Okay, I'm really looking hard at some new flat side cranks (specifically either the 6th Sense Flat 75x or the Spro Little John) with these Labor Day sales going on but I'm hesitating because I'm not sure while pretty sweet lookin' if they're even necessary since I do have a few jerkbaits and several X-Rap XR10 slashbaits for cooler Fall weather. I know necessity is one of the most gray areas in fishing but if getting flat sides would be bordering on redundant with a decent supply of jerkbaits/slashbaits on hand already then i might switch gears a bit and look at something else. Thoughts anyone???

To me, jerkbaits and flat sided crankbaits have very different actions and are retrieved very differently, so I can’t agree with your equivalence.  Flat sides have a more rapid and more staccato wiggle on a straight retrieve and they also come through hard cover better, depending on the model.  Not saying jerkbaits aren’t a great bait for cool fall water but flat sides they are not.

BobP pretty much nailed it. You wouldn’t be feeding redundancy, you’d be expanding your arsenal by adding a new weapon. 

You need both. Flat sides for rip-rap and brush and jerk baits for points, channel swings, ledges and humps.

In the Fall, flatsides will usually out perform jerks, but can be thrown from the same setup if nessessary 

I don’t use jerkbaits in the fall but the 75x will out perform the little John in my own personal experience but I know there’s a lot of ppl who believe the opposite. I fish them till the middle of November but water doesn’t freeze over here in my neck of the woods once December comes I either throw a jerk bait or a jig or just fish for trout.

Until you find out if flat sided cranks work well for you, I would just buy a couple and try them. This "rule" of flat sided cranks working well in cold water or on lethargic fish I have seen regurgitated for years is bunk....so much of what works and what don't is body of water dependent.

 

On my home lakes flat sided lipped cranks haul water. They bite jerkbaits, lipless baits, and moderate to wide wobbling cranks year round here. I have given flat sided cranks a fair trial, and they are just not as effective, even in tough conditions...on the lakes I fish, which are mostly bluegill, perch, and craw forage base oriented. Very little shad, save for the alewives on Conesus, and yet still wider bodied, and wobbling cranks still work better there...for me.....Your results may be different, but you'll never know until you try a few.

I live south of ww2farmer and my experience is just the opposite regarding wide wobble round profile baits versus tight wobble flat sided cranks.  I choose flat sides year round and generally (not Always but more often than not) they outproduce wide wobble baits. I theorize that it has to do mainly with water clarity rather than time of year.  Southern lakes are usually more stained. Of course, anyone that says he knows exactly what bass will bite at any time, any place, in any water condition is usually talking through his hat.  Best to have a variety on hand and experiment.