piston rings??

Anyone That knows about this - explain to me - Low Tension piston rings & v/s standard piston rings ? Whats the real difference? My old napa guys have never heard of this ?? Educate me -Thanx

Older rings were cast iron. They were the standard for many years. They were low cost, required a rougher bore finish to seat properly, and still tended to use oil and wear out in 40-60K miles.
There was a time when chrome rings were used. Mainly for racing.
Newer rings usually have a coating on them, most use a moly coating. This requires a much smoother bore surface, little to no break-in time, uses less oil and lasts longer.
Due to these factors and better engineering of the ring groove that allows combustion pressure to help seal the ring, they don't require as much tension.

Thanx Rod - i do know about all the ring types and have used them all over the last 50 years . I was told by an enginebuilder tghere was some type difference in "Low tension " Rings - yet didnt get specific. I believe the roundy round racers use these yet not sure . These rings had 2 very thin rings below & above the oil ring & all 5 fit in the pistons oil ring area> ive never seen any like this before- and am curious as to why & what these are ??

Take a look at various ring manufacturer's sites for the info "straight from the horse's mouth".
Every oil ring I've seen have support rails top and bottom, but I haven't seen pairs above and below.
Low tension would mean less HP loss due to friction, but less oil control unless other changes are made. Tighter tolerances, different bore finish, etc.

Here's an article I just found. Circle Track mag is ususally written to a higher level than something like Car Craft, which is pretty much entry level.
http://www.stockcarracing.com/techarticles/scrp_0510_piston_rings_basics/index.html

More info
http://blog.raceology.com/2005/05/oil-ring-tension.html

Thanx ill look for some explanation on the mfgs sites have a good one