99cc rack mount 3 speed spoke drive MTB

Got some work in this afternoon and have the rods bolted in place keeping the swing arms from twisting. I also got the gear cable set up. The cable stop is from a cantilever brake and the hole in the bolt is large enough to allow two of the smaller gear cables to slip inside. Makes a nice way to join the original end with the threaded barrel to a new cable going to the throttle type gear shift. A short section of cable housing was added to extend the stock cable housing to the cable adjuster which was also salvaged from a cantilever brake. I'll trim down the cables once things are dialed in. Next thing is making up a catch for the drop stand and picking up cable clamps for the drop stand stop cables. Also did some figuring on the idler pulley for final belt tension. Using a coaster brake arm and spring loading it, I think. Getting there...
SB
 

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Lookin great, nice engineering!

For initial runs I would set the tire pressure at around 30lbs, this will allow some tread deflection to plant the spokes firmly in the tread knobs. This engine with the gearing it has can unload a gob of torque to the tire so set the hubs tension pretty high.

My take on setting the gear selection on the hub is to adjust second for perfect engagement. First and third will be automatically adjusted when second is perfect. Its a very fine adjustment on second slightly off either way and it will hunt in and out of gear which is hard on the hub.

Im excited to see this work for you should make a nice easy rider. Looks like your supervisor in the first pic may have doubts.
 
The Wonder Dog is just wondering about her kiddie trailer which I have not really been thinking about. The trailer and drop stand will probably not like each other much, so it may need to stay in an upright position while it is attached. Might be able to swing the trailer out to the side so the trailer arm is at a right angle to the bike while parked. Not real convenient. Might need to give more thought to an alternative center stand. She's also wondering why we aren't going for rides with the Panther so she can ride in her canoe sidecar. That's next up after this is a runner, which will be SOON.

Just from rolling the bike in and out of the wood shed I can see that this bike is a wheelie waiting to happen. The weight is poorly distributed with nothing up front and everything from the seat back. Care will be taken on the throttle, especially climbing hills and starting out.

Thank you for all of your help. I think we've got a winner with this spoke drive hub of yours...
SB
I've been wondering if there is a way to mate an in frame China girl engine to a seat post mounted hub spoke drive... possible? The engine would need to be reversed, wouldn't it?
 
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You probably have spare engines, otherwise I'd ask why not use one of the scooter type engines with a pumper (nearly typed pimper) carb on it and a minimoto type 3:1 reduction box.
 
Reducing to minimalism. why not just chop the entire back end of one of these off and use that to drive the tyre?

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Yeah, I believed we discussed the inverted CG engine in some thread earlier. Seems easy enough excepting the mount angles are reversed. A section of the proper sized tubing cut at the correct angle and welded to the frame would take care of that.
I would save my $$ and just use an S3X hub and run it like on my 3speed CG bike. I was riding that one this weekend and its one nice shifter. Far nicer than coping with the busy derailleur method. I was out riding the Cag bike and it works fine. Will be real nice in open run areas. In close areas with a lot of stop and go you are really working the shifter up and down the gears. Its a PITA in something like a panic stop where you don't have time to down shift!
 
I didn't get the inverted part until I dug out a China girl for a look. Oh, now I get why it would have to be inverted. I don't mind different, but that's just weird. I'll pass. Yeah, it would need a fixie hub. I have three China girls (triplets!) and was thinking about one on an old English bike I have, a Robin Hood, and was thinking it would make a cool friction drive. Which it would, but not with an upside down China girl mated to a salvaged S.A. hub.

What's the link to your 3 speed china girl bike? I'd like to look at it again.
SB
 
I had forgotten that your abbynormal 3 speed was chain drive to the rear wheel hub and was somehow thinking it incorporated the 3 speed hub as a friction drive. So much for that idea.
I could still do the Robin Hood with a China girl, but no gears, I guess, and no friction drive.
Ah well. Not that crazy about China girl vibrations anyway and the absolute last thing I need is another project... (slaps self)!
SB
 
Intrepid Wheelwoman said:
Oooooo you have a 'Robin Hood', - nice :D
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Yes, I found it at the dump this winter in okay shape. It is a blue step through. Needs a few things and some TLC. Paint and decals are pretty good. I would leave the paint alone. When I was a little boy I was a faithful viewer of the British import series Robin Hood starring Richard Greene which aired every weekday when I got home from school in the afternoons. Bows and arrows & horses. A winner! So when I found this old bike I had to bring it home and tuck it away as a way of honoring childhood, which in my case is ongoing. I have a front wheel bikebug friction drive engine which is complete (kind of like a Solex) and it would be more appropriate than a China girl. With the engine disengaged it makes a good rider. So that's probably what will happen to it. Sometime...
SB
 
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bowljoman,
What an interesting setup that is! If I were 20 instead of 70 I'd want one of those. And do I spy an IGH as a friction drive wheel? Does putting weight on the scooter engage the roller to the tire? Can you tell about it or is there a thread for it somewhere?
SB
 
Silverbear, its chain drive from the IGH, but that is a novel idea to lean back and go. I understand it looks freaky, but the wheel base is over 60 inches and it rides as true and solid as a horse. Ill have to dig up the thread for my build.

Ludwig, check your local laws for motorized foot scooters. Generally they are legal where motorized bikes are accepted. We dont need no stinkin peddles :)

In washington, bikes do require peddle starting and cannot have shifting gears, and are limited to roads 35mph or less except state highways where motorized bikes are allowed.

Versus foot scooters, cannot have a seat or peddles, cannot shift, cannot exceed 25 mph and must stay on roads 25 mph or less, except state highways where foot scooters get equal access.

Pick your law-breaking camp....
Either you have a bike with peddles and an engineering problem of bump starting the IGH. We cant have pull starts as far as I can recall, but having the shifter makes the bike illegal around here anyway.

..Or you have a shifting foot scooter that exceeds 25 mph, but must avoid arterial streets.

Some places allow auto shifting bikes like we have seen built here as opposed to manual which accommodates CVT's on mopeds.

Im not trying to discourage using a bike and advanced IGH engineering, and admittedly I do like a foot scooter for hitting 40mph with the IGH... My point is once you cross the line into outlaw biker, stop limiting your build ideas with the law of requiring peddles or other laws. After all, you'll have explaining to do either way if an officer of the law is hip to the finer points of motorized vehicles in our class :)
 
I think that is very cool. It looks like it would be a whole lot of fun to ride. 40mph? What a rush that must be! So, it has a centrifugal clutch? And you let off on the throttle while shifting?
SB
 
silverbear said:
I think that is very cool. It looks like it would be a whole lot of fun to ride. 40mph? What a rush that must be! So, it has a centrifugal clutch? And you let off on the throttle while shifting?
SB
Click to expand...

yup. the onnly sticky part is down shifting. the nexus wont down shift under heavy load, but it will upshift. I purchased an imotion hub but have not modified it. IM using the stock tricycle IGH that comes with two sprockets.

A serious rush! I dream of adding a expansion pipe and high flow carb.
 
I accelerate to the max HP rpm and release the throttle. as the engine slows I shift it up. Generally and ideally, the max HP rpm is the same road speed as the max torque RPM of the next higher gear. I execute the shift and hear a clunk but the shock doesnt affect the engine rpm. It just clicks, and then I gun it.
 
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