Gear Ratio and Jack Shaft Confusion......

Nice....Just curious tho BUT shouldn't the shock go up top?....Springs generally like to compress rather thank be stretched but I suppose if the spring is attached ( the ends of the spring held firmly or welded to) the shock body it could act in tension rather than compression.....it looks unconventional but it may work...

Hmmmm buy hey aren't motorized bikes for the most part unconventional too? I'm glad you are a tinkerer too!

Andrew
 
Yes, they normally should...
This is going to be a reverse cantilever set up. Meaning the main frame is bolted to the rearward bolt hole of the shock, and the rear tire cage is bolted to the forward part of the shock. Kinda hard to explain. It's an old motorcycle chopper trick. Picture 2 chain links enclosed and linked to each other. One is 90 degrees rotated to the other. The links can move freely, but cannot separate. Now put a shock between the area that the links both share. The brackets I'm building will be decorative, and be an artistic focal point of the bike.
I thought Flames would be the way to go.... =-]'

'BrettMavriK
 

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Gear ratios, and other boring tech stuff

Hello Brett, well I got to tell you Amigo, without giving away any trade secrets here are the ratios of the lil Chinese 2 strokes.

There is a 4.1 to 1 ratio in the clutch area of the engine. NOW take 10 to 44 and get 4.4 to 1. NOW take 4.1 TIMES 4.4 and get?

My calculator tells me 18.04, with admittedly a 26" wheel and tire, netting 6997 rpm, at 30 mph.

Your speed goals are unrealistic, without shifting, so it would seem.

Remember, Shifting is Illegal in ALMOST every state in Moped, and Motorized bicycle classes.

Mikw
 
my setup, ht motor 10 tooth to a 21 tooth on jack shaft, other side is a 10 tooth on jack shaft to a 16 tooth on the wheel(20" wheel). top speed of 25mph and climb about any hill.
 
Multiple ratios

HI Hillclimber, you have 4.1x2.1x1.6=10.08 BUT you have 20 inch wheel, very different and so much smaller than a 26, try the rolling distance of 1 rev and see.

Mike
 
Hello Brett, well I got to tell you Amigo, without giving away any trade secrets here are the ratios of the lil Chinese 2 strokes.

There is a 4.1 to 1 ratio in the clutch area of the engine. NOW take 10 to 44 and get 4.4 to 1. NOW take 4.1 TIMES 4.4 and get?

My calculator tells me 18.04, with admittedly a 26" wheel and tire, netting 6997 rpm, at 30 mph.

Your speed goals are unrealistic, without shifting, so it would seem.

Remember, Shifting is Illegal in ALMOST every state in Moped, and Motorized bicycle classes.

Mikw

Mike,
Sorry, man, but you didn't read the beginning of this post. You are calculating gears that I'm not even using. I am setting this bike up with a jackshaft that will serve as an intermediary between the cranks and rear wheel. I am also using a 3 speed internal hub. The gears inside the HT motor are 20/82, or 4.10:1; the countershaft off the engine is a 10t, and My rear hub is a 20t. There will be 3 gears on this jackshaft. One on the left connected to the 10t on the motor, one on the right connected to the rear hub, and another on the right with a freewheel going to the front crank. I have to not only find the right rpm range for my engine, but also for my legs, as both inputs share the last two gears to the rear wheel.
I think I have it ironed out on the 3 gears I need to have on the jackshaft:
a 24t, to a 22t, and then a 16t for the front crank.

This yields 33.3mph @ 5000rpm in 2nd gear (1:1) with 3rd gear to push into the high 30's, and lets me cruise at two cranks per second at 11mph in 2nd gear with again, 3rd as an overdrive.

Now the only thing that concerns me is if my rpm's are too low at that speed of 33.3mph and the engine won't have the torque to do it. If not, I'll put on a 28t on the left side of the jackshaft.

'BrettMavriK
 
brettmavrik, on your jack shaft, pedal chain side, free wheel to crank chainring and solid sprocket to back wheel should be the same size, number of teeth, that way you keep your current pedaling gear ratio. i have a 14tooth freewheel to the cranks,thats a 44 tooth, and a 10 tooth solid to the rear tire, witch has 16tooth freewheel, i can only pedal to 20mph max, my legs cant go no faster, but who wants to pedal anyway.
 
My rear tire has 5 speeds. I've nailed down the gears on all points that serve the motor as well as the pedals. I've got the perfect powerband gear for every rpm of the motor and every ppm (pedals per minute)

'BrettMavriK




brettmavrik, on your jack shaft, pedal chain side, free wheel to crank chainring and solid sprocket to back wheel should be the same size, number of teeth, that way you keep your current pedaling gear ratio. i have a 14tooth freewheel to the cranks,thats a 44 tooth, and a 10 tooth solid to the rear tire, witch has 16tooth freewheel, i can only pedal to 20mph max, my legs cant go no faster, but who wants to pedal anyway.
 
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