need help with shift kits and drifters

Kraash · #1 (**permalink**) 07-31-2008, 05:40 PM

what are shift kits all about... i dont realy understand how the engine gos without the pedels going around in the first place. how do the shift kits work?

and what about single gear bikes with rear drifter breaks? can those be used for the motor mod? do you keep that rear break functioning?

**Bikeguy Joe** · #2 (**permalink**) 07-31-2008, 06:23 PM

The shift kit effectively adds a transmission to the china based in-frame engine kit. With a coaster brake, you mount the kit and have one speed just like any other bike. With the shift kit you are using the bikes original drive system as where without it, you are running an ancillary drive system.

Kraash · #3 (**permalink**) 07-31-2008, 06:44 PM

whats better, why?

will the pedel break system work with a motorbicycle?, or would i have to mod it and add brakes?

Pablo · #4 (**permalink**) 07-31-2008, 07:37 PM

Quote:

Originally Posted by Kraash

what are shift kits all about... i dont realy understand how the engine gos without the pedels going around in the first place. how do the shift kits work?

and what about single gear bikes with rear drifter breaks? can those be used for the motor mod? do you keep that rear break functioning?

Pedals don't turn with engine power, because there is a supplied freewheel and chainring (and spindle and cranks) for the front. The kits work by taking the engine power through the newly shortened kit chain driving a custom made sprocket (all on the left side) connected to a jackshaft, over to the right side and another custom made chain sprocket down via a BMX chain to the chainring/freewheel to drive the normal bike set up.

This set up will not work with coaster brakes, and if the bike is a single speed, there is not much to be gained with a shifter kit.

Shift Kit Info

Bike Requirements

Kraash · #5 (**permalink**) 07-31-2008, 10:20 PM

than how does one get around the pedel break system?

Pablo · #6 (**permalink**) 07-31-2008, 10:32 PM

If your bike has the correct welded bracket, you can add brakes.

**Bikeguy Joe** · #7 (**permalink**) 08-01-2008, 09:07 AM

Why "get around them"? They work reliably in all the bikes I've built.

If anything, you would want to augument them with front brakes.

Kraash · #8 (**permalink**) 08-01-2008, 04:40 PM

i guess i still dont understand shifter kits.. if it drives the same chain that you use to pedel why dont the pedels wip around at 2000rpm when you release the clutch?

Pablo · #9 (**permalink**) 08-01-2008, 04:46 PM

Quote:

Originally Posted by Kraash

i guess i still dont understand shifter kits.. if it drives the same chain that you use to pedel why dont the pedels wip around at 2000rpm when you release the clutch?

Simply because there is a freewheel in the front. It comes with the kit.

Sheldon Brown's Bicycle Glossary E--F

Sick Bike Parts Shifter Kit

Paul

datz510 · #10 (**permalink**) 08-01-2008, 04:46 PM

Same reason you dont have to pedal all the time when riding.. there is a freewheel mechanism in the new pedal assembly that is basically a one way bearing. It allows the chainring to travel faster than the pedals (so you can keep the pedals stationary if you want) while the engine is propelling the bike. If you want, you can pedal. Once your feet get to the same rpm as the chainring, the one way bearing locks in place and allows you to assist the motor.

Pablo or Ghost0, you guys ought to take some video of how the system works.