The longest casts are made with the smaller reels like the ABU 6500 series and Daiwa 7HT. All these reels have a spool made from lightweight alloy. This is important because it's the overall weight of both the spool and the loaded line that we must control during the cast. The more the combined weight of spool and line increases the harder it is to slow the spinning spool down during the leads flight.
Consider only reels that have an alloy spool for any powerful casting and long range work. Each season sees anglers trying to master cheap metal spooled multipliers with inevitable consequence. Heavy metal spools, unless you over brake them which defeats the long casting process, are impossible to tune for serious fishing.
These named reels have small brake blocks which sit on a length of stainless steel rod pinned through the spindle of the spool. These blocks, when the reel is assembled, run around the inside edge of a metal ring. It's a similar principle to the brakes on your car. The blocks in contact with the rings surface add a braking effect to the spool, especially at the outset of the cast when the spool jumps from standstill to full speed as the lead is released. This initial control is the main function of the blocks.
The actual brake blocks are made from plastic, or in the past fibre. They usually come in three sizes, large, medium, and small. Large blocks with the bigger surface area provide more braking than the smaller ones. Remember this last sentence for it is the key to easy tuning.
A secondary braking system is required for when the spool is in mid cast, still revolving rapidly, but the lead is slowing down through air pressure. This is a critical time for backlash to occur. The line is spilled from the spool quicker than the slowing lead can keep it tight. Loose coils of line coming off the reel are not pulled through the rod rings quick enough and become entangled with new coils of reel line catching them up and the ensuing tangle creates a birds nest of line and the lead cracks off.
This secondary system is oil of varying degrees of thickness that when applied to the spool spindle slows down the speed at which it can revolve. The thicker the oil used, the slower the spool turns. Some modern oils can change viscosity as heat increases, though this is debatable in a reel context.
Cheaper multipliers will have phosphor bronze bushes for the spool spindle to spin in. Better quality ones will have a series of ball bearings to support the spindle. In fishing terms there is little to choose in casting distance between the two. However, plain bushes need re-oiling after every trip for a prolonged life. Bearings soak up enough oil to last for at least a months worth of trips. Also, the reel is smoother to cast and retrieve, and the bearings with care last three times as long as bushes.
Now that the basic principles have been explained, we'll look at combining the blocks and oil as a balanced casting control to suit all conditions and other relevant factors.
To begin it pays to standardize on a given grade of oil thickness. Small multipliers like those already listed are generally suited to 20/50 motor oil for general fishing and all but the most severe conditions. If you're new to multipliers, or not used to fishing at night with one, upgrade the oil to straight 30 grade and stick with it until your confidence improves.
Choose the largest pair of blocks supplied with your reel for maximum braking effect. These, combined with the thickness of oil will eliminate backlash caused by poor tuning of the reel. If you still have regular backlash then look to your casting style because that's where the problem is, not with the reel.
The reel will feel dead when cast set up as described, particularly with the 30 grade oil, but allows trouble free fishing.
In calmer weather with nothing to hold the lead back you should be able to replace the big blocks for the next size down, maybe even the smallest ones if you're casting with real power, but the oil stays the same. Never mess with the line capacity stored (more about this shortly) as some anglers and writers suggest, and never change the oil, just change the size of the brake blocks to suit the conditions.
When you get more proficient you can drop down to the smallest set of blocks and reduce the oil thickness. Bear in mind that in summer oil thins, and in winter thickens. You can get away with a thinner oil in winter than you can in summer.
Given average casting abilities the 6500 casts it's best with 20/50 oil and two small blocks. The 7HT works well with 3 in 1 oil and two small blocks, and not surprisingly so too does the original millionaires and the 6000ms, the predecesors to the 7HT. Only the very best casters can get away with only one block and thin oil in these models. If there's the slightest flaw in your casting style, these fast settings will seek it out sooner rather than later.
Some very experienced anglers suggest that you should reduce the amount of line on your reel, thus reducing overall spool weight, to make casting easier, especially during gales when lead speed reduces much quicker than in calm air conditions. This is bad practice.
Reducing line capacity means you can't line back if you're on a shallow beach that allows the tide in and out fast, you haven't the line to let a big fish run if need be, and if you snap out on a snag there is unlikely to be enough line for future casting. Casting distance is also drastically reduced because of the low loading. It takes much more effort to pull line from a low loaded spool than it does from a full one. Clutch release pressure is also increased accordingly as the line level falls.
Instead of half filling your reel in the first place, or more likely wasting good line already on the reel, it makes more sense to increase the braking on the spool. Increase the size of the blocks on the spool spindle, or if you're really worried put thicker grade oil into the bushes and bearings.
Bigger casting reels like the ABU 7000s and Penn 535's are more suited to fishing very rough weather, but suffer because of the larger spool and line capacity. Even then, with 30 grade oil in the bearings or bushes, and the largest blocks in place, these become docile enough for average casters.
It's rarely necessary, but if this heavy setting still causes you problems you can mix STP or 90 grade tractor oil in with the 30 to give a glue like thickness. If things are that bad though, you'd be better off with a fixed spool reel in the first place.
It's a fact that thicker reel line reduces the tendency for coils of line to spill from the reel into birdsnests, but at the expense of too much distance lost.
The other bad dodge is to tighten the pressure cap on the ends of the spindle that sit on the outside of the reels side plates. This tries to bend the spindle fractionally and also causes excessive wear on the spindle ends. Eventually things get so bad that the caps fully tightened cannot touch the spindle ends at all. Always make sure that the spool has slight movement from side to side when in place inside the assembled reel.
Line should be loaded to within an eighth of an inch of the spool lip. You can increase this a little when applied to bigger multipliers like the 7000. Braked with the correct blocks and required thickness of oil for the prevailing conditions there's no way a fully loaded spool will birdie.
Depending again on your casting ability, big reels like the ABU 7000 or Daiwa and Penn equivalent, because of their greater line capacity need heavier braking than their smaller cousins. On a 7000 expect to use a minimum of 20/50 oil and medium blocks in winter, and consider big blocks if there is a full gale blowing in your face.
The Shimano Speedmaster range run best for fishing on either 20/50 or straight 30 grade oils, as do the bigger Daiwa reels that are well run in.
Lubrication is simple with bushes, you just pour some oil in. Bearings need a different approach.
There is only one certain way to make sure that a clean bearing soaks up enough lubricant. Wash the bearing clean with petrol or lighter fuel and fully dry it. Put some of your chosen oil in to an old soup spoon and heat this over a candle or whatever until the oil has thinned. Now drop the bearings in to this and watch for bubbles coming to the surface as the oil penetrates the inner bearing. When these bubbles stop the bearing is fully lubricated. Cold oil does not fully enter a dry bearing.
The same grade of lubricant you use for the bearings should also be smeared sparingly along the length of the spindle at each side of the spool. Also remember to keep the brake blocks free from oil and grease for full braking efficiency.
These suggested settings are for fishing situations only. They should not be confused with what has been written regards setting reels up for tournament work on grass courts with the wind conveniently following from behind.
If you follow these settings and still suffer problems, then the greater chance is that it's you that is at fault, not your reel. Always look to your casting style as being the most likely source of the problem.