Jackshaft or Not?

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Shameless54

New Member
Sep 11, 2010
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Lewisville, Texas
Okay, I have a Schwinn Badlands Mountain bike to install a 66cc engine on . . .

Is the only reason folks put on the jackshaft so they don't have two long drive chains? Maybe better gear ratio efficiency?

It seems like you should still be able to switch gears with the motor engaged without a jackshaft, right?

Shamelesszpt
 
bluenosegoat

bluenosegoat

New Member
Dec 29, 2009
259
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arizona
with out a jackshaft set up your gears are useless except for pedaling. I have the SBP kit on one of my mountain bikes and love it! I use this bike as my work horse to pull my daughter and everything else in a trailer and having the gears is wonderful. I also like to cruise without the engine at wide open throttle.

The standard rear kit sproket works indipendently from the pedal chain- the engine power is sent to the wheel on the left not on the right through the pedal chain.
 
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KCvale

KCvale

Well-Known Member
Feb 28, 2010
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Phoenix,AZ
I Jackshaft to a 3-speed hub and love it.

These pics give you an idea of how they work.





Is your Schwinn Badlands Mountain bike new?
Does it have the front shocks, 21 speed, and Shimano STX gears?

If the derailer and rear hub are in good shape you should be fine, but you won't get 21 gears and you will have some work to do.

First you will pull off the whole pedal crank system and front derailer system and controls, that whole thing is replaced with the one in the kit so you will only have the 7 gears on the rear.
That is not a bad thing, heck, a 3-speed hub is worth it.

Then, you will want to move the rear shifter control to the left, and get Sick Bikes dual pull brake lever when you order the kit.

When it's all said and done you have the throttle and single brake lever on the right, the clutch and gear shifter on the left.

I'll be happy to give you riding tips if you go that far, and I'm sure others like Pablo will as well.

Currently I am trying to finagle a way to use the new version of the SBP Jackshaft and the new NuVinci programmable fully automatic 64-speed hub* in my next Luxury ride.

That is a whole new can of worms however as I want to take it to extreme.

The goal is to put a 66cc 2010 Grubee with an SBP X-chamber on a sturdy bike frame with a perfectly programed automatic NuVinci hub and beat the pants off a 5-speed manual 125cc dirt bike in any kind of street race or other competition like pulling power, and be able to ride it legally on the road without a drivers license, tags, insurance, bla bla bla... And not even have to manually shift it.

Expensive sure, but you can't help but ponder how cool that would be ;-}

*fully automatic 64-speed hub
Actually you program it do whatever you want up to like 256 speeds, but that would be silly on a MB, I am thinking a dozen would be just dandy but you have to read up on that hub to understand.
 
mobike91

mobike91

Member
Sep 14, 2010
111
2
18
lebanon, oregon
what about a really high geared bike? like first gear going so slow you could walk with it?
think those sbp kits allow that much gearing? and if it could gear down, would it be able to handle those amounts of tourque?
 
BarelyAWake

BarelyAWake

New Member
Jul 21, 2009
7,194
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There are are number of primary gear options available for the shiftkit for exactly that reason - 21sp bikes are commonly converted (giving you 7 gears for the engine ofc) yet I've a 70yo cruiser w/e 3sp hub & a shiftkit, about three times the weight and less than half the gears lol - yet swapping out the freewheel chainring from a 44t to a 48t fixed me right up!

I think dialing in the gearing for your riding style & bike is half the fun lol ;)
 
KCvale

KCvale

Well-Known Member
Feb 28, 2010
3,966
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Phoenix,AZ
BarelyAWake said:
I think dialing in the gearing for your riding style & bike is half the fun lol ;)
Click to expand...
I agree BA.
I feel like a kid in a candy store with the possibilities for 'gearing' the NuVinci fully automatic programmable hub I have coming without even getting my hands dirty to match the motor on my next build via my PC or laptop.

I think total range is .5 to 1.8 total range from drive ratio with as many automatic shift points as you want in between.

As far as a bike geared low enough to be powered at waking speed, a mountain bike with a huge rear 1st gear sprocket should be able to pull that off, but as BA mentioned, you can always make the drive sprocket smaller pretty easy.
 
mobike91

mobike91

Member
Sep 14, 2010
111
2
18
lebanon, oregon
well thanks guys. i figured i would get some good answers on that one. i want to gear it down enought to climb some pretty steep hills without to much effort, and go thru some nasty stuff and spin the tire too XD haha. mudd. cant live with it, cant live without it lol..
 
Sidewinder Jerry

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
2,008
949
113
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Rockwood, TN
KCvale said:
I Jackshaft to a 3-speed hub and love it.

These pics give you an idea of how they work.





Is your Schwinn Badlands Mountain bike new?
Does it have the front shocks, 21 speed, and Shimano STX gears?

If the derailer and rear hub are in good shape you should be fine, but you won't get 21 gears and you will have some work to do.

First you will pull off the whole pedal crank system and front derailer system and controls, that whole thing is replaced with the one in the kit so you will only have the 7 gears on the rear.
That is not a bad thing, heck, a 3-speed hub is worth it.

Then, you will want to move the rear shifter control to the left, and get Sick Bikes dual pull brake lever when you order the kit.

When it's all said and done you have the throttle and single brake lever on the right, the clutch and gear shifter on the left.

I'll be happy to give you riding tips if you go that far, and I'm sure others like Pablo will as well.

Currently I am trying to finagle a way to use the new version of the SBP Jackshaft and the new NuVinci programmable fully automatic 64-speed hub* in my next Luxury ride.

That is a whole new can of worms however as I want to take it to extreme.

The goal is to put a 66cc 2010 Grubee with an SBP X-chamber on a sturdy bike frame with a perfectly programed automatic NuVinci hub and beat the pants off a 5-speed manual 125cc dirt bike in any kind of street race or other competition like pulling power, and be able to ride it legally on the road without a drivers license, tags, insurance, bla bla bla... And not even have to manually shift it.

Expensive sure, but you can't help but ponder how cool that would be ;-}

*fully automatic 64-speed hub
Actually you program it do whatever you want up to like 256 speeds, but that would be silly on a motorized bicycle, I am thinking a dozen would be just dandy but you have to read up on that hub to understand.
Click to expand...
KC I followed the Nuvinci story and am familiar with the results. Still have you seen this bike here?

http://evolvethebike.com/

Let me know what you think. I wonder if they'd just sell the shifting system. Just not crazy about an aluminium frame bike.
 
KCvale

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
LR Jerry said:
KC I followed the Nuvinci story and am familiar with the results. Still have you seen this bike here?

http://evolvethebike.com/

Let me know what you think. I wonder if they'd just sell the shifting system. Just not crazy about an aluminium frame bike.
Click to expand...
Interesting, a NuVici 360 with their own rather compact shifting servo and the front hub gen to power it is a nice touch and even though the bike is a whopping $1,000 what would kill JSing it the sensor/controller, it is mounted to the chain guard just behind the BB sprocket.



With dual sprockets on the front you might be able to cut the chain guard and keep it on, done that many times, but you would need to come up with an alternative way to mount that controller to the frame and it doesn't look like they give you any extra wire for movement and it has some kind of 3 button controller mounted on the top tube, level of pedal power you want to use I'd guess.

Interesting to say the least but not anywhere near worth $1K for just the bicycle, I build kick butt manual shifters for that money including the bike.
 
M

mirage

Member
Oct 31, 2010
79
0
6
england
i have fitted a shimano rear bicycle hub to the drive shaft of my huasheng, now i have a choice of bmx single sprockets. with the shimano splines of course, i used polyform plastic to mold around the shimano hub to hold the sprocket up against the shoulder of the hub, then using the normal screw cap to press it up tight. remember to leave 15thou gap, ie cap unscrewed by this amount when you mold the plastic aroung the hub. so that it will be able to press the plastic spacer and sprocket up tight, no wobble. there are other difficulties with driving the system from the drive shaft, ie. the shimano bush is hardened steel, more on that later if interested, if you could get a large rear bicycle sprocket the possibilites get interesting. multiple gears.
 
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16v4nrbrgr

16v4nrbrgr

Active Member
Mar 17, 2012
1,728
4
38
North Bay
I had issues with torque stripping the three nub splines off the hardened sturmey 3 speed sprockets on my electric. The cassette or threaded ones might be a better option because of that difficulty with the sprocket similar yours.
 
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