I have a 2001 Metro 36. I also have an older Bunton gear drive. I noticed that nowadays gear drive units all have smaller radius tires than my older Bunton which has the same size tires as my TTHP52. I spoke to a guy at the Textron booth at the Louisville EXPO and he said it was because of some ratio with the transmission. My Bunton has a different transmission than my Metro 36, this being the cause for different tires. I suppose the newer transmission is better, but I sure like the bigger tires my Bunton has over those of my Metro 36. Is this why the tires on gear drive units are so much smaller?