[chrisguyw]

2)  chrisguyw:  Can you help me understand how an Air System wheel that has its gap filled with a foam insert is anything but marginally (infinitesimally?) superior to a non-AS wheel with no gap? 

• The filled gap would facilitate a flat tire circumference at rest, like the non-gap wheel. So both should feature equivalent corner grip.
  
• The foam insert would be somewhat lighter than the aluminum situated in the same region of the non-gap wheel. So for an AS wheel, it seems possible that centrifugal force acting on the foam and the unglued center section of the tire MIGHT contribute to tire growth and greater vMax - tire growth that would not occur to a tire glued to the rib of a non-gap wheel.
  
• Cost and time to mount & true tires on filled AS wheels would be greater than on non-gap wheels due to the materials and labor to put sponge in the gap of the AS wheel.
  

No doubt it works, or you wouldn't be going to the trouble.  I just wish to understand how far along the scale of Diminishing Returns we're talking about here.

Regards



Hello, Unlike the sponge tires that most of us grew up with, the tires used on current "plastic" 1/32 cars are made of Rubber/Silicone/Urethane, and are relatively "hard" by comparison......this coupled with the relatively light weight of these cars (Colin would approve), restricts the compression of the outside tire in a corner, and does not allow it to load significantly . 
The "rib" on most wheels results in a very thin amount of tire covering the rib, effectively "hardening" the tire even more, and further restricting its ability to compress/load.
Filling the "gap" on an AS wheel with foam, gives more depth to the tire, therefore increasing its ability to compress, and more progressively load the outside rear tire......this enhances grip. 
When AS wheels first hit the market, it was a fairly common practice to seal the wheel/tire on both beads, and inject a very small amount of air via a syringe,.....this did work well. allowing the tire to compress, but, it did not last long, with competitors routinely reaching for their syringes between heats. It did not take long for the clubs/commercial raceways to realize that this was far from optically correct (parents did not like their kids looking at syringes) and this practice was largely banned.

As far as the difference,...well,...it is not huge by any stretch, but, it does help, and, like lots of other things in slot car preparation, it is the sum total of the little things that separate the front running cars from the also rans......

Cheers
Chris Walker

The process,..should you think the work/expense is worth it  .

1/ Foam strips are cut from 1/32 1/24 sponge tire blanks
2/ Strips are glued to the wheel using flexible contact cement.....CA and other glue types will tend to "harden" to foam
3/ A tire truer is used to reduce the dia. of the foam, so it is just proud of the "ribs"........the ribs themselves can be taken down a few thou. as well, to effectively add to the tire depth, and, its compression.