Thought I'd post this as it might of interest to TXT-1 owners out there (and possibly TXT-02 and Jugg owners too). I recently bought an EzRun 4274 combo from Ebay, to fit either in my TXT-1 or the half track I'm building (In the big rigs forum). I did a trial fitment in the TXT-1 and with the aid of a home made spacer it fits quite well: Before and after, the 2 Trinity chameleon motors for size comparison against the 4274. The 4274 also has an extra 4mm on the diameter: