Originally Posted by sosidge
Most carpet-specific tyres these days are 28mm. The 26 and 30 you have seen are probably outdoor "nitro" foams, which are do still work on carpet.
You would not want to run "nitro" fronts on carpet, only the rears. Nitro fronts are constructed diferently than normal foam tires used on carpet.
Parma, Jaco, TRC, and BSR are the tires most people use on carpet.