I am sure the urethane formulas have changed somewhat.  However the oils and surfaces have changed dramatically too.  Haven't seen these international guys bowl, but anyone throwing a ball at 180 grit is either getting major rollout or is way up over 20 mph on a short pattern.  Maybe these short patterns are very high volume, and the guys are using the really dull stuff to blow a hole in the pattern without looping the ball too much.

I use urethane quite a bit myself, but I keep it buffed to 2000 or higher.  Key to urethane of any era is that it burns off too much energy turning a wide corner.  I use urethane to play more direct to the pocket than I can with resin.   

The old Hammers started turning as soon as they hit the lane. I got rid of all of mine in the mid 1990's when I accepted the fact that I couldn't hit the head pin with them. They hooked so early and so much that they hit really soft due to the expended energy. I have a hard time believing they would work on the standard house shot today. I know I couldn't throw one because I need my ball to skid.

I use the old Hammers on THS all the time.  I can rarely use reactive stuff, way too violent reactions.  Actually just picked up a couple Purple Hammers this week.  Can't wait to throw them.  My Burgundy is usually too strong so it's been the Red Hammer most.  Both of those hit great. 

I also have a Rotogrip Grenade, and the new Blue remake.  The Blue I've not had alot of use, it really creates alot of carry down, the others don't.  The Grenade is a pretty nice ball, it flares alot.  But it doesnt hit quite as hard as the Hammers. 

So, to summarize differences between modern and older urethane balls:

- Most modern urethane balls are manufactured with less or none of the materials that went into the urethane balls of the 1980s and early 1990s.

- Many older urethane balls have lower differential RG values than is common in most modern urethane balls.

- Older urethane balls are used mainly by bowlers who can play more of a direct hand-behind-the-ball line. Modern urethane balls are made to feel comfortable for bowlers who use more axis rotation.

- The lane oils and lane surfaces of today also have something to do with how modern urethane balls are made.

I have been a huge proponent of the older urethanes for quite some time. Why are they better? They are not necessarily better for EVERYONE but they do the same for a gicen class of bowler that the resin era did for a different class.

What reactive resin allowed was for the straighter players to  increase their entry angle so as to be able to increase their strike window to where the power players were.

The opposite is true for the use of urethanes in todays game. The power players are using urethanes to help control the wet/dry walled up lane conditions we see in leagues today. They also allow the power player to take advantage of the "track area" where the ham and eggers make their 200+ averages while stile gaining a margin of error they don't have with any of the newer resin balls.

Now, why are the older urethane balls better? Simple.....the cores and covers are not nearly as strong as today. The old Hammer core or the Turbo core are not weak but they are symmetrical, they lack flip blocks or multi-densities to help them flare and hook more. Many of the older urethane balls have the same hook potential as the current polyester balls. Control, predictaility and face it, they hit!....the cornerstones of the entire Faball line back in the late 80's....

Why do tournament bowlers like them? The same reason....control, predictability and carry....no fillers in the old balls make them transfer energy much more efficiently than some of the newer stuff. Newer higher flaring cores are heavier and require filler to get the ball to make weight. Filler is lower density and does not transfer energy as well. The older balls with the less complicated cores require little to no filler. Add these facts together and you get better carry from the older urethanes.

higher flaring cores burn energy faster and the filler does not transfer energy as efficiently so therefore you get less energy at the pins.

Again, advantage old school.....

So does the absence of light-weight filler material in older urethane balls make the Coefficient of Restitution (energy transfer) values in these balls fall outside the USBC ball approval requirements (minimum 0.739 and maximum 0.750)?

Thanks all you guys for sharing your knowledge and opinions!

 

I don't know what the ball appoval requirements were in the late 1980s and early 1990s. Perhaps there was no Coefficient of Restitution rules back then. Have the economics of present-day-ball-manufacturing (light-weight fillers) resulted in less effective urethane balls than back in the day?

The match between Barnes and Cho Yeung Sun is about 1h18min into this video:

http://www.ustream.tv/recorded/38008115

I don't know for sure that the grit on the Korean's urethane ball was 180. Could have been 360, I guess.

Doug explained it very accurately.  There is not even that much difference between the shells of todays urethanes and those from the 80's.  People forget that even us straighter guys could score big time with those urethane balls on short patterns when you could play way out.  Power players got the advantage in longer formats as the shot moved in, and they were able to create stronger recovery from inside with high rev rates.   As a low rev guy I can play straighter than a lot of the young guys can with urethane, giving me more places to use it.