Thanks for the info. I am interested in the 14/18 combo. That size should also work well with the OS .18 motor even with maxx size tires if they are kept relatively small.
That .28 motor should be able to handle a 17 or 18 first gear. I have seen a Mammoth at the track with a 16 tooth first gear pinion and it had no problems. The gearing on the Mammoth is 13/47 in the diffs and 60/65 spurs and 11 plus pounds in weight so, with the 38/42's a larger first gear pinion could be used.



rolland