All of my reels are 7.1 g/r. I'm contemplating on getting a lower g/r for crankbait use, like a 6.5 or so. Will I notice a big difference between the two? 

For me, no. I use a 7.3:1 for cranks up to 12ft deep and im fine with it for hours of usage. As long as i turn the handle slower, i dont get tired

Deep cranking benefits from a 5:1 18" ipt give or take, up to that point it's all about preference. 

Grab a 15+ deep diver, tie it to your 500:1 gear ratio reel, fish it for an hour and then come back and tell me how did it go.

Yes

Some 6.xx reels have very similar "inches per turn" as some 7.xx reels.  Check the "ipt" to be sure. 

7 minutes ago, Yudo1 said:

Some 6.xx reels have very similar "inches per turn" as some 7.xx reels.  Check the "ipt" to be sure. 

I was looking at the Shimano  16 Met MGL 6.2 g/r. It has 24" ipt and the Shimano 16 Aldebaran 6.5 g/r has 25" ipt. 

For cranking and other reaction type baits, I'd definitely opt for the Met MGL. 

I like my Lew's BB1 5:1.1 reel. I like the slower ratio especially for deep crankbaits. It just feels better than trying to slow down with a faster ratio or maybe I am just old school.

For most cranking, use a 5:1 ratio. You can use a 6:1 for shallow cranks though.

1 hour ago, tander said:

I like my Lew's BB1 5:1.1 reel. I like the slower ratio especially for deep crankbaits. It just feels better than trying to slow down with a faster ratio or maybe I am just old school.

 

I'm like you in that regard, I'm not into this faster reel revolution. I wish they would still make some lower 5 ratio reels, though a 5.5:1 or 5.6:1 doesn't seem to be too fast.

Want really slow try a 3.8 i use this ratio for big wake baits

48 minutes ago, Maxximus Redneckus said:

Want really slow try a 3.8 i use this ratio for big wake baits

 

I'm in the slower reel preference myself.  5 Speed reels are the way for me when throwing most cranks & big bladed spinnerbaits.

I have a 3.8 reel (old Qunatum) and it's just TOO SLOW for anything I fish.   Works the baits OK I guess but once I hook-up it's next to impossible to catch up to a spirited bass coming at me.  Costs me fish so now it sits on the shelf as a nice "display"

A-Jay

Id buy 5.4:1 Abu Orra 2 Winch and save 320 bucks.

5 hours ago, Maxximus Redneckus said:

Want really slow try a 3.8 i use this ratio for big wake baits

 

I got a 3.8 Curado 200B, does just great with those deep divers and it's fantastic for slow rolling those double size double willow spinnerbaits.

I ended up getting a Lew's Tournament MB 5.6:1. Not too many people make a lower g/r in left handed...