Jackshaft Better than Jackshafting?

[machanic]

Do I get that right an XR50 pumping out 50HP, that's got to run on fuel, and I asked about the BB size because if you have the 52mm dia. it is really easy to make a BB jackshaft, the problem is dropping the chain down on the china girl engines.

 

[KCvale]

mechanic - I'm not associated with BikeMotive, I simply posted Mel's work here to show what the OP had in mind is/was already being done in the electric bike world.

Seems silly to me, shifting E-bikes are easy.

You simply don't need or want a front derailleur.

 

[Barnfresh]

Seems silly to me, shifting E-bikes are easy.
You simply don't need or want a front derailleur.

Personally I wouldn't want a rear derailleur either, especially considering the many internally geared rear hub options that are available.

 

[Barnfresh]

Do I get that right an XR50 pumping out 50HP, that's got to run on fuel, and I asked about the BB size because if you have the 52mm dia. it is really easy to make a BB jackshaft, the problem is dropping the chain down on the china girl engines.

Yeah I think I mentioned that problem with the China Girl chain alignment (left side bottom bracket jackshaft) in one of my earlier post, that along with just flipping the engine around like you're doing only inverting the engine and change the crank shaft rotation. I saw photos and video of one that was done that way and run through an internal 5 speed rear hub. It was a ripper until they broke the frame. I'll try to find it and post some links.

My hotrod XR50 likes VP Race fuel, Min 95 octane otherwise it will overheat. Right now I have the vacuum operated secondary disconnected so it's probably nowhere near the 50hp it's capable of in a fully tuned state. The good thing is with the secondary disconnected I can run it wide open if I want to without worry about blowing the engine up.

 

[Frankenstein]

Kc, you do understand there are people who would, and could, and do ride electric bikes with their legs. Actually a lot of people just get the motor to make going up a hill way way easier on themselves, and then enjoy the bike in manual mode.


A crank shifter allows a person to keep a canter a bit easier since it spreads the gears out a little more. I s**t you not people actually still ride bicycles with their legs these days.

 

[FurryOnTheInside]

Kc, you do understand there are people who would, and could, and do ride electric bikes with their legs. Actually a lot of people just get the motor to make going up a hill way way easier on themselves, and then enjoy the bike in manual mode.


A crank shifter allows a person to keep a canter a bit easier since it spreads the gears out a little more. I sh*t you not people actually still ride bicycles with their legs these days.

... Also straighter chainline, more even tension, wider gear range.

My rear derailleur can take up the 23 tooth difference between the 42:34 (10mph @100rpm) low gear and the 42:11 (26.5mph @100rpm), but it's much better to shift to the 52:14 equivalent gear and have less slack chain and a straighter chainline, as well as the ability to then go all the way up to 52:11 (38mph @100rpm).

Having a 30t as well is a sort of safety feature, ensuring that I can still get home even if the engine fails or I use up all the fuel and have to rely on pedal power alone to get up hills.

 

[KCvale]

I like an internal shifting hub too, 3 or 5 speed is fine.



That bike can be pedaled with no power and virtually no drag and you can pedal along, pedal backwards when passing other bikes, or pedal to help the drive, or don't pedal at all ;-}

Those are all 3-speed internal shifters.

 

[machanic]

I like an internal shifting hub too, 3 or 5 speed is fine.



That bike can be pedaled with no power and virtually no drag and you can pedal along, pedal backwards when passing other bikes, or pedal to help the drive, or don't pedal at all ;-}





Nice looking machines but will they wheely!

Those are all 3-speed internal shifters.

 

[KCvale]

Also note those bikes were all just coaster brake which of course is rendered useless so I they all got independent front and rear C brakes.
And yes, they can pop a wheelie, I have to warn my customers about that.

 

[machanic]

Also note those bikes were all just coaster brake which of course is rendered useless so I they all got independent front and rear C brakes.
And yes, they can pop a wheelie, I have to warn my customers about that.

You got to love the off the line torque of geared electrics.