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A new Geared Experiment idea maybe?

C

cheap ride

Guest
Been reading on the forum of all the ways to gear our engines without to much cost, Here's my idea, Instead of puting the internal geared hub on the back wheel (logical place) why not locate it directly behind the output sprocket from the engine? then attach another sprocket very close to the sprocket on the geared hub, sitting together side by side, so output from engine to geared hub sprocket , then to neighbour sprocket, then directly back to our standard spoke mounted rear wheel sprocket. That's it , Is that great or what? , No jack shaft to stuff with, complete left side geared drive.

One small problem that i'm sure we can overcome quite easily, The sprocket teeth on the geared hub sprocket are obviously for bicycle chains, change this one sprocket to a sprocket with our 415 tooth spacing and that's it.:)

Also would a cheap Sturmey Archer 3 speed Internal geared hub for $52 U.S. do the job? I think they give a %133 total ratio change.We can always manipulate gearing outcome by using different size rear sprockets and hub sprockets. :) comments please.
 


5

5-7HEAVEN

Guest
:cool: The first hurdle is the fact that the internal gear hub is built for right-side drive and left-side coaster-brake.

If you were to affix a left-side sprocket on the hub, you would not be able to take advantage of the internal gears. If you reversed the hub, the sprocket would not spin CCW. It would lock up, because of the coaster brake in the hub.

In essence, the hub you mount behind the engine sprocket becomes the jackshaft. using two sprockets means that the engine needs to shift outwards on the left-side, to align the inside sprocket with the rear sprocket.

ORR, align the engine with the inside sprocket and use OCC STINGRAY sprocket adaptor to move the driven sprocket slightly outward.

I am doubtful if this arrangement would work the way you described. However, keep thinking. you might be on a good track.

It is a good theory, and if it worked, it'd be like happy time engine with a 48-tooth sprocket and a 36-tooth sprocket. that computes to great low end gearing AND awesome high-end ratio.

Myron
 
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A

andyinchville1

Guest
Hmmmmm,,,,I think that mounting the hub backwards (so that the sprocket of the Sturmey is in line with the engine sprocket will NOT work because at that point tie Sturmey will be freewheeling....There was and old Sturmey that was a FIXED multispeed hub that would solve the freewheeling issue but they are no longer made...modding a new Sturmey can be done but requires disassembly and machine work / possible fabbing (see Sheldon Brown's site I think they have a link or article on making the hub FIXED...i.e. non freewheeling)...

As far as 2 sprockets side by side on the same hub shaft...I am not sure that that would apply the multispeed capability of the hub into the drive train to be applied to the rear sprocket....The other sprocket would probably have to be fixed to the hub shell itself for this to happen ( I think this is what you meant though...the 2 sprockets just cant be mounted to the SAME shaft)....At this point, the other concern I could think of might be chain angles and the chain clearing the rear tire.....That is because if you align the drive sprocket of the Sturmey perfectly the the output of the engine, the fact that the other sprocket on the has to be mounted to the hub itself for the hubs gearing to be useable
the chain at that point may be too far inboard when making a straight line to the rear tire for the chain to clear?...offsetting the hub to the left (while seated on the bike) may help with alignment issues but if using a happy time or similar engine the concern would be to not have the chain rub the inside of engine sprocket cover....of course that could be modded to if needed.....Hard to say about chainline issues without actually trial fitting to a bike or your particular bike....

Sprocket would not be a problem to make (see list of supporting sponsors ;-)....)

Hub mount would have to be custom fabbed.....

I believe the idea sounds like it should work (unless I misses something too) BUT would require a fair amount of modding....

By all means try it and keep us all posted....I am not 100% sure if there is anybody here running a multi speed setup yet.....It would be neat to be possibly the first huh?

Andrew

Andrew
 
A

andyinchville1

Guest
Oh...because of 5-7Heaven's post be sure to get the non coaster brake model....I didn't think of that earlier....That could have been another possible problem ;-)

Andrew
 
A

andyinchville1

Guest
Hmmmm....wow brain is burning now....if you try to drive the right side under engine power
you WILL need to make sure to have the human powered portion on its own freewheeling system of some sort so your pedals won't spin while under engine power (you could check out Staton's Site on how they use a Right side drive for engine powered applications while having the rider able to pedal or freewheel.. It is a simple little adaptor piece they make/sell)...but anyways that assumes you wanted right hand drive....

Wow....I like this multispeed stuff but gotta eat before I pass out!...

I like the simplicity of the original idea although it still does require alot of work !

Either way go for it cause tinkering is half the fun.....BUT the real fun starts if it works!

Andrew
 
M

minibiker

Guest
if any ne 1 made a left side geared hub with a peddle optoin they would make a bank!!!
 
G

Ghost0

Guest
Funny you should ask about the left side geared hub option. My dad and I are in the process of designing that very item. We should have prototypes by the beginning of the year. We may even ask of few of the members to try out a few of the prototypes to get some feedback. I will keep all up to date as the project progresses.
 
5

5-7HEAVEN

Guest
:cool:STATON makes a 16t left-side freewheel sprocket, to be used with their HD hub. To utilize this driven gear, one would reverse the chainwheel and swap in/modify a 32-tooth crankset sprocket to maintain 1:2 cruiser bike gear ratio.

Gears are turning in my head. I have another theory to explore in "geared experiments.":rolleyes:

Myron
 

iRide Customs

Member
Joined
Apr 27, 2007
Messages
897
I've done this and it works but you have to have a freewheel hub for the jack shaft. If you had that you'd need a pull start on you engine. I'm not sure how long the internals of the hub would hold up to the forces of the motor. I used a Shimano on this bike. Sturmey Archer makes a very inexpensive 3 speed freewheel hub...I think it's about $60 with a shifter. If you use a disc compatible rear hub you could just bolt a 44t where the rotor would be bolted on. I've done that too and it works great!

Dan
 

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C

cheap ride

Guest
Thankyou all

Wow, what a great bunch of knowledgable people, i'm so glad i found this forum, so many people, willing to devote thier experience and knowledge in helping others with likeminded interests, love that chopper dan, superb craftsmanship,quite artistic, and that seat, simple, buitifully crafted.

Now you have further inspired me to venture back to my shed and try to create what you guys have done so well. thankyou all for your advice and input. adrian, Perth, Western Australia. incidentally it was 39.8 degrees celcius yesterday, a tad to hot for the shed.:D
 
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