I had a pair of Terrene Cake Eater tires installed on the bike a few weeks ago. On my commute to work this morning at 10F degrees I tried locking up the front wheel on a street covered by packed snow and ice. Instead of slipping on the ice the studded tires skidded without slipping out from under me. The tires were $340 installed by a LBS.   https://www.terrenetires.com/collections/cake-eater/products/cake-eater-26x40-light-folding-studs

There are mounting points on the seat stays that look like they are there for a frame lock but I have not been able to find one that would fit over the 4 inch tires and the fenders. I'm thinking the RR6+ frame was derived from another bike with narrower tires but I don't know if that is true or not.