Front speaker size is 4x6, but you can fit up to a 6.5" as long as you make a custom bracket. This is much easier then it sounds. Just cut some 5/8th" particle board or MDF to size, mount your speaker, and you're good to go. If you go with 4x6 you should be able to use the existing plastic bracket just fine.
3.5 in tweeters in the dash and as far as i know my 2004 has 6x9s in the front doors and 6x9s in the rear shelf
Tweeters: 3/4in, Front: 6.5in, Rear: 6x9in
Front: 4x6 Back: 6x9
6.5 inches.
6.5 inch
Front 6X8 Rear 6.5
The speaker size for a 2004 Chevy Trailblazer is 6 1/2 inches. This includes the front, door, and rear speakers.
4x6 up front and 5.25 in soundbar
6x5 IN THE FRONT DOORS AND 4x6 IN THE REAR
pull the wheel off, remove the two caliper bolts, remove the caliper and the rotor can be removed
6.5" in the front, 6x9 in the rear.
The 2004 fits 6x9 in front and rear and 3.5 in the dash.