At the point where the projected spool axle line intersects with the “rear of reel” mark, use a square or 90˚ triangle to draw a line (A) perpendicular to the rod blank line. Do the same (B) for the spool tip mark.
Using calipers, measure the length of Lines A, B, & C. A & B are measured from the intersecting point on the spool axle line to the top edge of the rod blank line.
Note these numbers in millimeters and enter them in the boxes in the GPS interface. Label the measurements with the name of the reel and establish a reference file for the future. Choke point and reel upsweep are ALWAYS the same for a particular reel.
The information generated from this input will determine the upsweep of your reel. If you do not know what reel will be used, locate a similar reel series such as a 2500, 3000, 4000 and measure it. There may be some variation, but most reels in a given series will be within a degree or so of one another. One degree can sometimes move guides up to four inches so if you don’t have the reel to be used you need to be prepared to move guides a greater distance than if you were measuring the exact reel you plan to use.
Another method is to use the 27X formula created by Tom Kirkman. This method attempts to achieve the same height and angle information as an estimate based on a multiplier of the spool diameter. It is a good alternative, but not as accurate as actual measurements. Again, be prepared to move guides more than those positions generated by actual reel measurements.
NOTE: The majority of reels (not including the largest surf reels and some offshore reels) will have an upsweep that falls in a range of 2 to 4.5 degrees. This is represented by a variation of approximately 10 mm in the A & B lines. If your measurements show that “A” is 20 mm higher than “B”, you have most likely made an error in measurement. In most cases, A & B will be within 6 to 13 mm of one another with 10 mm being “average”.