[Swebike]

What´s size is the passenger speaker GL1800-05

 

[Mockin]

4 1/4", but you can Doctor a 5" Car speaker in there for better sound.

 

[Lewis/EC]

It is actually a bit larger.... 4.5" and a pincushion basket.

 

[pearlblue1800A]

rear speaker

Check out the J & M audio web site "jmcorp.com"
The speakers offered by this company are specifically designed for the GL1800.