How to tweak a baitcasting reel
I'm sure things have changed in recent years, but trial and error was the only way to learn how to tweak a baitcaster during my learning days. The instructions in the box never had any useful information and we didn't have an internet to search for articles. I'm writing this article so you can quickly learn what took me a lot of trial and error to figure out.
This article applies to most baitcasting reels. Since about 2007, I've been using primarily Ambassadeur Revo reels. They are very good quality reels, with a wide range of models. As far as I know, all Revos have the same shape and size. I highly recommend the Revo. However, before 2007 I used mostly Shimano reels - and they can be tweaked the same way. They made a great reel (and still do). But I haven't kept up with all of them since I went to Revos. I'm sure most other baitcasters work the same way.
This article assumes you are using right handed baitcasting reels. If you use left handed reels, everything should be just the opposite. This article also assumes that you already know how to throw a baitcasting reel. If you don't have experience casting a baitcasting reel, read my article on how to throw a baitcasting reel. The articles compliment each other.
Fill them full
The most important (and most often ignored) factor in setting a baitcasting reel is to fill it full of line. I like to have my reels so full that if I put any more on it, it will bind up on the sides. If it does bind on the sides, it is too full. However, it is better to overfill it and have to remove some than to short yourself on every cast.
Let me explain the importance of filling it full. The main reason is that you will get longer casts. If your line is full, your spool doesn't have to turn as many revolutions to get the distance. A rule of thumb I have come up with is that the percent of how full you fill your reel is about equivalent to the percentage of your maximum casting distance. For instance, if you fill your spool 100%, your maximum casting distance is 100%. If you fill it 80%, you can only expect to throw it 80% of its' potential. Likewise, if you fill it 50% full, you can likely throw it to the end, which is about half the distance you could get if it was full.
Another reason for having it full is because it is the only way you can be consistent. If you fill your line 80% full and get it tweaked for that amount of line. Later, you get hung up and cut your line - now you are at 60%. Your settings are now too tight, so you loosen your reel so you can get your maximum distance (which is about 60%). You later fill your line full and don't tighten your settings. What can you then expect? You guessed it! You can expect a big backlash with your brand new line.
How do you prevent inconsistencies? Well, you can't totally prevent inconsistencies, because line changes after it gets wet and after it has been used. But you can be fairly consistent by filling your line full and not letting it get low. My rule of thumb is to change my line when it gets below 90% or when the line gets looking bad. When I replace the line, I don't leave any line on the reel unless I'm using mono for a backing for braid (if you tie braid directly to the spool, it will slip).
There may be reels that are exceptions (but not many) to the rule of filling them full. I had a Shimano Corsair reel that I got because of its large line capacity. I filled it full and couldn't get it tweaked until I took about 20% of the line off. But most spools are the perfect size and should be tied directly to the spool and filled full.
Setting the brakes
Setting the brakes is very simple on the low profile styles of Shimano and Ambassadeur reels. Just remove the cover on the left side and pull out one of the 6 plastic weights to tighten the brakes or push it in to loosen the brakes. Revos have a knob on the right side that are usually finger tight (but could require a screwdriver to loosen). It must be loosened before the left plate can be removed. The round style Shimano reels (Corsair & Calcutta) are a little more complex. The brakes are in the same place and they are basically identical, but you must remove the spool from the right side of the reel to get to the brakes.
Many reels have brake control knobs on the left side of them (usually instead of centrifugal brakes). In most cases, you can tweak them by following the same procedures as the brakes. They will usually have +/- or more/less written on them. "+" or "more" usually means more brakes - not more distance. So, don't get that confused. Also, don't get the brake confused with the friction adjustment. All baitcasting reels that I ever use have a friction adjustment between the spool and the handle.
Tweaking the reel
To tweak the reel, first fill your reel full with line. Then tighten the friction control knob (located under the star drag control) on the right side of the reel. You don't want it finger tight, just tighten it until it is just tight enough for a bait to slowly drop. It's better too tight than too loose. Start with 3 brakes out and 3 brakes in. Cast your lure fairly easily, but not against the wind. If it backlashes before the bait hits the water, you need to pull out a brake. If it backlashes after the bait hits the water, either you released too late (which you will almost certainly do the first time you cast it overhead) or you need to tighten your friction control knob.
If you didn't backlash on the cast, try again a little harder. If it still didn't backlash, push in another brake and repeat the process. You want to find the point where if you pushed in one more brake it would backlash before the bait hit the water. The only way I know to find that point is to push them in until it does backlash (before it hits the water) and then pull one out. That point will usually be 1 to 3 brakes out on a calm day and 2 to 5 brakes out on a windy day. If you are able to fish with no brakes out, you probably don't have enough line or your reel needs maintenance. Most of my reels have 2 brakes out. When I have beginners, I will often need to set it to 3 brakes. Likewise, if I'm fishing a tournament or for some reason my clients aren't using my reels, I will sometimes have them set with just one brake. When I have a reel perfectly tweaked for me, it will be too loose for most of my clients.
Once you get it tweaked to where it would backlash if you pushed in another brake, then you do any adjusting with the friction control knob on the right. Loosen it to get more distance, or tighten it to keep it from backlashing.
Keep in mind that your reel will let you know if it is too loose, but it won't tell you if it is too tight. You may set it for a windy day and when the wind dies down you could be getting much longer casts if you pushed in a brake or two. Likewise if you have it set for a full spool and you lose some line, it will then be too tight.
How tight you put the brake cover on (reels that don't snap into place) will also make a difference on some reels. Tighter will slow the spool, while looser will make it spin (and backlash) easier. I believe most manufacturers are getting away from the variable adjusting brake covers.
Setting the drag
Setting the drag can mean the difference from catching or losing a fish, so it is very important. In case you didn't know, the big star next to the reel handle is the drag setting. Clockwise tightens the drag while counter-clockwise loosens it. I like to get the fish in the boat as soon as possible, so I normally keep the drag as tight as I can get away with. If I am using 30 pound test, I don't want the drag to slip unless a big fish turns away right at the boat. If I am using lighter line, I want it to slip so it doesn't break the line.
What I do is put my thumb on my spool (pushing down hard on the line) and hold it tight to keep it from turning. I then turn my reel handle. If my drag is too tight, I can't keep the spool from turning - so I will loosen it counter-clockwise. If it is too loose, I can hold the spool and easily turn the handle without the spool turning - so I will tighten it clockwise. This is basically the same as trying to pull the line to see if the drag will turn, only it doesn't dig the line in the reel. You may still want to pull the line to test it - just to make sure it is set right. Be sure to check it fairly often - especially if someone else uses your reel. I often set the hook on a fish later to find out that one of my clients loosened the drag so much that I couldn't get a hookset.