, case closed, I thought it would work just like it is now but only look better so I guess since it doesn't work and since I'm not a poser putting things that don't work ONLY to look cool is not really my thing.

Thanks :)
 
btw, here they are showing off their better side :wink:
 

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rg12 said:
Anyway, I guess I missed something...If for example I have a 20T in the rear and 50T in the front and I take 10T off of the front and add those 10T to the rear making it 30T in the rear and 40T in the front, wouldn't that stay the same?
Click to expand...

No.
Keeping the same total number of teeth (20+50=30+40) will keep the chain length the same but will totally change the gearing ratio.

With a 20T in the rear and 50T in the front your gearing ratio is 20/50=0.4 which means every turn of the rear wheel requires 0.4 turns of the cranks.
If you wish to have the same 0.4 ratio with 3 times as many teeth in the rear (60T) you will need 3 times as many in the front (150T), 60/150=0.4

Avner.
 
Are you familiar with spoke protectors? They're discs that pinch between the freewheel and the hub to keep the chain from damaging the spokes in case of an overshift. They're not of practical use on a hub motor, because the spokes are located out of harm's way already. In the early '80s and earlier, they were usually made from stamped sheet metal. Now they're usually smaller and made from clear plastic.

It sounds to me like you could use either a big diameter spoke protector or a custom made equivalent part to dress up the right side of your hub motor to your liking. The ones that come to my mind are the well-finished, lightweight aluminum ones from Suntour back during the Carter administration. The center hole is 1-3/8" in diameter.

02130044-2.jpg
 
Just get an older yescom dd motor with it's aluminum swirl on both sides with a black background I don't have a pic but I bet wesnewell has one.
Thanks chalo this is educational.
 
Chalo:
I will look for something...that metal thing doesn't look that attractive...

999zip999:
Oh that is so ugly, I have seen those spiral looking thingies...It always makes the hub look like a toy.
fe5adafec86b5b32129a3d2da4aeb398.500
 
rg12 said:
BUT after posting this question in the hub motor section, some guys suggested that i will ask here
Click to expand...
I merged your two threads about the same thing into the new one. Please don't create multiple threads for the same thing. If you ever need to move a thread simply ask any moderator, either publicly in your thread or via PM.



FWIW, I don't see anyone suggesting that, anywhere in the thread. :/
 
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