My Vintage came with a 140/80/17. I've replaced it with a 140/70/17. I have a 150/70/ 17 on my EV and when I couldn't get that size, put a 160/70/17 on, which cupped and I took off. These bikes handle the best with a 140 rear tire. The 150 makes the bike just a bit harder to throw in and out of turns. I've even considered going down to a 140 on the EV. I don't know why people want to put fatter tires on their bikes.