Does upsizing or downsizing split rings for lures such as crankbaits affect the lure in any way?

It will add or reduce weight depending on whether you downsize or upsize. That in turn can affect the baits action. I usually swap mine out with the owner hyper wire rings in the same size and see no difference in action.

I put together a split ring and treble hook kit back some years ago. Built up over a period of time. Still add to it as needed. I buy the VMC stuff from TW. Get a nice set of ring pliers and you are set for life. 

If I replace split rings, I replace them with ovals. Far less chance of breakoffs.

Sure it does.  Any tiny little thing you do to a crankbait changes it’s performance to some extent.  Different size split rings will change the bait’s buoyancy and can help or hurt the likelihood of the trebles tangling. 

On 9/28/2018 at 6:06 AM, NHBull said:

If I replace split rings, I replace them with ovals. Far less chance of breakoffs.

What is the reasoning behind this? Not calling you out or anything just genuinely curious. 

8 hours ago, ItsHardwick said:

What is the reasoning behind this? Not calling you out or anything just genuinely curious. 

With the oval, the over-rap of the ring is in the middle on the long side, farther away from where the line is going to rest.  With a circle, there is a better chance that the line is going to rest against the over-rap and cut itself

13 hours ago, NHBull said:

With the oval, the over-rap of the ring is in the middle on the long side, farther away from where the line is going to rest.  With a circle, there is a better chance that the line is going to rest against the over-rap and cut itself

That makes plenty of sense. Never occurred to me but that’s pretty smart.