NSR SIZED TIRE TRUERS

Russ - I have previously trued NSRs on my P&N (such as for the NSR rally series) and don't recall specific problems. But truing the NSRs on the P&N may have made your hubs microscopically oblong, or maybe the tires are just wonky (shifted during the truing process).

For this series - I trued my stock NSR Super-grips (brand new C7R Vette) on the HUDY.
I added Thunderslot 'foam donuts' to fill the gap and lightly ShoeGoo'ed the tires.
My Supergrips seem to be shedding/marbling and hence chatter a little in straight line. They also require a good rounding to prevent chatter in the corners.
The Moslers and 917s seemed easier to tune. Today - I can hit 4.1s immediately with my 917. When the tires and motor warm up (50 laps?) it runs consistently in the mid 3.9s without trying.
Both 917 and Mosler have a lower CG and dont have the big caboose as compared to the Vette.

I am not familiar with NSR cars.  I did not run the NSR Mosler or NSR Porsche 917 series and have no memory of the Modern GT series.  The Modern GT race reports said I ran three races in it but my car was not identified and I did not recognize any cars in the single race photo; maybe I ran a borrowed car.  The primary problem with my Corvette in this series seems to be trued tires.  The car chatters a lot with what appears to be out-of-round tires.  The NSR wheels seemed to be a snug fit on my P & N truer and I had trued them until they were butter-smooth, but on the track they bounce.  The initial problems seemed to be with gearing and weight placement.  After experimenting with weight placement and ordering and trying more NSR gears, I was able to get the car to handle much better, but the tires bounce.  I tried the wheels/tires on the Hudy truer at the track but the wheels are looser than they were with the P & N.  Very frustrating.  I am going to order another set of wheels and tires and give them another try.