Its funny how a subject like this gets covered a million times but on all the pulling sites on the net you can never start a good conversation between the real Pulling tires (Nichols, Pitbulls, Cepeks). Everything is top secret to the extreme!
FWIW Nichols seem to be the best pulling tire out there right now due to the huge weight loss you gain in the rotating mass. I was able to add nearly 100 pounds to the nose when swtiching. Also We needed to go down one point in the gearing. They BITE much harder then the Pitbulls. Also on a 20" rim they are an inch wider then the pitbulls.
Also if any of my diesel buddies know of some N/A trucks that take pulling seriously I am Selling my Hemi and upgrading.
http://www.racingjunk.com/Chassis/182119484/650ci-5-GOODWIN-HEMI.html