Ron's Tackle Tips — Reel speed vs. Reel ratio vs. Spool Diameter

Ken Jones

Staff member
Reel speed vs. Reel ratio vs. Spool Diameter

By Ron Crandall of Ron's Reel Repair (June 1999)

Did you know that a 5 to 1 ratio can be slower than a 2.5 to 1 ratio? A lot off people insist that they have a small reel with a 5 to 1 ratio, because they want to be able to bring in their fish as fast as possible. The part that they don't consider is the diameter of the spool .

An example would be the very popular Ambassadeur 5500 and 6500 series of reels. The maximum diameter of a spool of line is just short of 1-3/8 inches (1.38), and with a 5.3 ratio the retrieve distance is 23 inches per turn of the handle.

This is a great amount, but what happens when you have 75 yards of line out (very common for a lot of conditions). You now have a spool diameter of about 1-1/8 inches and that's a retrieve distance of 18-3/4 inches per turn of the handle .

Two other popular reels are the Penn 60 with a 2.5 ratio and the new Penn 185 with a 3.5 ratio. Both these reels use the same basic spool with a maximum diameter of 2-3/8 inches. Now this works out to be retrieve distances of 18-5/8 inches and 26-1/8 inches per turn of the handle. With 75 yards of line out the diameter is approximately 2-1/8 inches and that works out to a retrieve distance 16-5/8 and 23-3/8 inches .

As you can now see, if you have been following along, the Penn 60 with a 2.5 ratio has a retrieve distance within 2 inches of the Ambassadeur 5500 or 6500 with a ratio of 5 to 1, when used at a working length of line out of about 75 yards. But the Penn 185 with a 3.5 ratio is half again better with a retrieve distance of 23-3/8 inches per turn.

What's important here is that, when you are looking at reels for your particular uses, know all the variables: retrieve ratio, spool diameter and spool width, and calculate the retrieve distance at a working length of line, to make sure that you are really getting what you want.

To calculate this for each reel, use the following formula:

Diameter (of spool) X Pi X Ratio = Retrieve Distance (per revolution)

(Pi = 3.14 in case you don't remember your high school math)

Therefore, for the Penn 185 mentioned above the formula looks like this:

2-1/8 X 3.14 X 3.5 = 23-3/8, or converting to decimals which makes the calculations easier, 2.125 x 3.14 x 3.5 = 23.38

The last point to consider is the fullness of the spool. As the amount of line on the spool changes, the drag intensity changes. In a small reel the spool will empty faster than a large one. The drag on the small reel can more than double. This is one of the reasons for setting drags at 25% of the line strength. (See previous article on Setting the Drag) On the larger reel, the diameter doesn't change as much as the line is spooled off, and therefore the drag will not be changed as much.

Since some larger diameter reels can be had with higher ratios, and some smaller reels can be had with a lower ratio, it is important to do the math so you are getting exactly what you want.
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