what is a Jackshaft?

[DistantWolrld101]

I didn't answer the main question. No real advantage with a single speed unless you have serious chaining issues like on a fat tire bike.

Thank you that saves time for me then getting one on my new build unless i deiced to make it multi speed

 

[FNTPuck]

For 2strokes jackshafts are usually talking about transmitting the power to the pedal side so you can use a multi-speed bike for better low end and hill climbing ability. On a 4stroke, a jackshaft is usually used to increase gearing options by adding another set of gears to change ratios, or to offset the drive chain for wide engines or fat tires.

This is the one I made for my 4stroke since the TQ converter output sticks out around 1.5" too far. I didn't need it for the gearing in my case(although I did use it to gear it for a bit more top end), but to offset the output sprocket. Used a cheap(but modded) flux core so welds are kind of ugly, but strong.

 

[Frogslayer]

Nice work puck!

 

[FNTPuck]

Nice work puck!

Thanks! Its mostly the parts the big power gokarts used so its a bit overkill for most with the larger 3/4" axle instead of the traditional 1/2" and the thick 1/4" plate steel but I need it to hold a ton of torque safely and reliably without flexing.

Not happy with the bearings though, they seem a bit cheap so will be pressing in name brand sealed bearings once these start going (which I expect would be soon lol).

 

[Tyler6357]

A Jackshaft is set up to allow you to use the gears of the bicycle on the engine drive. Having gears is very helpful, allowing you to downshift to larger sprockets when going up hills and to smaller sprockets when on the flats to get more speed.