I see alot of production Shimano Spinning Rods with 18 mm dia reel seats. These seats are used on average size spinning rods up to 7.5' with under 1/2" in butt dia. I strive for lightness so I will use 16mm seats, also there is not as much side to side reel foot slop inside the reel seat hoods to contend with. Smaller spin reels in general go on these spin rods, So I'm wondering why use these larger dia. reel seats, it is strictly comfort? by the time you wrap your mit around a 16mm seat and attached reel foot, its plenty large enough for those who like oversize grips, OR is it a continuity thing where the seats dia is much closer to that of a standard finish dia. of pre-made cork grips both fore and aft? I never could quite figure out the rational behind using theses size seats?

I believe it is a comfort thing that is only noticable after a long days fishing. I have started making my cork grips a bit larger for this same reason.

rhr

I fdind that the 16mm seats are not comfortable when on the water for a day. I prefer the larger size seats. I save a little weight by cutting off some of the excess threaded part, so the difference in weight is negligible to me.

I tend to use whatever size seat fits the angler's hand. I often use size 20's on ultra light rods, if that's what the custom finds the most comfortable.

..............

You want to be sure the reel seat will accept the reel that will be used on the rod. Don't ask me how I know this but all Spinning reel feet aren't the same length.

S I N N I N G reels come in all sizes according to scripture. Dr. Bob