So what's the largest tires practical with a 30 Series comet and 6.5 Predator?

I'm in the beginning stages of planning my next project and I think I wnat to build something with high ground clearance, large tires from 22-25" in diameter, a 6.5 Predator and a Series 30 Comet torque converter. Looking at some of the gear ratio calculators out there I know 18" seems to be the largest you would want to go for dune buggys and go karts. But what about minibikes? Are tires in the 22" -25" too big regardless of what jackshaft and gearing you have? I don't want to be busting TC belts when out in the woods on the side of a steep hill in the middle of nowhere.

Some thoughts on gearing with the large tires and TC would be greatly appreciated. Thanks


Active Member
The super broncs as an example, with 8-10hp Tecumseh with the 30 series and 9 or 10 front sprocket to 60 rear works very well with 21/22x11 x8 tires.
The Coleman CT200U runs a 19 x 7 x 8, and I can tell you with a non hemi 212 and the 30 series with a stock sprocket, it has no problem at all, torque and speed. I would think it would handle an even bigger tire easily.