I think 6x9's would fit in the back. Try Crutchfield.com.
What size speakers go on the rear of a 2001 Buick lesaber
a 1991 buick skylark has 4" speakers in the dash and 6x9's in back
5.25"
they are 4x6 rear speakers are 6x9
The front door speakers in a 2003 buick century are 5 1/4 inches.
The 2003 Buick LeSabre has speakers in the doors of both the driver and passenger side. These speakers are generally about 15 inches.
6" x 9"
4 inch, 4x6, and 6x9
they used 4"x10"
fronts are 4X6 backs are 6X9
4x6 hard to replace!!!
5.25 or 5 1/4