Originally Posted by
arsprod
I'm on my 3rd set of tires trying to get something narrow enough to fit on the rear. The last set was Panaracer Gravelking 27.5 x 1.75 - too fat. I'm wondering at what point the tires are too narrow for the benefit of cushier 650's. I've got about 46mm space in the rear, currently have 700x40. Any advice?
What bike is this, by the way? One thing that helps when converting older frames to 650B is that the chainstay clearance usually opens up as you move backward. But the chainstays on some newer bikes are already manipulated to maximize tire clearance with the intended 700C wheels, so going to 650B wheels is just a lateral move. If I had such a frame, I'd probably just pick some supple 32-42mm 700C tires and call it a day.