ill have a go…
1.70a – harder wearing, faster rolling, less grip ,60 tpi threads per inch = durability… i think
2. 62a – softer compound = more grip but faster tread wear, exception = lighter but thinner sidewalls= easily damaged on sharp rocks
3.60a – even more grip but even faster tread wear
4. UST = tubeless for specific rims = no need for innertube
right thats my ten penneth….. how did i do?