Outer ring - who uses and what are your findings

Systems that rely upon a center clamp or weight, such as the SME one, certainly are superior to doing nothing, but if the LP is truly warped in a nasty way, you cannot flatten the outer edge of the LP reliably just by clamping it at its center, no matter how artfully the platter is dished, etc.  And if that system works for one side of such a badly warped LP, then it is unlikely to work as well when you flip to the second side.  So, for really badly warped LPs, if you cannot bear to recycle them, I think you'd need a peripheral ring weight. In my experience, warping always affects the outermost grooves the most.

@lewm SME is not just a center clamp/weight. It shapes the record to the platter. You should know better.

@invictus005 wrote

@lewm SME is not just a center clamp/weight. It shapes the record to the platter. You should know better.

Reflex clamps are designed to couple a flat record to the platter.  In some instance, reflex clamps can tame slight warps but the results will be inconsistent due the fact that warps do not present the same on both sides.  IME, reflex clamps cannot solve larger warps, for those those you need a periphery ring weight.


  

@brf That’s not how SME works. SME system flattens a bolw shape warped record on either side. Surface of the platter and the bottom of the clamp are machined to a specific geometry. There’s a metal disc that is placed under the record. Once the clamp is threaded on, one can adjust the force to where the record is perfectly shaped to the platter. Insanely warped records become flat like glass on the SME. You guys really need to know what you’re talking about before posting. 

The ring system on the other hand is a cumbersome nonsense. It needs to be very heavy to work properly. You guys are not only wasting your money and time during every record change, but are also changing the properties of your platter and are possibly ruining your bearings. 

@invictus, if you are referring to the SME Type 20 collet clamp, it does not flatten poorly warped records as proven numerous times by my friend who owns a SME 20 with said clamp. BTW, bowed shaped records are merely a small sub set of warped records.