I have used the single, center strut to the brake bolt on all my bikes that have gotten rear racks save one for 50 years. Once I was past the flimsy Pletcher racks and onto the far stiffer Blackburn racks I thought I was golden. Now it appears I've been living in delusion for 40 years.

I have a bike that will continue that delusion 1 as soon as I can find a rack with a single strut or that can be adopted cleanly. To me, the single strut is a no-brainer for a cantilevered or disk braked bike.

DIsclaimer - I hate large loads in the backs of bikes. I would far rather carry heavy stuff in LowRiders up front. Weight aft is miserable if you love to climb hills out of the saddle and rock the bike.

Ben