235/75R15
The full size blazer has 5.25 in the kick panel and 4 x 10's in the rear.
265/75R16
235/75/15 stock size
A 3/8 Allen key.
2.8 or 4.3
235/75/15
The factory size is: 225/70-15
look at the info sticker inside drivers door. My 89 blazer came with 31x10.5x15 from the factory.
The correct factory tire size for a 1998 Jeep Wrangler is 225/75/15.
there are two factory tire sizes for that truck. a 235/70R15 was standard, while a 235/75R15 was optional. you would need to have your VIN ran to find out which one your truck was built with. there is almost an inch difference in diameter between the sizes, and can result in a little over 3% speedo error (aprox 2MPH @ 60MPH)
there should be a factory tag on the drivers side door jamb giving factory recommended tire size.
As far as I can tell the front and rear speakers are 6-3/4 in