I've seen a number of Norton racebikes with Commando disc brake in up to -72 classes. As the stanchions have the same taper on all Roadholder forks, it's a simple bolt on. A lot is written about improvement of the Commando brake. Parts for that readily available. Of course if making a new triple tree, you could put on a lot of different wheels and forks. My -72 Honda CB250 racer has got disc brake from another Honda model. With special triple tree. The Suzuki RG is changed to Yamaha forks, brakes and wheels. Because it had 18" wheel. No slicks available in that dimension.Only had to move rear disc in 5.5mm. I don't think the Roadholder is bad. I feel as confident as I do on the Ninja. A very fast racer tried my Manx, which has standard suspension and drum brakes last year. Comment: Handles well, horrendous brakes.