That Huffy Pro Thunder Z2, 20 x 2.125 wheels, 32T/40T front with a 13T on the rear. GI is only 61.5 in the high gear, 42.9 for the low gear:

http://bmxmuseum.com/bikes/huffy/37409

The 44T/16T and 20" setup I have is 55 GI. Most new bmx are 25T/9T with 20" tires that's 55.6 GI. Special_k going 70 km round trip that's 43.5 miles, I'd like to know how long that took, because that kind of mileage on a 20" bike, I doubt I'd even try that if I were still a pre-teen or even teenager ? I'm impressed, must be an animal cranking that bike long distance like that. Heck of a commitment to go 20+ miles away from home in one direction. Because once you're there, it's 20+ miles back. But I guess if one could get the GI to approach 44/18 and 700C wheels (that's roughly 63-65 GI), maybe it's not as hard as I think it would be ? More like running an 26" atb at a lower gear setup for a couple of hours ? The 24" wheel bmx with 25T/9T is 66.7 GI. That's why I suggested that.