The Brazilian or spiral assembly is used on casting rods and consists in mounting the rings by turning them around the blank. The first ring is on the blank (reel side), then the next rings are on the side and finally the tunnel is under the blank curve, i.e. on the opposite side to the reel, inside the curve as on a spinning rod.
Rods on the market mounted in this way are exceedingly rare, as this particular type of mounting is not well established in anglers' habits and is therefore not widely marketed. The rodbuilding is therefore the solution to enjoy all the advantages of spiral mounting.
Stability
The first advantage of this set-up is that the blank is very stable when fighting a fish. Indeed, with the rings on the top of the curve, as is usually the case with casting rods, the rod tends to turn on itself during the fight. With the spiral mounting and its ring tunnel inside the curve, your rod gains in stability during fights.
The braid does not touch the blank
The second advantage of this set-up is that at high pressures, the braid is on the inside and not the outside of the curve, so it can't touch the blank, damaging it or itself. If you have a "traditional" casting rod at hand, I suggest you do the test and you'll see that your braid comes into contact with the blank, which is not good for either of you.
Less weight
In answer to the above problem, traditional casting rods require a large number of rings. With the Brazilian set-up, this problem disappears, allowing us to reduce the number of rings and consequently the weight. The mechanical properties of the blank are preserved and optimized.
Rotation angles
To place the rings on the blank, as a general rule, 3 rings are rotated. This means that the 4th ring (the first ring of the tunnel) is placed at 180°, i.e. opposite the reel.
On strong rods, you'll prefer a fast rotation (0°-45°-135°), while on lighter rods you'll opt for a gentler rotation such as 20°-70°-120° then 180°.
These are all approximate values, because even if you can use a protractor disc as shown in the photo, accuracy remains complicated and ultimately useless. The most important thing is, above all, to have an even distribution (which is easy to see with the eye) and to put the blank under pressure before varnishing to see if the braid doesn't touch the blank when rotating.
Right or left
The direction of rotation of the rings is irrelevant, but they naturally turn to the left when you're right-handed and vice versa, allowing you to rotate in line with your gaze. Indeed, for right-handers, the body, and therefore the gaze, is positioned to the left of the blank when the rod is held.
Throwing distance
It would be difficult to produce precise statistics, as this would require thousands of casts, but all those who use the spiral rig find no noticeable difference in casting distance compared with a traditional rig. For vertical anglers, the question doesn't even arise, and it would be a real shame not to take advantage of all the benefits offered by this ring arrangement.
About to install a casting rod? I can only recommend that you let yourself be tempted by the Brazilian attachment, for the mechanical efficiency it brings to your rod, but also for its inimitable look that will make your fishing friends jealous!
