4G model 1A Transmission only:

Grubee Inc


4G > 1A   Our most popular transmission.

Only (2) 1A Transmissions in stock as a separate order item. 

When these 2 trannys are gone you must order a 4G 1A transmission kit that also includes all the installation parts to install on a bicycle.   Yes; higher priced.  

4G Model 1A  T Belt Drive Transmission only;     

Latest Peak-a-Boo cover design:  

 Engine and bicycle are not included:

  • More compact for better appearance with an improved belt cover design:  
  • Best choice for single speed applications;  
  • Transmission Pulley Ratio: 20T x 80T = 1 to 4 ratio
  • 9T and 10T slide drive sprockets included for customer choice.. 
  • Final drive ratio depends on what drive sprocket and wheel sprocket is used.
  • Final drive ratio ie: 20/80T = 4     9T/48T = 5.3    final R = 4 x 5.3 = 21.2
  • Final drive ratio ie: 20/80T = 4   10T/48T = 4.8    final R = 4 x 4.8 = 19.2
  • Final drive ratio ie: 20/80T = 4     9T/56T = 6.2    final R = 4 x 6.2 = 24.8
  • The lower the ratio (19.2)  the faster you can go
  • The higher the ratio (24.8) the more torque for heavy set riders or for steep hills.
  • Cam lock tension system for belt adjustment means no belt idler is needed.
  • Peek-a-boo nylon/fiber glass belt cover guard.  
  • CC latch bell with dual ball bearings, No bushings: 
  • 80T Driven pulley also has dual ball bearings and freewheel. 
  • Built to last!