Spinning reels and Baitcasting are definitely different, but they both share some features. Gear ratio is a feature shared by Spinning and Baitcasting. You can choose the best shimano baitcasting reel.
The baitcasting gear ratio is how fast the reel takes a course, in other words, the number of times the spool turns in a full 360-degree arc. For example, a Baitcasting reel with a gear ratio of 5.4: 1 means that with one turn of the handle, your spool has turned 5.4 times. 5.4: 1 is a pretty standard gear ratio, so if you’re looking for high speed, look for a 6.4: 1 or 7.1: 1 ratio. On reel-spinning, the gear ratio refers to the number of times it rotates around the spool with one full 360-degree twist of the handle. For example, a 5: 1 gear ratio on a spinning reel means that by one full turn of the grip, you have turned your spool 5 times around. If you can afford to buy more than one reel, it is recommended to have initial speeds of 4: 1 (slow speed), 5: 1 (standard speed), and 6: 1 reel (high speed) in your arsenal. You can’t go wrong with just having a standard 5: 1 gear ratio, though, if you’re only looking to buy one reel darling
Line capacity is another feature of both reels. If you plan on fishing somewhere where longer resistance or underwater fishing is likely to occur – like saltwater fishing – you’ll want a reel with a high capacity. The thicker your line, the less distance your reel should occupy. Some reels are custom-made to use only a specific reel and the specification of the reels will tell you how many meters of the test they can hold. For example, the reel might have a line capacity of 180yds / 14lbs which means it will withstand 180 yards of a 14-pound test line.
Keep in mind this is only a guide and not precise as line diameters vary based on the type of material (monofilament, fluorocarbon, braided, etc.). When choosing line capacity, make sure the displayed capacity will be suitable for you based on the pound test you plan to use and how many lines you suspect you may need to spend. If possible, there is nothing wrong with increasing the capacity a bit as sometimes the fish throw more lines than you planned.