9 out of 10 bracket racers wouldnt see the difference either way. Tubes can help stiffen the tire sidewall for pro tree racing....but not using tubes does save money and do lighten the wheel/tire package if absolute low ET and peak mph is that important to you ...but it would be very negligible.

MT slicks with tubes here too!

I am running Good Years without tubes. I put the Dawn dish washing liquid inside, but apparently not enough, as they do slowly loose air pressure in a few days.
We are foot braking only, if that matters?
The tires are not pinned, but they have not moved at all so far.
When I was buying the tires and wheels, the people I asked were not using tubes, so I went that way. In the past I always used tubes, but I had not raced in many years, and some things are done differently these days.


Mark

Hoosier, tubeless with screws...

For what it's worth I put 155 passes on my 10.5W x 31 M/T w/o tubes or screws. At the end the 60's fell off about from 1.32-1.33 to 1.35-1.36 on average, but were still consistent. I don't run screws. The tires turned 180 degrees during the first 30 passes, then settled down.
Doug

Something people never consider is that sometimes the air loss isn't porosity in the sidewalls - it's actually a bead leak from the low tire pressures not seating the beads.

Like i said I don't use tubes but I seal them twice with Dawn dish soap and water BUT I also don't use screws. I seal the tire to the rim with High Tack Gasket spray. Some guys that use screws forget about upping the tire pressure when they screw the slick to the rim and actually push the slick away from the rim creating an air-leak.

--------------- From the Mickey Thompson website tech--------------------



PROPER INSTALLATION OF RIM SCREWS WITH TUBE TYPE TIRES
1. Begin by drilling 12 equally spaced holes on both the inner and outer flange of the rim. See the diagram 4-A below.

Note: (Mickey Thompson strongly suggests that you use Drag slick mounting screws only, and that you follow the rim screw manufacturers suggested drill bit size.)

2. Trial run the screws through all 24 (32) holes. Running screws in the hole and back out again. A dab of grease on the screw will help.

3. Check for any sharp edges that the screw may have pushed out or caused during the trial run through. If any sharp edges are found de-bur and make sure the inner bead flange of the rim is smooth and clean.

4. Mount tire and tube. Have an experienced professional install the tire and tube on proper equipment. (Refer to Mickey Thompson Tech Bulletin #2 for tube mounting procedures and Mickey Thompson Tech Bulletin # 8 for proper procedures to check rollout (circumference).

5. Before installing the screws, inflate the wheel and tire assembly to 20 psi. Put a small amount of grease on each screw and install into wheel and tire assembly. Deflate assembly to operating pressure. Inspect rim flange and bead area for proper bead seating. If bead is not fully seated, re-inflate and reinstall screws.

6. For best results, static balance or "Bubble Balance" the assembly once screws are installed.

7. Periodically you should check the wheel for loose screws and inspect the rim bead area to be sure that there is no bead area separation.

Note: It would be good practice to inspect after each pass when you are checking your air pressure.

I ran Mickeys on the Duster tubeless and Goodyears with tubes. I run tubes in the Arrow in the Hoosiers for reaction time. I personally like a stiff sidewall and the tires seem to last quite a bit longer.

hoosier 10.5x30" no tube soap inside and they hold air like tubes are in. tires are screwed to the rim.