Yup it's a convert. The whippet has tons of rear mud clearance with 26" and popping in a 27.5" tire "looks" like it was made for it. Pretty sure a 2.2 or 2.3 would fit back there but I went with 2.1 Rocket Ron's front and rear setup tubeless. They were the closest match I could find to my...
My 650b...
On One whippet frame built up as a 1x10. 20.6lbs rolls nice and very flickable.
Would not change much at all from what I built, super fun bike that fits me perfectly.